Abstracts No.104 - 25th Victorian Universities Earth & Environmental Sciences Conference, 2012 by GSAustralia

Geological Society of Australia

ABSTRACTS Number 104

Victorian Universities Eartti and Environmental Sciences Conference

Monash University 25 October 2012

Geological Society of Australia Abstracts Number 104

25**^ Victorian Universities Eartti and Environmental Sciences Conference

' ^ \ ¥ U E E S € ^ 2012 Monash University School of Geosciences

PROGRAM & ABSTRACTS Edited and Compiled by: Ken McLean Melanie Finch Antoinette Stryk Steplnanie IVIills Hosted by: Sclnool of Geosciences IVlonasli University

25 October 2012 Monash University, Clayton, Victoria, Australia

Geological Society of Australia Abstracts Number 104 Proceedings of Victorian Universities Earth and Environmental Sciences Conference Monash University, Clayton, Victoria, Australia. 25 October 2012. Editors: Ken McLean, Melanie Finch, Antoinette Stryk, and Stephanie Mills ISSN 0729 Oil X © Geological Society of Australia Incorporated, 2012

Recommended citation: McLean, K. A., Finch, M. A., Stryk, A. and Mills, S. E. (eds), 2012, 25th Victorian Universities Earth and Environmental Sciences Conference. Geological Society ofAustralia Abstracts, 104, pp. 48. Example citation for papers in this volume: Finch, M. A., Fuentes, M. G., Hasalova, P., Becchio, R., Hunter, N., Weinberg, R. 2012. A previously unrecognised major orogenic front in Argentina. In: McLean, K. A., Finch, M. A., Stryk, A. and Mills, S. E. (eds), 2012,25th Victorian Universities Earth and Environmental Sciences Conference. Geological Society ofAustralia Abstracts, 104, p. 21. Copies of this publication may be obtained from: Geological Society of Australia Inc. Suite 61,104 Bathurst Street Sydney 2000 NSW, Australia or online at: www.shop.gsa.org.au

Geological Society of Australia Abstracts 104

25th Victorian Ur^iversities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Foreword The VUEESC is a v\/onderful opportunity for honours, nnosters, and PhD students to present their v\/ork to their peers and the local scientific connnnunity. This year v\/e had an unprecedented nunnber of subnnissions for presentations and have been able to offer tv\/o sessions for part of the day. This is a testannent to the strength of student research in Earth and Environnnental science in Victoria. The conference spans nnony areas of interest fronn research in meteorite fornnation and superflores, to structural nnodelling and nnetannorphic petrology. It is also a great networking opportunity with students attending fronn La Trobe University, RMIT University, UTAS, the University of Melbourne, and Monash University. All sessions for the VUEESC ore chaired by experts in the relevant field. We encourage speakers to take advantage of this opportunity and get feedback fronn the choir of their session during the breaks. The session chairs and judges are all staff nnennbers fronn the School of Geosciences at Monash University and we thank thenn for their generous support. We would also like to thank the postgraduate students of Monash University who hove donated considerable onnounts of tinne to assisting in the organisation of the conference. Finally, we would like to thank our generous sponsors, without whonn this conference could not occur. Melanie Finch and Antoinette Stryi<

VUEESC conference committee The 25th VUEESC is hosted by students of the Monash University School of Geosciences.

Convenors Antoinette Stryk Melanie Finch Ken IVIcLeon Annie Quinney

Program and abstract volume Ken IVIcLeon

Program and abstract editors Ken McLean Stephanie Mills Melanie Finch

Sponsorship and website Antoinette Stryk

l\/larl<eting and advertising Emily Finch Melanie Finch

Audiovisual technical support Thonnas Carnnichael Ken McLean

III

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference IVIonash University, 25 October 2012

Sponsors VUEESC 2012 proudly acknowledges the support of our sponsors.

GOLD SPONSORS

MONASH University

Monash University School of Geosciences

Science

nnpQ

Monash Postgraduate Association

monash I postgraduate association

Petroleum Exploration Society of Australia

Department of Primary Industries

State Government

Department of

Victoria Primary Industries

Geological Society of Australia Abstracts 104

26th Victorian Universities Earth and Environmental Sciences Conference Monosh University, 26 October 2012

SILVER SPONSORS

Amira International

INTERNATIONAL

3D Geo

Monash University Faculty of Science

MONASH University Science

Museum Victoria

MUSEUMVICTORIA Geological Society of Australia — Victoria Division

PGN Geosclence

PGM

BEnsciEncE

BRONZE SPONSORS

Royal Society of Victoria J R n g a l ^ n r t d g nf Founded 1854

Pictoria

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Program 08.00

Registration opens

09.00

Welcome and opening remarlcs: Prof. Sandy Cruden, Head of School of Geosciences, Monash University

09.05

Keynote address: Dr. Sastia Wilson

Session 1: Metamorphism, mineralogy, and geochemistry

09.25

Alastair Tait — Silicate partial nnelting in the early solar systenn: origins and nnechanisnns for crustal nnelt nnigration on the H-Chondrite parent body

09.40

Eleanor Mare — A connbination of radiogenic and innpact heating to fornn Type 7 ordinary chondrite nneteorites

Chair: Dr. Povlino Hasalova

09.55

Cattierine Wtieller — Phase equilibria In sapphirine-bearing granulites

10.10

Jessie Teske — Polycrystalline dionnonds and associated intergrov\/th nninerals fronn the Orapa kinnberlite, Botsv\/ana

10.25

Matttiew McGloin — How do v\/e explain a U-REE deposit like Valhalla? Unusual rare nnetal-enriched nnineralisation and its innplications for ore-forming fluids

10.40

Anne Whitwortti — Understanding the context of orogenic gold deposits in Archaean terranes: architecture 8c evolution of the stratigraphy north of the Woroongo Connplex, Agnev\/, Yilgarn Craton, Western Australia

10.55

Morning Tea

Session 2: Geoctironology, sedimentology, and palaeontology

20 mins

11.15

Kieran lies — The petrology, geochennistry and geochronology of the Middledole Gobbroic Diorite, Nevv^ South Wales

11.30

Matthew Felgate — A nev\/ and innproved geochronologicol investigation on the ultrapotossic rocks of the Alto Paronoiba Igneous Province, South East Brazil

11.45

Jim Driscoll — Clastic fades developnnent during Connbrian-Ordovician rift basin evolution in northern Tosnnania, Australia

Choir: Dr. Chris Mays

12.00

Matej Lipar — The fornnation of the pinnacles in Nonnbung National Park, Western Australia

12.15

Alana Stiarp — Cranial fornn and function in the largest ever nnorsupial, Diprotodon opfotum: a connporotive finite elennent analysis

12.30

Annie Quinney — The Late Cretaceous environnnent: unearthing evidence for changes in dinosaur diversity. Alberta, Canada

G60

Session 3: Atmosptiere and climatology

11.15

Ractiel Badlan — Multiscole analysis of convective monnentunn transport in convection-pernnitting nnodel sinnulotions

11.30

Yingjun Chen — Validation of TRMM doily precipitation estinnotes of tropical cyclone rainfall using PACRAIN data

Chair: Dr. Sosho Wilson

11.45

Sonya Fiddes — Extrenne snow foil and snow nnelt in alpine Australia

12.00

Tammas Lougtiran — Sinnulotion of the nneteorologicol effects of the S Fornocis superflore on Earth

12.15

Andrew McRobert — City and country scale CO2 fossil fuel trends fronn a very high resolution global dotoset

12.30

Helen Green — Exploring the potential of speleothenn poloeoclinnate records fronn S. E. Australia

12.45

Poster Session and Lunch

45 mins 1

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University. 25 October 2012

Session 4: Hydrogeology

13.30

Alex Atkinson — Using geochennical tracers to quantify groundwater-surface water interactions, and resolving the water sources and residence tinnes of water in upland catchnnents (Gellibrand River, Otway Ranges, Victoria)

Chair: Dr. Ben Gilfedder

13.45

Eamon Lai — IVlodelling surface- and groundwater nnixing of the bank storage and hyporheic zones

14.00

Tim Robson — The effect of lake loading on groundwater levels around Lake Tutchewop in the IVIurroyDorling Basin, southeastern Australia

14.15

Julia Noorda — Investigating innpocts of vegetation type on groundwater recharge in the Murray Darling Basin

14.30

Fahmida Perveen — Geology overshadows the effect of land use change: a paired catchnnent study in Southwestern Victoria, Australia

14.45

Joshua Dean — Plant uptake and aboriginal land nnanagennent controlling groundwater solute evolution on a southeast Australian granite

15.00

Audrey Delahunty — A laboratory study into the potential of alkalinity-producing covers to remediate acid nnine drainage

15.15

Afternoon Tea

Session 5: Stress and strain

15.35

Robin Armit — Evidence for Early Mesoproterozoic rapid tectonic switches in the northern Mount Painter Province, South Australia

15.50

Damiano DellTrtole — The generation of sheath folds in viscously stratified nnaterials: on analogue and nunnerical modelling approach

16.05

Sarati Goyen — Structural and sedimentologicol evolution of on incipient transform continental margin: an example from the Voile Colomojue, Gulf of California, Mexico

16.20

Nictiolas Hunter — Microstructurol evidence for the origin of thick ultromylonites: the El Pichoo shear zone, NW Argentina

16.35

Matttiew Edwards ~ A texturoi model of magma fragmentation due to strain localization: examples from the 2.56 Mo Cerro Golan Ignimbrite

16.50

Awards and closing remarks

17.00

Drinks and nibbles in the foyer

18.00

GSAV guest lecture: Adjunct Assoc. Prof. Rictiard Sctiodde

20 mins Choir: Dr. Laurent Ailleres

/ hour

Geological Society of Australia Abstracts 104

25th Victorian Uriiversities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Poster Program 12:45

Poster Session and Lunch

Zhitiao Ctien — Quantifying the energy dissipation of the overriding plate in three-dinnensional subduction nnodels

Adam Beall & Ben Mattier — Heterogeneous crustal heat-flow fronn 3D nunnerical modelling as applied to Victoria

Stefan Vollgger — Structural interpretation through innplicit 3D geological nnodelling

45 mins

Benoit Saumur — "UR DOWN ... MORE ENERGY!!!" — The dynannics of nnagnnatic sulfide liquids

Melanie Fincti — A previously unrecognised nnajor orogenic front in Argentina

Dan Uehara — Deposit characteristics of block and ash pyroclostic flows, and connparison with debris flow deposits: the 1990-1995 Mount Unzen Eruption (Heisei Shinzon), Kyushu, Japan

Jack Simmons — The eruption history of the Pre Lower Punnice 1, Lower Pumice 1 and Lower Punnice 2 eruption sequences, Sontorini, Greece

Julie Boyce — Triple magnna batches and a connplex eruption history of a monogenetic volcano: geochennical analysis of Mt. Rouse, Newer Volcanics Province, Australia

Julie Boyce — Victoria erupts! The Newer Volcanics Province of south-eastern Australia: a new database of eruption points and on updated nnap

#10

Daniele Redi — A contribution to the understanding of the eruptive behaviour of Sonnnna-Vesuvius; a nnineral chennistry perspective

#11

Sam Engwell — Ash dispersion to distal locations: inferences fronn tephro deposits in deep sea cores

#12

Wendy Stanford — Neutralisation of alunniniunn-rich acid nnine drainage to fornn a magnetic sludge

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference IVIonash University, 25 October 2012

Abstracts The following section contains the abstracts for both oral presentations and posters presented at the 25th Victorian Universities Earth and Environnnental Sciences Conference. The abstracts are alphabetised by primary author. An index of prinnary authors is available at the rear of the docunnent. A citation guide for citing abstracts In this publication is available on the innprint page on the inside cover of this volunne.

Awards A nunnber of prizes are to be avv^arded to the best oral presentation in each category, the best overall oral presentation, and the best poster presentation. The prizes are kindly provided by our sponsors.

Best Overall Oral Presentation (Best Student Paper Av\/ard)

Sponsored by PGN Geoscience

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Evidence for Early Mesoproterozoic rapid tectonic switches in the northern Mount Painter Province, South Australia R. J. ARMITI, R G. Bettsi, B. F. Schaefer^, L. Ailleresi 1 School of Geosclences, Monash University, Clayton, Victoria, Australia 2 GEMOC, Departnnent of Earth and Planetary Sciences, Macquarie University, Nev\/ South Wales, Australia

Structural mapping from the northern Mount Painter exhumed within 7Myr between 1592 Ma and 1585 Ma Province indicates that the metasediments of the Radium before switching once again during the onset of NW-SE Creek Group underwent both Mesoproterozoic and directed shortening during D3 (Armit et al, 2012). This Palaeozoic poly-deformation. Early north directed Di- time-frame is similar to that of modern orogens such as D2 deformation is accompanied by upper amphibolite the Late Miocene-Present Kaikoura Orogeny of southern fades metamorphism. This deformation is characterised New Zealand (Landis and Coombs, 1964; Kamp, 1984). by recumbent folds that are preserved in the hinges of An S3 fabric overprints the earlier S1-S2 fabrics in the NE-SW trending doubly-plunging upright F3 folds (Armit metasediments and extends into the Mount Neill Granite et aU 2012). U-Pb zircon dating identifies a consistent as a steeply dipping NE-SW trending gneissosity. The D3 maximum depositional age ca. 1596-1592 Ma for the event is constrained by the presence of this S3 foliation in Radium Creek Metamorphics across the Paralana Fault. the ca. 1585-1569 Ma Mount Neill Granite, the ca. 1552 Ma The timing of D1-D2 is constrained between this ca. emplacement age (Eraser and Neumann, 2010) of the 1592 Ma maximum depositional age and the minimum undeformed Hodgkinson Granodiorite and dating of ca. depositional age indicated by the truncation of the S1-S2 1555 Ma metamorphic overgrowths on zircons from the fabrics during the shallow-level emplacement of the ca. Radium Creek Group (Armit etal, 2012). By superimposing 1585-1569 Ma (Elburg et al, 2001; Eraser and Neumann, these events onto the regional Palaeo-Mesoproterozoic 2010; Neumann, 2001; Neumann et aU 2009) porphyritic evolution of the South Australian Craton, a series of rapid Mount Neill Granite. This indicates that the Radium Creek tectonic switches are evident and suggests the region Group was deposited, buried to mid-crustal levels and evolved in a back-arc tectonic setting during this period. References ARMIT, R. J., BETTS, R G., SCHAEFER, B. E, AILLERES, L. 2012.

KAMP, P. J. J. 1984. Neocene and Quaternary extent and geometry

207-226. DUTCH, R. A, HAND, M., CLARK, C. 2005.

LANDIS, C. A , COOMBS, D. S. 1967.

Constraints on long-lived Mesoproterozoic and Palaeozoic deformational events and crustal architecture in the northern Mount Painter Province, Australia. Gondwana Research 22,

of the subducted Pacific Plate beneath North Island, New Zealand: implications for Kaikoura tectonics. Tectonophysics 108,241-266.

Metamorphic belts and Cambrian reworking orogenesis in southern New Zealand. Tectonophysics 4, 501of the southern Australian Proterozoic Curnamona Province: 518. constraints from regional shear-zone systems. Journal of the MCLAREN, S., DUNLAP, W. J., SANDIFORD, M., MCDOUGALL, L 2002. Geological Society of London 162, 763-775. Thermochronology of high heat-producing crust at Mount ELBURG, M. A , BONS, P D., DOUGHERTY-PAGE, J., JANKA, C. E., Painter, South Australia: Implications for tectonic reactivation NEUMANN, N., SCHAEFER, B. 2001. Age and metasomatic of continental interiors. Tectonics 21. alteration of the Mt Neil Granite at Nooldoonooldoona Waterhole, Mt Painter Inlier, South Australia. Australian NEUMANN, N. 2001. Geochemical and isotopic characteristics of South Australian Proterozoic granites: implications for Journal ofEarth Sciences 48, 721-730. the origin and evolution of high heat-producing terrains. FODEN, J., ELBURG, M. A , DOUGHERTY-PAGE, J., BURTT, A 2006. The Department of Geology and Geophysics, University of timing and duration of the Delamerian Orogeny: correlation Adelaide, Adelaide. with the Ross Orogen and implications for Gondwana NEUMANN, N., HORE, S., ERASER, G. 2009. New SHRIMP assembly Journal of Geology 114,189-210. geochronology from the Mount Painter Province, South ERASER, G. L., NEUMANN, N. L. 2010. New SHRIMP U-Pb zircon Australia. In: Korsch, R. J. (Ed.), Broken Hill Exploration ages from the Gawler Craton and Curnamona Province, South Initiative: Abstracts for the 2009 Conference. Geoscience Australia, 2008-2010. Geo science Australia. Australia. HARRISON, T. M., MCDOUGALL, 1.1981. Excess in metamorphic rocks from Broken Hill, New South Wales: implications for SANDIFORD, M., HAND, M., MCLAREN, S. 1998. High geothermal gradient metamorphism during thermal subsidence. Earth '^^Ar/^^Ar age spectra and the thermal history of the region. and Planetary Science Letters 163,149-165. Earth and Planetary Science Letters 5 5 , 1 2 3 - 1 4 9 . Keywords: poly-deformation, tectonic switches, ductile structures Email:

robin.arnnit@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Using geochemical tracers to quantify groundwater-surface water interactions, and resolving the water sources and residence times of water in upland catchments (Gellibrand River, Otway Ranges, Victoria) A. ATKINSON! 2,

Cartwrighti 2, B. Gilfedderi 2

1 School of Geosciences, Monash University, Clayton, Victoria, Australia 2 National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia

Geochemical tracers such as ^^^Rn, Chloride, ^H and i^c catchment represents a large relative area and a source are used to assess how groundwater fluxes vary spatially of significant volumes of surface water for many rivers. and temporally in the Gellibrand River of SW-Victoria. In the high-rainfall areas of Victoria, upper catchment Results show the river is largely groundwater fed, with a tributaries are also perennial indicating the presence of dominant groundwater contribution to the river occurring long term water storages which provide water to the river through a hot-spot discharge area. This pattern is seen between periods of rainfall. Current ^H data shows that all year round at different river stages, and is clearly the age of water flowing out of the upper catchment of the evident in all tracers. Further to this, measured ^^^Rn Gellibrand has a mean residence time in the decadal range. concentrations from groundwater bores over a period of Groundwater is unlikely to be the major long term store, as over one year are shown to vary through time, with the tributaries here flow over relatively impermeable basement largest variation in groundwater ^^^Rn values occurring rock without significant near-stream alluvial deposits. This across the catchment (i.e. between bores). Taking this study therefore attempts to geochemically detangle what into account is shown to be extremely important when the main sources of water in the upper catchment of the determining the groundwater end member in ^^^Rn mass Gellibrand River are, by focusing on a number of possible balances, as failure to do so can lead to large discrepancies water flow-paths through the soil zone. (> 50%) in calculated groundwater discharges. The upper Keywords: Email:

groundwater, surface-water, radon, upper catchment

alexander.atkinson@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Multiscale analysis of convective momentum transport in convection-permitting model simulations R. BADLAN School of Earth Sciences. University of Melbourne, Porkville, Victoria, Australia

Tropical convective clouds are crucial for the redistribution of heat, moisture and momentum in the atmosphere. They can form various regimes, from disorganised cumuli to mesoscale convective systems which are regions of organised convection and are the largest of the convective storms. The forecasting and numerical weather prediction of these systems has proven to be difficult. Vertical fluxes of horizontal momentum induced by organised convection are affected by factors such as the environmental wind shear, pressure gradients, and the strength of the density current — in turn they influence the development and regime of the clouds, as well as the larger-scale flow due to the countergradient or downgradient transport they induce. The multiscalar nature of organised convection complicates the analysis and presents a challenge in understanding the nature of the momentum transports.

Keywords: Email:

This research investigates momentum transport by separating the convective and mesoscale transports via statistical analyses to determine the characteristics of various regimes using idealised and real simulations from the WRF model. Initial analysis shows the mesoscale and convective transports change throughout a convective system's evolution and a noticeable effect of the mesoscale momentum transport on the large-scale flow. The momentum transports from convective and stratiform regions are also being identified. This work will result in a better understanding of how both the mesoscale and convective scale momentum transports are represented by parameterisation schemes in current models, as these will be required for the foreseeable future in global and climate simulations.

tropical convection, momentum transport, mesoscale convective systems

rbadlan@student.unimelb.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference IVIonash University, 25 October 2012

Heterogeneous crustal heat-flow from 3D numerical modelling as applied to Victoria A. R BEALL, B. R, MATHER School of Geosciences, Monosh University, Clayton, Victoria, Australia

Victorian heat-flow is extremely heterogeneous near the surface, as demonstrated by heat-flow measurements. This is related to complex geology and has implications for estimating temperature in the upper crust. The 3D distribution of re-parameterised thermal conductivity and heat-producing-elements (HPE) must be approximated in order to infer upper crustal heat-flow. Heat-flow at depth is forward modelled, as accurate knowledge of thermal parameters rapidly diminishes with depth. This uncertainty is assessed using parameter sensitivity analysis and validation using near-surface data, with their own inherited probability distributions. The Murray Basin, Otway Basin and Stawell Zone cannot be assimilated into one thermal approach. We differentiate upper and full crustal thermal models, the former of which is well constrained and facilitates the exploration of basin-scale structures, the latter resolving regional heat-flow trends. An impressive dataset relevant to thermal modelling of the Keywords: Email:

crust beneath Victoria is available including seismic, heatflow, and experimental data related to thermal parameters. These datasets however have not yet been utilised in any published thermal models of Victoria. CAD models are used to assign 3D temperature and pressure-dependent thermal conductivity functions and HPE distribution. We calculate conductive heat transport using Underworld, a finite element, particle-in-cell software, and its geothermal plugin. Flexible boundary conditions allow the integration of variable heat-flow from beneath the model domain. Preliminary results indicate that the distribution of crustal HPEs related to buried Proterozoic crust is an important influence on surface heat-flow variation and is complicated by lateral heat-flow effects. These preliminary models infer an anomalously high transient mantle heat-flow contribution. The Otway Basin's structure and lithological variation is also shown to overprint basement heat-flow variation.

heat flow, 3D numerical modelling, uncertainty analysis. Underworld

ben.mather@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Triple magma batches and a complex eruption tiistory of a monogenetic volcano: geoctiemical analysis of IVIt. Rouse, Newer Volcanics Province, Australia J. BOYCE, I. Nicholls, R. Keays, P. Hayman School of Geosciences, Monash University, Clayton, Victoria, Australia

Mt. Rouse is the largest eruption centre in the Newer Volcanics Province (NVP), featuring triple the magma volume of that erupted from other volcanic centres. Situated at Penshurst, Victoria, in the Western Plains subprovince of the NVP, Mt. Rouse is a complex volcano with at least eight eruption points. The eruption centre is 120 m higher than the surrounding plains, composed of lava and pyroclastic deposits, v^th a lava field extending 60 km to the coast at Port Fairy. A detailed stratigraphic and geochemical analysis of Mt. Rouse reveals three distinct magma batches were involved in the complex eruption history of the volcano. These batches differ in chemical composition, ranging from basanites to trachybasalts through to alkali basalts. There is evidence of both sequential and simultaneous eruption of these magma batches. The southern cone features a basal sequence of batch C then B scoriae and batch A lava before becoming more complex. An unusual proximal surge deposit containing distinct products of two magma Keywords: Email:

batches in the form of Pele's tears and hairs from batch A and scoria from batch B is found between the basal lava and overlying scoriae of batch B. In addition, there is much evidence to suggest that, unusually, three magma batches were erupted from either the same vent, or in close proximity to one another, with no evidence of mixing. Preliminary petrogenetic modelling of primitive samples suggests differing depths of formation of these magma batches, from an enriched mantle source. Monogenetic volcanoes are the most abundant volcano type on Earth. The NVP, a continental intraplate basaltic volcanic field, was thought to contain monogenetic eruption centres vdth single magma batches and simple evolutions. This study, along with recent research into other volcanic centres in the province, reveals that some have undergone more complex evolutions. This may have implications for petrogenetic modelling in the NVP and the study of other monogenetic fields.

Newer Volcanics Province, intraplate volcanism, magma batches, monogenetic

julie.boyce@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Victoria erupts! Ttie Newer Volcanics Province of soutti-eastern Australia: a new database of eruption points and an updated map J. BOYCE School of Geosciences, Monash University, Clayton, Victoria, Australia

The continental intraplate Newer Volcanics Province (NVP) constitutes the most recent phase of volcanic activity in Australia, and with eruptions spanning from 4.6-0 Ma, is still considered active. The NVP is a supposedly monogenetic volcanic field forming part of the Kanawinka Global Geopark, and is composed of the products of shortlived basaltic volcanoes in the form of scoria cones, lava shields and maars. This study introduces an updated map of the NVP, showing the distribution of the types of volcanoes, focusing on eruption style. A spreadsheet was produced, recording names and coordinates of volcanic centres and their associated eruption points from various sources, and was used to document deposit type (e.g. lava, scoria, spatter, composite, unknown). This formed the basis for the new map. Volcanic centres in the NVP are described as either simple or complex. Simple volcanoes are dominantly of one form with simple morphologies and few eruption points, described as Keywords: Email:

scoria cones, lava shields, maars or unknown. Complex volcanoes feature multiple eruption points with complex morphologies. Magmatic volcanic complexes feature a combination of lava shields, scoria cones and spatter cones (e.g. Mt. Rouse). Maar volcanic complexes feature exclusively phreatomagmatic eruption products (e.g. Lake Purrumbete), and Maar-cone volcanic complexes feature a combination of magmatic and phreatomagmatic eruption products (e.g. Mt. Gambier). Some 704 eruption points have been documented from > 4 1 5 volcanic centres across the province. This research has highlighted the need for further research into the Newer Volcanics Province, as many of the apparently "simple" volcanic centres are likely to be more complex in nature. A spreadsheet database will be made freely available to download for research purposes, along with shapefiles for ArcGIS and kml files for Google Earth.

Newer Volcanics Province, Australia, intraplate volcanism

julie.boyce@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Validation of TRIVIIVI daily precipitation estinnates of tropical cyclone rainfall using PACRAIN data Y CHENi, E. E. Ebert2, K. Walshi, N. Davidson^ 1 University of Melbourne, Porkville, Victoria, Australia 2 Centre for Australian Weather and Clinnate Research (CAWCR), Bureau of Meteorology, Melbourne, Australia

Since its launch in 1997, Tropical Rainfall Measuring Mission (TRMM) precipitation products have been widely used in tropical cyclone (TC) rainfall studies. As satellite data are indirect estimates of rainfall, it is important to evaluate their accuracy and expected error characteristics. Previous validation studies were mainly made over land, with no TRMM validation studies of TC rainfall having been done over the ocean before. This study evaluates the latest release TRMM 3B42 version 7 (V7) estimates of daily rainfall in TCs using the Comprehensive Pacific Rainfall Database (PACRAIN) of 24 h rain gauge observations. The evaluation is performed on two different terrain types: low-lying atoll sites (assumed to represent open-ocean conditions) and coastal and island sites (over land). The results show that Keywords: Email:

TRMM 3B42 has good skill at detecting intense TC rainfall, with good correlation and pattern matching with PACRAIN observations. However, it tends to overestimate heavy rain frequency on atoll sites, but tends to underestimate heavy rain frequency on coastal and island sites. Overall, TRMM is better able to estimate the intensity of TC heavy rain over ocean than over land. It is least skillful at coastal and island sites with high elevation, where it significantly underestimates TC heavy rainfall, suggesting that TRMM 3B42 is unable to capture orographic enhancement during TC landfall. Finally, results from V7 were compared with results from its predecessor. Version 6, showing that Version 7 of TRMM 3B42 has higher value on average for TC rain. The reason for this bias discrepancy requires further study.

TRMM, verification, tropical cyclone precipitation

y.chen@bonn.gov.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Quantifying the energy dissipation of the overriding plate in three-dinnensional subduction models Z. CHEN, W. R Schellart, J. C. Duarte School of Geoscier^ces, Monash Ur^iversity. Clayton, Victoria, Australia

It is generally accepted that subducted slabs provide the main driving force for plate motion. This force directly pulls the trailing plate coupled to slabs. Meanwhile, sinking slabs drive flow (poloidal and toroidal) in the ambient mantle, and this excited mantle flow generates viscous traction at the base of the plates, which lead to deformation of those plates. In this whole process, the potential energy of the sinking slab is the only energy source to maintain the slab bending dissipation and mantle circulation dissipation. In most previous analogue and numerical models, it is proposed that most of the slab's total potential energy is used to drive mantle flow around and beneath the plates, whilst only small portion is used to drive the bending of the subducting plate. Furthermore, it is clear that the force and energy to induce deformation of the overriding plate also originally comes from the subducted slabs. Such deformation involves extension, leading to the formation of backarc basins, or shortening, resulting in the formation of cordilleran mountains. However, until now there has been no idea how much of the energy is consumed in Keywords: Email:

this deformation process. Here we present fully dynamic laboratory experiments to investigate the force and energy dissipation of the overriding plate deformation (extension or shortening), and compare them with the negative buoyance and total potential energy of the subducted slab, respectively. The 3D models that do include an overriding plate are free at the trailing edge and boundary. These models show that during trench retreat the overriding plate extends the whole time. Velocities of plates and trenches are at their maximum before the tip of subducting plate hits the bottom of the box (representing the upper-lower mantle transition zone). The extensional force within the overriding plate also reaches maximum before the slab tip hits the bottom, and is only a small portion compared with the negative buoyance of the subducted slab (on average 1-4% and maximally 5%). The trend of the extensional energy dissipation rate within the overriding plate is almost the same as the extensional force, but its percentage of the slab's potential energy release rate is even less.

Subduction, extensional force, negative buoyance, energy dissipation, analogue modelling

zhihao.chen@sci.monash.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Plant uptake and aboriginal land management controlling groundwater solute evolution on a southeast Australian granite J. DEANi 2, J. Webbi 2, G. Jacobsen^ R. ChisarP, E. DreseH 1 Environnnental Geoscience, Departnnent of Agricultural Sciences, La Trobe University, Bundoora, Victoria, Australia 2 National Centre for Groundwater Research and Training, La Trobe University, Bundoora, Victoria, Australia 3 Institute for Environnnental Research, Australian Nuclear Science and Technology Organisation (ANSTO), Menai, New South Wales, Australia 4 Departnnent of Primary Industries Victoria, Bendigo, Victoria, Australia

Groundwater geochemical signatures are typically rainfall of and H^SiO^ is ascribed to plagioclase considered to be derived from rock-water dissolution and weathering, while SO^" enrichment is ascribed to pyrite weathering interactions. However, many major elements oxidation, indicating that rock weathering reactions play (Ca^"^, K+, HCO;, Mg2+, S, and Si) are essential plant a role in this setting. However, in most samples, after nutrients, and are removed from rainfall, soil-water and subtracting rainfall input, there is wholesale depletion of groundwater, where soils are depleted in these species. all measured ions. This prevents the use of the plagioclase, This in turn affects the solute composition of infiltrating biotite and K-feldspar chemical weathering reactions in water. Conventional methods of determining relative the mass-balance, as these release cations (Na^"^, K"^, Mg^"^ groundwater solute contributions from specific rock and Ca^^), all of which are depleted in the groundwater weathering reactions were carried out for a pair of sub- with respect to rainfall. Depletion is not due to mineral catchments in the Dwyer Granite, southwest Victoria, precipitation, as X-ray diffraction indicates this is not Australia. This method was adapted for southwest Victoria occurring. Nor is it due to cation exchange, as there is by standardising all species to rainfall CI" to remove the no balancing import of cations or significant acidification effects of evapotranspiration. While this step is commonly of the ground water. The depletion is instead attributed to omitted in high rainfall, northern hemisphere studies, it is plant uptake. The elements taken up by the vegetation have important for the Australian setting, where groundwater not built up in the system either, rather they were instead solutes are primarily derived from the concentration of exported as a result of past land management systems, rainfall by evapotranspiration. In a few groundwater specifically Aboriginal fire regimes where the land was samples in the study area, enrichment with respect to burnt repeatedly, exporting nutrients from the system. Keywords: Email:

rock weathering, ground water chemistry. Aboriginal burning, plant uptake

jf3dean@students.latrobe.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference IVIonash University, 25 October 2012

A laboratory study into the potential of alkalinity-producing covers to remediate acid mine drainage A. J. DELAHUNTY, J. Webb Environmental Geoscience, Departnnent of Agricultural Sciences, La Trobe University, Bundoora, Victoria, Australia

Acid Mine Drainage (AMD) is an ongoing environmental consequence of the mining industry throughout the world. It forms through the oxidation of sulfide-bearing rocks and produces low pH water with high concentrations of heavy metals. AMD is frequently generated within waste rock piles at mine sites. To stop AMD production, alkalinityproducing covers composed of carbonate material are sometimes used to cap the rock waste. This technique has shown some success, but seems dependent on external factors such as rainfall. To further investigate the potential of alkalinity covers as a remediation method, 14 leachate columns were constructed and designed to mimic the behaviour of waste rock piles. The leachate columns contain (from top to bottom) fine sand, quartz pebbles, sulphide-containing rock material (with variable acid generating potential) and quartz pebbles. The mineralogy Keywords: Email:

of the acid-generating material, identified using X-ray diffraction, was highly variable. Three different alkalinity covers were used: limestone, lime (calcium hydroxide) and magnesium oxide. Geochemical analysis of the leachate from the columns suggests that the weathering of minerals within the waste rock plays a significant part in buffering the water. Columns with carbonate minerals did not generate AMD, whereas the leachate from the other columns fell to a pH < 2.5. The immediate effect of the alkalinity covers varied depending on the material. The application of calcium hydroxide and magnesium oxide resulted in an immediate increase in the pH of the leachate. The limestone had only a small immediate effect, but ongoing analysis will determine its effectiveness as an alkalinity cover, and the suitability of the other covers as a long-term treatment options.

remediation, alkalinity-producing covers, acid mine drainage

ajdelalnunty@students.latrobe.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

The generation of sheath folds in viscously stratified materials: an analogue and numerical modelling approach D. DELL'ERTOLE, W. R Schellart School of Geosciences. Monash University, Clayton, Victoria, Australia

Sheath folds have been identified in different kinds of rocks silicone. The model is deformed using a specifically and tectonic settings around the globe. The formation designed machine that imposes a simple shear. A nonprocesses of sheath folds in rocks with high viscosity cylindrical deflection is mechanically induced on the pink contrasts, in simple shear conditions, is still an open layer before the beginning of the experiment, and it debate. This work shows a combined approach to the represents a natural anisotropy, which will later evolve into problem, using both analogue and numerical modelling a sheath fold. At the end of the deformation, the model to investigate the importance of some of the influencing is cut and the sections of the fold are analyzed. The parameters involved in sheath fold generation. The numerical models are run using the Underworld modelling investigated parameters are the relative viscosity of the framework, and they are benchmarked with the results layers and the thickness of the high viscosity layer. The of the analogue models. Both the approaches show the analogue model includes one planar thin layer of higher progressive development of the fold, evolving from sheath viscosity silicone in between two layers of low viscosity to tubular geometries. Keywords: Email:

sheath folds, analogue modelling, numerical modelling, structural geology

damiano.dellertole@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference IVIonash University, 25 October 2012

Clastic facies development during Cambrlan-Ordovlclan rift basin evolution In northern Tasmania, Australia J. R DRISCOLLi 2, M. Hal|i 1 School of Geosciences, Monosh University, Clayton, Victoria, Australia 2 Hot Dry Rocks Pty. Ltd., 36 Garden Street, South Yarra, Victoria, Australia

Initial rifting as a result of extensional collapse of the energy levels and run-off rates would have been an order Tyennan orogeny in the Late Cambrian-Early Ordovician of magnitude greater, fluctuations in energy levels more of northern Tasmania created a complex system of extreme and high energy events more frequent. Likewise, grabens and half-grabens, providing accommodation wind processes would have played a far greater role than space for large volumes of basement-derived sediments, at present with regards to the removal of clay- and siltdominated by extensive alluvial fans and braided river sized particles from the depositional setting, and this may facies. Depocentres migrated both spatially and temporally explain the paucity of claystone and siltstone in these as rifting continued and thickness variations and dramatic terrestrial environments. Fundamental differences in the differences in the coarseness of the conglomerates provenance of the clasts within the conglomerates and have been used to identify the active basin margin sandstones is evident at various localities in northern faults of tectonically active troughs. Palaeogeographic Tasmania; major clast-types include Proterozoic quartzite, reconstructions of the Arenig demonstrate that Tasmania Cambrian chert, volcaniclastics and ultramafics. It is was located on the eastern margin of the Gondwana apparent that the various depocentres were separated landmass, sited north of the palaeoequator between by topographic highs, and the sedimentary fill of these latitudes 10° and 20°. The lack of sediment stabilisation depocentres reflects the lithological composition of the by plants and rootlets in this Early Palaeozoic vegetation- highs. Rifting was followed by an Ordovician-Early free terrestrial landscape resulted in alluvial and fluvial Devonian sag phase, which resulted in the terrestrial depositional processes being markedly different than their conglomerate facies being overlain by sediments with an present day counterparts since vegetation typically exerts increasingly marine character. significant influence on hydraulic processes. In particular, Keywords: Email:

alluvial fan, braided fluvial, Tasmania, Combrian-Ordovician, vegetation

james.driscoll@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference IVIonosh University, 25 October 2012

A textural model of magma fragmentation due to strain localization: examples from the 2.56 Ma Cerro Galan Ignimbrite M. J. EDWARDS, R. A. F. Cas, R. R Weinberg School of Geosciences. Mor^ash Ur^iversity, Clayton, Victoria, Australia

Magma fragmentation during volcanic eruptions has traditionally been viewed as a homogeneous steadystate process, resulting from the explosive expansion of vesicles at a critical confining pressure within the volcanic conduit. Interestingly while the products of these eruptions have been extensively studied, there has been little effort to constrain the variety of pyroclast types and morphologies with the assumption of steady-state magma fragmentation. We conducted textural analyses of backscattered electron images of coeval cognate pumice and ash deposits taken from the 2.56 Ma Cerro Galan Ignimbrite Keywords: Email:

(CGI), Argentina. Four major clast types are recognized within the ash deposits of the CGI; free crystals/crystal fragments, cognate pumice, cuspate glass shards and framework clasts. Using a morphological comparison of these clast types, a new textual model of magma fragmentation has been developed. This model indicates that magma fragmentation is a heterogeneous process occurring along a fragmentation zone within the volcanic conduit and is primarily controlled by strain localization within the silicate melt during ascent.

pyroclast, magma fragmentation, Cerro Galan Ignimbrite

matthew.edwards@monash.edu

Geological Society of Australia Abstracts 104

25tln Victorian Universities Eartin and Environmental Sciences Conference IVIonash University, 25 October 2012

Ash dispersion to distal locations: inferences from tephra deposits in deep sea cores S. L ENGWELLi, R. S. J. Sparks^, R Baines^ 1 School of Earth Sciences, University of Bristol, Bristol, United Kingdonn 2 Deportnnent of Infrastructure Engineering, University of Melbourne, Parkville, Victoria, Australia

Large explosive eruptions have the power to emit hundreds are deposit thicknesses, with trends that are consistent of cubic kilometres of material into the atmosphere. across distal sub-aerial, lacustrine or deep-sea sites. Such eruptions could have catastrophic implications The Campanian Ignimbrite is bimodal to distances of for continental sized areas, especially with regards ~ 1000 km after which it becomes unimodal. Between to agriculture and aviation. To understand dispersal 1000 km and 2300 km from source there is little variance processes, we rely on theoretical modeling and analysis in the grain size trend or median grain size, which resides of deposits from past explosive eruptions, combined with between 40-60 (jLm. The presence of pure ash layers at observations of smaller historical eruptions. This study great distances from the volcano show that an efficient uses grain-size distributions and thicknesses of ash layers mechanism is required for deposition over geologically in deep-sea cores to determine key characteristics of the instantaneous time-scales. We conclude that submarine Campanian Ignimbrite eruption (39,000yrBP; VEI 7). tephra deposit parameters provide good information for Deposits from across the dispersal axis to distances of robust estimation of eruption characteristics. We aim to 2300 km were analysed. At any given distance from the use this information to model the eruption using a gravity source, tephra thicknesses can differ greatly depending on current model. The intrusive power of proximal plumes depositional environment: on land, fine ash in particular from very large eruptions can be accurately modeled is easily remobilised by wind producing over-thickened using gravity current models (Baines, in review; Sparks & lenses (D. Veres, pers. comm. 2011). In contrast, we Carey, 1991). At distance, ash is transported by ambient show that thicknesses in deep-sea cores remain relatively turbulence (Bursik et al, 1992). We attempt to constrain constant, with the exception of a small number of re- the transition from dispersal by gravity current to ambient worked sites. We find tephra grain size distributions are turbulence to provide greater insight into the dispersion of much less affected by depositional environment than ash from the Campanian Ignimbrite eruption. References The dynamics of intrusions into a densitystratified crossflow. Journal ofFluid Mechanics, in review.

SPARKS, R. S. J., CAREY, S. N . , SIGURDSSON, H . 1 9 9 1 . Sedimentation

BAINES, P. 2 0 1 2 .

BURSIK, M . I., SPARKS, R. S. J., GILBERT, J. S., CAREY, S. N . 1 9 9 2 .

Sedimentation of tephra by volcanic plumes: 1. Theory and its comparison with a study of the Fogo A plinian deposit, Sao Miguel (Azores). Bulletin ofVolcanology54,329-344.

Keywords: Email:

from gravity currents generated by turbulent plumes. SMmentology 3S, 8 3 9 - 8 5 6 .

explosive eruption, Campanian Ignimbrite, grain size distributions, deep sea cores

sam.engwell@bristol.ac.uk

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

A new and improved geochronological investigation on the ultrapotassic rocks of the Alto Paranaiba Igneous Province, South East Brazil M. FELGATE, J. Hergt, D. Phillips, J. Woodhead School of Earth Sciences, University of Melbourne, Parkville, Victoria, Australia

new more robust geochronology has been obtained for 12 kimberlites and 8 kamafugites from the APIP using a combination of dating techniques. In-situ U-Pb perovskite analysis has been coupled with Ar-Ar and Rb-Sr analysis of phlogopite separates. The new data provides a more precise time frame for the Cretaceous activity in the APIP, allowing the region to be divided into 2-3 previously unrecognised magmatic episodes. The results enable the testing of the previous hypotheses, where the most decorated model, the Trindade plume model (Gibson etaU 1995) is brought into question.

The Alto Paranaiba Igneous Province (APIP) plays host to an eclectic range of rare ultrapotassic rocks of Cretaceous age, most notably kimberlites and kamafugites. Previously a number of geochronological and geochemical studies have been undertaken in an attempt to ascertain the relationship (if any) between the rock types and the cause of this Cretaceous magmatic activity. Currently three models exist, however all models are based around different geochronological constraints obtained by outdated or inaccurate dating techniques. In order to test the proposed models a more robust and reliable geochronological data set is required. In this study a

References GIBSON, S. A., THOMPSON, R. N., LEONARDOS, O. H., DICKIN, A. P.,

MITCHELL, I. G. 1995, The Late Cretaceous impact of the Trindade mantle plume — evidence from large-volume, mafic, potassic magmatism in SE Brazil. Journal of Petrology 36,189229.

Keywords: Email:

APIR kimberlite, kamafugite, perovskite

nn.felgate@student.unimelb.edu.au

Geological Society of Australia Abstracts 104

25tln Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Extreme snow fall and snow melt in alpine Australia S. FIDDESi, A. PezzQi, V. Barras^ 1 School of Earth Sciences, University of Melbourne, Parkville, Victoria, Australia 2 ACCESS Earth Systenn Modelling, Centre for Australian Weather and Clinnate Research, Bureau of Meteorology, Docklands, Victoria, Australia

Extreme snowfall and snow melt events present a these events will be examined over a range of scales and by considerable danger to Australia's alpine industries, categorizing mountains regions by location and height. communities and ecosystems. Despite this, little is Examination of the individual mountains characteristics known about the atmospheric circulation associated with associated wdth extreme snow events may enhance our these events. An improved understanding of cold season understanding of why some areas miss out whilst others weather conditions affecting the alpine region can lead receive heavy snow. In addition to this, this research can to a safer and more prepared community. Historic snow also help us determine why some mountains may have a depth records for mountains across Victoria are analysed good snow season whilst others have an average or poor and extreme days of snow accumulation and melt have season. This part of the research will also take into account been identified. Using this, the characteristic synoptic local factors such as aspect, height and surrounding terrain circulation, wind and temperature patterns associated with and the evolution of extreme weather events. Keywords: Email:

snow, melt, extreme, alpine

s.fiddes@student.unimelb.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

A previously unrecognised major orogenic front in Argentina M. A. mCH\ M. G. Fuentes^, R Hasalova^, R. Becchio^, N. Hunter^, R. Weinberg^ 1 School of Geosciences, Monash University, Clayton, Victoria, Australia 2 Instituto Geonorte, Universidad Nacional de Salta, INENCO-CONICET, Av. Bolivia 5150,4400, Salto, Argentina

Ultramylonites are a result of high strain and strong strain zone consists of one kilometre of continuous ultramylonite. localisation. Consequently, they usually form centimetre- Thick sequences of high strain rocks can form through thick bands within sequences of rocks of lower strain. mass loss and high temperature recrystallisation (Hanmer This work describes a kilometre-thick ultramylonite zone etal.y 1995). However, protomylonites and ultramylonites in the Sierra de Quilmes of the Sierras Pampeanas in of the El Pichao shear zone are geochemically similar Argentina. The Sierra de Quilmes is a metamorphic indicating that ultramylonites are more likely to have complex that underwent deformation and anatexis during formed through high strain distributed over a wide area, the Famatinian orogeny 470 Ma). The complex was indicative of poor localisation processes. A thrust shear thrust to the SW on a mylonitic shear zone which contains zone of such high thickness and strain indicates the El a high strain zone at least 5 km thick, designated here the Pichao shear zone may represent a major orogenic front of El Pichao shear zone. The core of the El Pichao shear the Famatinian orogeny. References

Modest movements, spectacular fabrics in an intracontinental deep-crustal strikeslip fault: Striding-Athabasca mylonite zone, NW Canadian Shield. Journal of Structural Geology 17(4), 493-507.

HANMER, S., WILLIAMS, M. KOPF, C. 1995.

Keywords: Email:

ultramylonite, thrust shear zone. Sierras Pampeanas

melanie.finch@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Structural and sedimentological evolution of an Incipient transfornn continental margin: an example from the Valle Calamajue, Gulf of California, Mexico S. GOYEN, C. Seller, A, Gleadow, B. Kohn School of Earth Sciences, University of Melbourne, Porkviile, Victoria, Australia

The Ballenas transform segment of the Gulf of California, two antithetic normal faults that are parallel to and likely Mexico, provides a unique opportunity to study the associated with the transform fault. Clast imbrications evolution of a relatively young sheared margin. The consistently indicate NE-directed palaeoflow, suggesting Valle Calamajue is located on the eastern coast of that the topographic high of the fold hinge postdates central Baja California, adjacent to the Ballenas transform deposition of the conglomerate. The establishment of fault. Mapping in this region reveals a number of a NE-directed drainage system prior to the localization faulted and broadly folded pre- to syn-rift sedimentary of shear into the Ballenas transform severely limits the and volcanic units. The study area is dominated by amount of uplift that may have occurred along a more a large section of conglomerate that forms the current mature but now abandoned transform fault ~ 35 km further drainage divide ~ 4 km inland from the coast. Within this east. Our study indicates that there are significant area the strata dip consistently to either the NE or SW structural controls on deformation and uplift adjacent to indicative of a broad antiformal bulge with an upright transform faults that occur in addition to any thermal uplift NW-SE striking axial plane. The anticline represents an related to transform margin formation, and may dominate extension-perpendicular accommodation zone between the early topographic evolution of such margins. Keywords: Email:

transform margin, tectonics. Gulf of California

s.goyen@pgracl.unimelb.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Exploring the potential of speleothem palaeoclimate records from S. E, Australia H. E. GREENi, J. D. Woodheadi, J. C. Hellstromi, R. N. Drysdale^, R. Pickering^ 1 School of Earth Sciences, University of Melbourne, Porkville, Victoria, Australia 2 Departnnent of Resource Monagennent & Geography, University of Melbourne, Parkville, Victoria, Australia

Despite intense interest in the Earth's climate since the anchoring high resolution analysis of stable isotopes and last glacial termination, there remain large uncertainties trace elements of 14 Stalagmites from locations across regarding the exact causes, timing and spatial extent of South Eastern Australia contributes hugely to global the key events of this period. Many of the millennial scale paleoclimatic studies which consistently highlight the climatic fluctuations characterising the last deglaciation lack of records originating from Australia. The analyses are well established in records from the Northern provide valuable insights into climate variability of this Hemisphere, and to some extent from the high latitudes under represented region from the late Pleistocene to early of the Southern Hemisphere. However, deciphering the Holocene and along with a new, detailed paleoclimatic global response to these events has been hampered by the record this study has also re-analyzed the only existing coverage of existing proxy records and the accuracy of their speleothem record for the region, consequently eliminating associated chronologies. High resolution, radiometrically a key piece of evidence for a globally synchronous response dated records from the Southern Hemisphere are urgently to events of the last deglaciation. required to resolve this issue. The use of U-Th dating Keywords: Email:

speleothem, paleoclimate, southern hemisphere, record paucity

h.green4@student.unimelb.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Microstructural evidence for the origin of thicic ultramylonites: the El Pichao shear zone, NW Argentina N. J. HUNTER, R Hasalova, R. Weinberg School of Geosciences, Monash University, Clayton, Victoria, Australia

The El Pichao shear zone (EPSZ) in the Sierra de Quilmes, NW Argentina, is a 3-7 km thick, N-S trending, ductile shear zone exploiting the contact between low grade metasedimentary sequences and high grade migmatite sequences. Rocks within the shear zone are granitic, and deformation fabrics vary from protomylonite via mylonite to ultramylonite. Ultramylonite fabrics can reach extreme thicknesses of 1km, which has been seldom observed elsewhere. Thus, the EPSZ provides a unique opportunity to understand thick ultramylonite formation and expand important geological discussions on strain accommodation and crustal movement. The mylonite sequences contain a banded matrix with coarse Qtz ribbons, micaceous bands and feldspar porphyroclasts (>2cm). In contrast, ultramylonite sequences contain a finer-grained equigranular matrix with feldspar porphyroclasts and a weak foliation defined by micas. A high degree of clast rotation is suggested by numerous Keywords: Email:

5-porphyroclasts and the flow planes of micas in the matrix of each mylonite type. The homogenisation of the matrix from protomylonite to ultramylonite is suggested by grain size reduction and an increased mixing of phases. Quartz crystallographic-preferred orientation (CPO) data demonstrate a marked transition from strong CPO fabrics to weak random fabrics within the ultramylonite range, which appears to be strongly related to the degree of matrix homogenisation. We argue based on CPO data and textural features that the formation of thick ultramylonite sequences in the EPSZ resulted from the homogenisation of an initially anisotropic matrix, facilitated in part by intense clast rotation. This optimised a switch from dislocation creep to diffusion creep accommodated grain boundary sliding as the key deformation mechanism. The loss of effective slip planes in the resulting homogeneous matrix meant that strain could not be well localised and thus the ultramylonite deformed as a thick body.

shear zones, mylonitisation, strain accommodation, deformation, crystallographic preferred orientation (CPO)

nicholas.hunter@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

The petrology, geochemistry and geochronology of the Middledale Gabbroic Diorite, New South Wales K. ILES School of Earth Sciences, University of IVlelbourne, Parkville, Victoria, Australia

All studies employing zircon U-Pb age information, Hfisotope analyses, or oxygen isotope data, require the calibration of instrumentation using well-characterised zircon reference materials that are ideally homogeneous on submicron and larger scales and in abundant supply. The Middledale Gabbroic Diorite (MGD) in New South Wales host one suite of such reference materials, the internationally distributed zircon standard TEMORA 2 and its prototype standard, TEMORA 1. The MGD has been found to be petrographically and geochemically heterogeneous. A combination of variable grainsize, textures, mineralogy and extent of alteration (particularly of clinopyroxene and hornblende) has led to the identification of different lithologies within the pluton. It has been observed that although TEMORA 1 and TEMORA 2 have the same U-Pb ages, they are variable in oxygen isotopes (51^0 = 0.79-0.82%); furthermore, they have similar bulk-rock Zr concentrations, but the more altered Keywords: Email:

TEMORA 2 host rock has an order of magnitude more zircon. Additionally, this study has revealed coherent magmatic geochemical trends, and a closed system with respect to mobile elements. Laser ablation ICPMS trace element data of minerals in thin section are used to investigate the link between increased alteration and higher zircon abundance. New U-Pb SHRIMP ages confirm the uniformity of the zircon in this respect across the pluton and reaffirm the value of TEMORA 2 as a geochronology standard. Forthcoming zircon O isotope data (using SHRIMP II) and Hf isotope data (using laser ablation multicollector ICPMS) will uncover the extent of pluton-wide heterogeneity of these elements, and investigate the role of magma mixing and late stage alteration have played in causing the variability. These results have implications for the validity of the zircons as reference materials for O and Hf isotope studies.

TEMORA zircons, U-Pb geoclnronology, O isotopes, Hf isotopes

klles@student.unlnnelb.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Modelling surface- and groundwater mixing of the bank storage and hyporheic zones 1 C- S. LAI, I. Cartwright, H. Hofmann School of Geosciences. Monash University, Clayton, Victoria, Australia

In the gaining reaches of meandering streams, such as the lower Avon River, Gippsland, various processes may complicate the overall picture of groundwater-surface water interactions. Two of these are hyporheic exchange and bank storage. These processes are intrinsic towards understanding the water balance, nutrient processing and contaminant transport. With gaining status, regional groundwater usually flows towards the river, but is reversed during floods by bank storage. Various hyporheic exchange flowpaths may exist, including parafluvial shortcut flow through gravelly point bars inside meanders. Such flowpaths reduce the distance, and may be an important contribution to the flow vector field. With low ^^^Rn activities close to the river, especially near the north end, this shortcut was hypothesised to be important.

Keywords: Email:

Numerical modelling in Visual MODFLOW indicates that the perpendicular regional groundwater flow is dominant, but a short duration of a potential flood-induced shortcut occurs during the recession. MT3DMS was used to determine the dimensions of the Woessner hyporheic zone, which expands perpendicularly in response to the flooding. Many parameters can be altered to modify the size of the hyporheic zone, but only systematic riverparallel oriented higher hydraulic conductivity can alter the shape to produce a possible shortcut. Thus, the shortcut is considered unlikely. This is attributed to how groundwater is slow, the boundary conditions used, and that bedforms are more important drivers of hyporheic exchange instead of gentle meanders.

groundwater surface-water interaction, numerical modelling, hyporheic exchange, bank storage, meander

eamon.lai@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

The formation of the pinnacles in Nambung National Park, Western Australia M. LIPAR, J. Webb Environmental Geoscience, Departnnent of Agricultural Sciences, La Trobe University, Bundoora, Victoria, Australia

The pinnacles in Nambung National Park in south-western cemented filling of solution pipes, focused cementation or coastal Western Australia are calcarenite pillars up to 5 m trace fossils of trees. However, based on detailed field work, high and up to 3 m wide, with various shapes: conical, morphometrical analysis of the pinnacles, thin section cylindrical with rounded top, mushroom-like, and multiple examination, and mineralogical, chemical and isotopic peaks. They occur in dense fields with an average spacing analysis of rock samples, microbial cementation appears between 0.5 m and 5 m, and the pinnacle tops often define to be one of the dominant process of lithification, i.e. the a horizontal surface that decreases in direction northwards. pinnacles are also organosedimentary structures. Calcrete The pinnacles have been described as a syngenetic development and karstic weathering have subsequently karst feature and interpreted as either residual features modified the pinnacle shapes. resulting from widening and coalescence of solution pipes. Keywords: Email:

karst, syngenetic, pinnacles, calcrete, calcarenite

nnlipar@students.latrobe.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Simulation of the meteorological effects of the S Fornacis superflare on Earth T. LOUGHRAN, K. Walsh School of Earth Sciences, University of Melbourne, Porkville, Victoria, Australia

Short duration stellar flares that are many times larger than those that occur on the Sun have been observed on stars that are remarkably similar to our Sun. One particularly large example of these "Superflares" occurred on the star S Fornacis on 2 March 1899 and is estimated to have had a total flare energy output 10,000 times greater than an average superflare. A superflare this size could have some serious effects on any planets that are in close orbits within the habitable zone. These effects might include, but are not limited to, large scale melting of ice and storm Keywords: Email:

superflare, radiation, planetary climates

tammasfl@student.uninnelb.edu.au

development. In this study the potential weather and climate effects that a superflare would have on Earthlike planets is investigated using the CSIRO Mk3L climate system model. A method for calculating the evolution of the radiation at the Earth is presented as well as some preliminary simulations of a planet identical to Earth experiencing the S Fornacis superflare. The differences of prognostic variables such as precipitation and temperature over both land and ocean surfaces is shown as well as changes in icy surfaces.

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

A combination of radiogenic and innpact heating to form Type 7 ordinary chondrite meteorites E. MARE, A. Tomkins School of Geosciences, Monash University, Clayton, Victoria, Australia

Ordinary chondrite (OC) meteorites are sourced from asteroids that were thermally metamorphosed due to the decay of short-lived radioisotopes. 'Petrologic Types' from 3-7 are assigned to OC meteorites, describing progressive stages of metamorphism. Thermal models have shown that Types 3-6 formed at different depths within an asteroid due to radiogenic metamorphism, but no consensus has been reached about the formation of the rare and controversial Type 7s. In this study, we use thermal modeling to investigate the formation of Type 7 meteorites by radiogenic heating, impact heating, and a combination of the two. Radiogenic heating would lead to a core zone of Type 7, while impact heating could form Type 7s either Keywords: Email:

in a contact aureole under an impact melt sheet, or by localized heating within the parent body. We found that the Type 7 meteorites cannot represent a core zone in an OC parent body because the model leads to faster cooling rates of Type 6 meteorites than are observed. Impact heating on a cold asteroid cannot raise temperatures high enough to form Type 7 meteorites. However, impact heating on a parent body that was already warm due to radiogenic heating could possibly explain these Type 7 meteorites. If further work can support this hypothesis. Type 7 meteorites show that a combination of radiogenic and impact heating affected the OC parent bodies.

ordinary chondrites, Petrologic Type, thermal modeling, thermal history

eleanor.mare@monash.edu

Geological Society of Austraiio Abstracts 104

25th Victorian Universities Eartin and Environmental Sciences Conference Monash University, 25 October 2012

How do we explain a U-REE deposit like Valhalla? Unusual rare metal-enriched mineralisation and its implications for ore-forming fluids M. McGLOIN, A. G. Tomkins, R. Weinberg School of Geosciences, Monash University, Clayton, Victoria, Australia

The Valhalla uranium-rare earth element (U-REE) deposit of the Mount Isa Inlier, Queensland, is unusual for its enrichment in incompatible and immobile elements (Y, Zr, REE and P) but several peculiar geochemical and mineralogical anomalies have not previously been recognised. Various conflicting genetic models for the UREE prospects have failed to provide evidence of a source rock for such mineralisation. New data may help to constrain a genetic model further. We demonstrate the Valhalla deposit has (1) significant fluorine enrichment within fluorapatite in the ore zone (> 1 % F); (2) abundant carbonate minerals with isotopic signatures that suggest the influence of a magmatic source; (3) rare uraniumzirconium silicates associated with the main ore phase (> 4 % Zr); and (4) extremely low geochemical Th/U ratios of < 0.5, even compared with typical uranium deposits. Based on the four new data sets outlined above and using classic partition coefficient fluid data for U, Zr, Th and

Keywords: Email:

Cu, we place some important controls on ligands in the fluids that formed the main phase of mineralisation at Valhalla. High ore zone zirconium content requires the presence of fluoride as ZrF(0H)3 or ZrF2(OH)2 complexes. Uranium can be mobilised by either fluoride or chloride species, however fluoride is more effective. Thorium is also mobilised by fluoride species, but remains immobile for chloride species. The extremely low Th/U ratio of the Valhalla deposit can be explained by C02-rich fluids, which immobilise thorium but allow uranium mobility. A chloride-rich fluid cannot explain the low Th content of Valhalla, because minor copper mineralisation in the deposit shows no statistical correlation with uranium, precluding a relatively oxidized fluid and suggesting a reduced fluid was a necessary requirement. We suggest nearby highly fractionated granites as the most likely source for many of the important ore-forming fluid components.

uranium, ore-forming fluids, incompatible, immobile elements

matthew.mcgloin@m.onash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

City and country scale COj fossil fuel trends from a very high resolution global dataset A. D. McROBERT, R Rayner School of Earth Sciences, University of Melbourne, Parkville, Victoria, Australia

CO2 emissions from fossil fuels are the main driver of Using a linear least-squares regression model, the most the enhanced greenhouse effect. Considering this, it interesting (both positive and negative) trends on the world is surprising how little is understood about when and have been chosen for further investigation. Some very where the emissions originate at fine resolution. This large positive trends were found in vast areas around research aims to describe the global trends in fossil fuel Beijing and Shanghai, while small negative fossil fuel trends emissions at a resolution of 0.1°. To investigate this, were observed in the greener cities of Western Europe. an 18 year (1992-2010) world dataset of yearly averaged The errors on each individual pixel are relatively large CO2 greenhouse gas emissions was used (Rayner et al but can be reduced with ^^CO^ measurements. Better 2010). The dataset is derived by combining national energy understanding of where and when CO2 emissions are data, data on individual power-plants, gridded data on created could shape the direction of future fossil fuel population and night-time lights as measured by satellite. reduction policies. References RAYNER, R, RAUPACH, M., PAGET, M., PEYLIN, R, KOFFI, E. 2 0 1 0 .

A new global gridded data set of CO2 emissions from fossil fuel combustion: Methodology and evaluation. Journal of Geophysical Research 115, D 1 9 3 0 6 , d o i : 1 0 . 1 0 2 9 / 2 0 0 9 J D 0 1 3 4 3 9

Keywords: Email:

CO2, fossil fuels, global warming, nightlights

nncrobert@student.uninnelb.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Investigating impacts of vegetation type on groundwater recharge in the IVIurray Darling Basin J. NOORDA, M. Currell School of CiviL Er^vironnnental and Chennical Engineering, RMIT University, Melbourne, Victoria, Australia

The Murray-Darling Basin Authority describes the Murray- on groundwater recharge is the depth to the ground Darling Basin (MDB) as an integral part of the ecological water. The depth and time lag for recharge to reach and economical health of Australia. Agriculture in the the water table makes it impractical to use piezometric MDB is essential for food provision; however activities techniques in some areas. Groundwater modelling is such as land clearing and irrigation are threatening the a very useful tool to investigate impacts of vegetation environment and the ongoing viability of agriculture. This changes. MODFLOW is the most widely used program to investigation looked at how changing vegetation types model groundwater system. However to capture impact of impacts groundwater recharge in the MDB. Stripping vegetation changes which occur mainly in the unsaturated native vegetation was found to impact the groundwater zone it was recommended that MODFLOW be coupled recharge by changing the rate of evapotranspiration with a model of the unsaturated zone such as SWAP. A and the mechanism of groundwater recharge. The conceptual model of the Loddon river catchment was consequences to the water table level depended on the developed which could be used to build a numerical model geology, climate and new vegetation type. One difficulty to further investigate this issue. identified in monitoring the effect of land use changes Keywords: Email:

groundwater, Murray-Darling Basin, Loddon River

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Geology overshadows the effect of land use change: a paired catchment study In Southwestern Victoria, Australia F. PERVEENi, J. Webbi, E. DreseP 1 Environnnental Geoscience, Departnnent of Agricultural Sciences, La Trobe University, Bundoora, Victoria, Australia 2 Departnnent of Prinnary Industries, Future Farnning Systenns Research Division, Victoria, Australia

Southwestern Victoria has undergone significant duration curves constructed for the three catchments show conversion of farm land to commercial plantations that the southern farm catchment rapidly loses surface of Eucalyptus globulus, and this has been of concern run-off after rainfall events, and does not show any longas it is suspected to have adverse effects on surface lasting, lowflows.The rainfall-run-off ratio for the southern and groundwater resources, because woody vegetation farm catchment was 10 times lower than in the adjacent commonly uses more water annually than grasses and northern farm catchment, though the two catchments have non irrigated agricultural crops. Department of Primary similar climate, vegetation and topography. The differences Industries (DPI), Victoria, started a detailed paired may be attributed to subsurface karst terrain beneath the catchment study, in collaboration with La Trobe University, southern farm catchment, which captures a large portion to assess the likely impact of tree plantations on water of the surface flow and diverts it underground. The stream resources of southwestern Victoria. We present here in the plantation catchment shows a quicker response the results of hydrological investigations of three small compared to the streams in the farm catchments, but any subcatchments of Crawford River, established exclusively differences due to the presence of the tree plantation are for this paired catchment study. Streamflow from the relatively small, and are overshadowed by the geological studied catchments was dominated by storm flow. Flow differences between the catchments. Keywords: Email:

Southwestern Victoria, paired catchment study, stream hydrology, rainfall-runoff ratio, flow duration curves

fperveen@students.latrobe.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

The Late Cretaceous environment: unearthing evidence for changes in dinosaur diversity, Alberta, Canada A. QUINNEYi, F. Therrien^, D. Zelenltsky^ 1 School of Geosciences, Monash University, Clayton, Victoria, Australia 2 Royal Tyrrell Museunn, Drunnheller, Alberta, Canada 3 Deportnnent of Geoscience, University of Calgary, Calgary, Alberta, Canada

The Upper Cretaceous Horseshoe Canyon Formation palaeoenvironmental and palaeoclimatic conditions of the (HCFm) of Alberta, Canada preserves a diverse assemblage HCFm can be achieved through the study of paleosols, or of fossil vertebrates that was subject to a localized faunal ancient soils, that are preserved in the rock record. Because turnover across the Campanian-Maastrichtian boundary. the HCFm was deposited in a terrestrial setting, it has Some authors have attributed this dramatic change in preserved numerous paleosols throughout its stratigraphic faunal composition to climate change citing changes interval. Detailed study of the lithological and geochemical in palynology, lithology, and palaeontology through the features of HCFm paleosols have provided a record of HCFm as evidence. Based on these lines of evidence, these palaeoenvironmental and palaeoclimatic change from the authors have suggested that cooling and drying throughout late Campanian (73 Ma) to the early Maastrichtian (67 Ma). the HCFm are responsible for: (a) the disappearance Comparisons between the faunal turnover and the paleosol of most ceratopsian dinosaurs and the ankylosaur record reveal a more complex relationship between the Edmontonia, and (b) the replacement of the hadrosaur faunal assemblage and episodes of palaeoenvironmental Edmontosaurus by the hadrosaurs Hypacrosaurus and and palaeoclimatic change than was previously thought. Saurolophus and by the basal ornithopod Parksosaurus. The results suggest that the Late Cretaceous terrestrial Claims associating climate change with the faunal turnover, vertebrate fauna of Alberta was more sensitive to changes however, have not been tested by means independent in environmental conditions than to changes in climatic of lithology or fossil occurrences. Reconstruction of the conditions. Keywords: Email:

faunal turnover. Cretaceous, paleosol, palaeoclimate, palaeoenvironment

ann.quinney@nnonash.edu

Geological Society of Australia Abstracts 104

25th Victorian Ur^iversities Earth and Environmental Sciences Conference IVIonash University, 25 October 2012

A contribution to the understanding of the eruptive behaviour of Somnna-Vesuvius; a mineral chemistry perspective D. RED|12, L V. Danyushevkyi, A. Lima^, B. De Vivo^ 1 School of Earth Scier^ce, University of Tosnnania, Hobort, Tosnnania, Australia 2 School of Earth Science, University of Naples "Federico 11", Naples, Italy

The Somma-Vesuvius volcanic system resides in one of peculiar potassium and high-potassium magmatism with the most controversial and complex geological settings in different degrees of silica under-saturation, as well as the Mediterranean region. It is among the most studied the threat that the volcano represents for around one volcanoes in the world and the first one whose eruptive million people living around its slopes, have been the activity has been documented since the historic Plinian main reasons for continuing research focus. Chemical eruption of Pompeii (79 AD); an extensive literature covers characterization of pristine mineral phases such as olivines such diverse aspects as origins, volcanic activity, tectonic and clinopyroxenes derived from lavas and pyroclastic settings, petrography, petrology and geochemistry, leading deposits of the last 25 kyr of the volcano activity is used as to a large range of interpretations concerning the internal a novel approach to understanding the difference between structure of the volcano, its eruptive behaviours and the the main explosive Plinian events and the smaller effusive magmatic source. Despite a significant effort, there is Interplinian ones. I will present the initial results of these currently no agreement on the causes of the eruptive analyses performed on a set of samples collected from behaviour of the volcano which in the last 25 kyr produced different eruptive units of Somma-Vesuvius covering the alternately Plinian to Strombolian-Vesuvian eruptions. The last 25 kyr. Keywords: Email:

Vesuvius, K-HK magmatism, Plinian eruption, clinopyroxene, olivine

dredi@utas.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

The effect of lake loading on groundwater levels around Lake Tutchewop In the Murray-Darling Basin, southeastern Australia T. ROBSON, J. Webb Environnnental Geoscience, Departnnent of Agricultural Sciences, La Trobe University, Bundoora, Victoria, Australia

The Murray-Darling Basin, which provides 80 % of Australia's $28.3 billion irrigated agriculture industry, has the Murray River as its major drainage outlet, and management of salt loads in the river is required to ensure the agricultural viability of the basin. One available management option is to divert the saline groundwater flowing towards the Murray River using salt interception schemes. Lake Tutchewop, a salt evaporation basin within one of these interception schemes, has received about one million tonnes of salt since 1968. The piezometers drilled around the lake to monitor the groundwater and investigate the fate of the added salt have many years of monthly water level measurements, making them ideal for stochastic time series modelling. Because the addition of saline disposal water to the lake is often not synchronous with rainfall events, the impact of lake loading on surrounding groundwater levels is relatively easy to distinguish, unlike for many lakes. The predefined impulse response function in continuous time Keywords: Email:

(PIRFICT) model was applied to the available data using the commercially available program Menyanthes. The PIRFICT model is a transfer function noise (TFN) model that is able to handle input and output data with different observation frequencies. The input variables (rainfall, FAO-56 evapotranspiration, pan evaporation and lake levels) were tested in double and triple input models. The results showed that for bores within ~ 7 km of the lake, triple input models vdth lake level, rainfall and FAO-56 evapotranspiration produced better results than models using rainfall and evapotranspiration only; this effect extends to a maximum depth of ~ 70 m below the lakebed. The response in groundwater levels to lake level changes is due to a pressure response rather than movement of saline disposal water. The results indicate the importance of quantifying surface water responses in groundwater systems, and this is also of value in determining the management options for saline disposal basins.

lake loading, groundwater dynamics, groundwater- lake water interaction, saline disposal basin

tcrobson@students.latrobe.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

"UP, DOWN ... MORE ENERGY!!!" — The dynamics of magmatic sulfide liquids B. M. SAUMUR, D. Boutelier, A. R. Cruden School of Geosclences, Monash University, Clayton, Victoria, Australia

Sulfide liquids represent a volumetrically small portion of magmatic systems, but are responsible for the formation of orthomagmatic Ni-Cu-PGE sulfide deposits. Compared to silicate melts, immiscible magmatic sulfide liquids have lower viscosities (by 1-3 orders of magnitude), higher densities (>1500kg/m^) and lower solidus temperatures (> 150 °C lower). These properties hinder the withdrawal of sulfide liquid from magma staging chambers and its ascent to higher structural levels, and allow for late-stage mobility and downward percolation along grain boundaries and fractures within wall rocks. Upward or lateral withdrawal of sulfide from a magma chamber can occur by viscous entrainment within relatively buoyant (mafic) magma. Analytical solutions (e.g., Blake & Ivey, 1986) applied to mafic-sulfide systems predicts that significant draw-up of sulfide liquid within mafic magmas can occur at high flow rates (10-1000 m^/s), at reasonable Reynolds (> 1000) and Weber numbers (0.07-700). At lower flow rates and Re draw

up is hindered by interfacial tension, as indicated by the low capillary numbers of the system. Preliminary results from new analogue modelling suggest that the viscosity ratio between the silicate and sulfide melt plays a particularly important role during vdthdrawal. In fractured systems sulfide percolation (i.e., backflow) is strongly controlled by the height of the sulfide column, because a higher vertical body force is generated if the fluid remains interconnected. To enter a fracture, the fluid must overcome a capillary pressure which is inversely proportional to the width of a fracture; thinner fracture v\ddths can be intruded as a body of dense fluid percolates downwards. Such a process, along VNdth late stage mobility of sulfide liquids, could explain the presence of thin (centimetre to metre sized) massive sulfide injections into wall rocks observed at Ni-Cu deposits such as Voisey's Bay (Labrador, Canada), Eagle (Michigan, USA), and Sudbury's late offset dykes.

References BLAKE, S., IVEY, G. N. 1986. Magma-mixing and the dynamics of

withdrawal from stratified reservoirs. Journal of Volcanology

and Geothermal Research 27,153-178.

Keywords: Email:

Ni-Cu-PGE sulfide deposits, analogue modelling, magma systems, fluid dynamics

benoit.saumur@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Cranial form and function in the largest ever nnarsupial, Diprotodon optatum: a comparative finite element analysis A. SHARP School of Geosciences, Monash University, Clayton, Victoria, Australia

The extinct Diprotodon optatum was the largest ever as a grazer/browser has an intermediate tolerance to marsupial. Despite its large size, the skull of Diprotodon stress compared to wombats and koalas. The extensive is remarkably fragile, composed of thin cranial bone and sinuses also helped to dissipate stress over the cranium in extensive endocranial sinuses. The extent of the sinuses Diprotodon compared to both the wombat and koalas. In is unlike any seen in other extinct or extant species, addition to FEA, a quantitative analysis was undertaken to and therefore, the function of such a structure, is not determine the extent of the sinus volume and brain volume obvious. In this study a functional analysis of the skull of Diprotodon in comparison to small and large marsupial was undertaken to assess its mechanical performance and placental mammals. These results indicate that during biting. To identify areas of high and low stress, Diprotodon has one of the most extensive sinus networks a finite element analysis (FEA) was performed on a in the animal kingdom. Further examination of the cranial three dimensional model of the skull. Comparisons structure and manipulations to the 3D model will likely were undertaken with other marsupials, including the provide additional insights concerning distribution and common wombat (Vombatus ursinus), a grazer, and koala tolerance of stress, the efficiency of the skull structure, the {Phascolarctos cinereus), a browser. The results correlate function of the extensive frontal sinuses and the behaviour with the feeding behaviour of these animals; Diprotodon and ecology of Diprotodon. Keywords: Email:

finite element analysis, megofauna, sinus

alana.sharp@monash.edu

Geological Society of Australia Abstracts 104

25tln Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

The eruption history of the Pre Lower Pumice 1, Lower Pumice 1 and Lower Pumice 2 eruption sequences, Santorini, Greece J. SIMMONSi, R. A. F Casi, C. Folkes^, T. Druitt^ 1 School of Geosciences, Monash University, Clayton, Victoria, Australia 2 Observotoire de Physique du Globe de Clernnont-Ferrand, Universite Blaise Pascal, Clernnont-Ferrand, France

Over 650 kyr, the Santorini volcano has experienced 12 1 pyroclastic fallout (LPl-A), ignimbrite (LPl-B) and comajor explosive eruptions and preserves the remnants of ignimbrite lag breccia (LPl-C) deposits. A paleosol lava shields, lava-dome complexes, stratovolcanoes and separates this sequence from the overlying Lower Pumice explosive calderas. These eruptions collectively define two 2, pyroclastic fallout (LP2-A), pyroclastic flow and surge mafic to silicic magmatic cycles, each terminating with (LP2-B), ignimbrite (LP2-C) and co-ignimbrite lag breccia

a large caldera collapse event. The most recent 3.5 ka (LP2-D) deposits. The deposits of the Lower Pumice 1 and Minoan explosive eruption was responsible for the demise Lower Pumice 2 eruptions each represent the formation of the Minoan civilisation at Santorini and terminated of, and subsequent collapse of, a plinian style eruption the second magmatic cycle. The Pre Lower Pumice column. Co-ignimbrite lag breccias, which terminate 1, Lower Pumice 1 (200 ka) and the Lower Pumice 2 each eruption sequence, represent the peak, in volcanic (180 ka) eruptions terminated the first magmatic cycle, intensity, of each eruption. These breccias could represent and are dacitic to rhyolitic in composition. The Lower a single caldera collapse event, resulting from incremental Pumice 2 eruption is considered analogous to the Minoan collapse and caldera floor subsidence, throughout the eruption. Hence, these eruptions are potentially important Lower Pumice 1 and Lower Pumice 2 eruptions. A high for understanding cyclicity in magma generation processes angled unconformity, which truncates the Lower Pumice 2 and subsequently, hazard mitigation. This current and underlying eruption sequences, supports this concept. research reveals a more complex history for the Lower Alternatively, each breccia could represent a discrete Pumice eruption sequences than previously thought. The caldera collapse event, coinciding with the Lower Pumice Pre Lower Pumice 1 succession consists of 13 small 1 and Lower Pumice 2 eruptions respectively. However, volume fallout, surge and ignimbrite deposits. These no other field relationships, supporting an isolated Lower deposits are disconformably overlain by Lower Pumice Pumice 1 caldera collapse event, have been observed. Keywords: Email:

Santorini Volcano, Pre Lower Pumice 1, Lower Pumice 1, Lower Pumice 2

jack.simmons@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Neutralisation of alumlnlum-rlch acid mine drainage to form a magnetic sludge W. STANFORD, J. Webb Envlronnnental Geoscience, Departnnent of Agricultural Sciences, La Trobe University, Bundoora, Victoria, Australia

The active remediation of acid mine drainage (AMD) typically employs hydrated lime as the neutralising agent, and forms a voluminous sludge. Sludge composition varies depending on initial AMD chemical composition and the neutralising process utilised. The most desirable outcome is to form a high density sludge (HDS) consisting of magnetite, as this is cost effective, relatively low volume and resistant to leaching. Previous studies have shown that aluminium in AMD is detrimental to the formation of magnetite, favouring less stable iron oxy-hydroxides such as ferrihydrite and schwertmannite. The focus of this study was to develop a procedure to neutralise AMD containing aluminium and produce a HDS composed of magnetite. A small (4.5 L) batch treatment process was utilised, using a typical AMD composition incorporating high soluble metal concentrations (Al, Cu and Zn). Aluminium solubility Keywords: Email:

is strongly determined by pH, and at normal surface temperatures it precipitates as amorphous aluminium hydroxide at pH between 4.5 and 5.0. During the experimental neutralisation of AMD, pH was stabilised at pH ~ 4.7 for variable times prior to complete neutralisation, to assess the optimal time for aluminium precipitation to occur. Ongoing analysis indicates that 10 minutes is sufficient for aluminium precipitation to occur at this experimental volume; neutralisation of the Al-free AMD then produces a magnetite sludge. Batch tests were also run to ascertain the ratio of ferrous versus ferric iron in the AMD required for successful production of a magnetic high density sludge. Preliminary results suggest that a ferrous component less than 75 % of total dissolved iron content inhibits the formation of magnetic HDS, rather favouring production of amorphous ferric oxy-hydroxide sludges.

acid mine drainage, aluminium, magnetite

wjstanford@students.latrobe.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference IVIonash University, 25 October 2012

Silicate partial melting in ttie early solar system: origins and mectianisms for crustal melt migration on ttie H-Chondrite parent body A. W. TAIT School of Geosciences, Monosh University, Clayton, Victoria, Australia

The depth and process of crustal melt formation in planetesimals is poorly understood, due to scarcity of samples that exhibit chondritic and achondritic textures. To address this Watson012, a H7 chondrite, was examined and compared with metamorphic contact aureoles on Earth. Optically continuous plagioclase and LPO data suggests that the plagioclase is a single large poikilitic grain. Along with the absences of glasses and granophyres, this poikilitic plagioclase indicates that the sample cooled at depth within the parent body. Watson012 exhibited textures consistent with partial silicate melting, including wetting of silicate melt phases and equilibrated 120° triple junctions. The interpretation of partial silicate melt is consistent with two-pyroxene thermometry, which measured a closure temperature of 1058 °C, that is just below the modeled silicate solidus of ~ 1066 °C. Due to silicate equilibration, the peak temperature is assumed to Keywords: Email:

be higher. Bulk REE and 2D modal analysis indicated that ~ 12 vol% silicate melt had been added to the sample and 4.4% metal/sulfide melt had been lost. Both melt phases used the same channels during transport. The amount of melt flux in the system indicates Watson012 was in the presence of a gravitation gradient. As such this rules out a core of H7 type material, as the gravitation gradient in the centre of the parent body would have been zero. Watson012 is interpreted as a region of radiogenically heated H6 material located at considerable depth in the parent body, which underwent localized partial melting due to a large shock event. Due to the insulation of depth, the temperature remained above the solidus long enough for melt to migrate a calculated distance < 1 km. This could explain the lack of basalts and magmatic iron associated with the H-Chondrite parent body.

anatexis, migmatite, H7, differentiation

alastair.tait@nnonasln.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference IVIonash University, 25 October 2012

Polycrystalline diamonds and associated intergrowth minerals from the Orapa Icimberlite, Botswana J. TESKE School of Earth Sciences, University of Melbourne, Parkville, Victoria, Australia

The Orapa mine in Botswana is a largely unique deposit set apart from most others by its dominance of eclogitic diamond inclusions over peridotitic ones and the large percentage (> 60 %) of polycrystalline diamond aggregates it produces. A number of aggregates contain intergrowth minerals, an uncommon occurrence in other polycrystalline diamond populations. The formation process of Orapa polycrystalline aggregates and how they differ to single crystalline diamonds is currently poorly understood, as the focus of previous studies predominantly have been on inclusions in single crystalline diamonds. Polycrystalline diamond morphologies display a wide variation in the degree of resorption caused by kimberlite magma. Typically peridotitic samples contain smaller crystals exhibiting less resorption than the eclogitic and websteritic ones. Intergrowth garnet mineral chemistry overlaps v^th garnets from Orapa diamond inclusions and eclogite xenolith minerals. Peridotitic garnet intergrowths are Iherzolitic in composition and characterised by variable

CaO (3.67-5.51 wt%) and ^ 2 0 3 contents (0.82-3.8 wt %). Eclogitic garnets display variable CaO (3.83-5.29 wt%) with low Cr203 contents (<0.2wt %). Websteritic garnets exhibit a transitional chemistry. Some Peridotitic Crdiopsides display inhomogeneous mineral chemistry indicating alteration either with kimberlite magma or due to cleaning processes in the mine. Cr-diopsides with homogeneous mineral chemistry were used for thermobarometric calculations resulting in temperatures of 7 4 5 - 9 7 6 °C and pressures of 3 2 - 4 6 kbar. Compared with temperatures (1135-1212 °C at an estimated pressure of 50 kbar; Gurney et al 1984) of diamond inclusions from Orapa, conditions recorded by intergrowth minerals are noticeably lower and do not fall v\dthin the diamond stability field. The samples in this study indicate that interaction v\dth the kimberlite magma has taken place, and Cr-diopside thermobarometry suggests re-equilibration of mineral chemistry has occurred in response to cooling mantle conditions.

References GURNEY J. J., HARRIS J. W., AND RICKARD R. S. 1 9 8 4 .

Silicate a n d

oxide inclusions in diamonds from the Orapa mine, Botswana. In Proc.: Kornprobst, J. (Ed.), 3rd Int. Kimberlite Conf., Kimberlites II: The Mantle and Crust-mantle Relationships, pp. 3-10. Elsevier, Amsterdam.

Keywords: Email:

polycrystalline diamonds, intergrowth minerals, thermobarometry

jessie.teske@uqconnect.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Deposit characteristics of blocic and ash pyroclastic flows, and comparison with debris flow deposits: the 1990-1995 Mount Unzen Eruption (Heisei Shinzan), Kyushu, Japan D. UEHARAi, R. A. R Casi, C. Folkesi, S. Takarada^ 1 School of Geosciences, Monash University. Clayton, Victoria, Australia 2 Geological Survey of Japan, Notional Institute of Advanced Industrial Science and Technology (AIST), Tsukubo, Iboroki, Japan

Mount Unzen is a polygenetic dacitic composite deposits are very poorly sorted, massive, normal and/or stratovolcano located on the Shimabara Peninsula, reverse graded, ash poor and contain angular to rounded Nagasaki Prefecture, Kyushu, south western Japan. The clasts. Hyperconcentrated flood flow deposits are very most recent eruption occurred between 1990-1995 where similar to surge deposits as both contain cross bedding and successions of lava dome collapses during the five year laminations features, they are moderately to well sorted period produced 13 lava domes, approximately 9800 block and are ash rich. Pyroclastic fallout deposits (co-ignimbrite and ash pyroclastic flows and killed 44 people. Five and Vulcanian plume related fallout) are well sorted, ash major deposit types were produced during and after the rich and have uniform bed thickness. Distinguishing eruption: block and ash flow, debris flow, pyroclastic surge, block and ash and debris flow deposits at Mount Unzen hyperconcentrated flood flow and fallout deposits. The is very difficult in the field especially when close to the block and ash flow (BAF) deposits consist of block sized volcano (less than 2 km from summit). Currently the main lava dome fragments and ash of the same composition criteria used to distinguish block and ash and debris flow (monomictic). The deposits are very poorly sorted, deposits include: clast shape and angularity, carbonised massive, reverse and/or normal graded, and contain versus non-carbonised vegetation material and lower ash angular to subrounded clasts. Pyroclastic ash cloud surge proportions in debris flow deposits. Similarly there are deposits are better sorted (moderately sorted) compared to problems distinguishing pyroclastic surge deposits from block and ash flow deposits and are lapilli-ash rich. Debris hyperconcentrated flood flow deposits. Currently there is flow deposits consist of remobilised block and ash flow no diagnostic feature to distinguish the two deposit types. deposit material and minor country rock material. The Keywords: Email:

Mount Unzen, block and ash flows, debris flows, hyperconcentrated flood flows

dan.uehara@nnonash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Structural interpretation through implicit 3D geological modelling S. A. VOLLGGERi, A. R. Crudeni, E. J. Cowan^ School of Geosciences, Monash University, Clayton, Victoria, Australia Orefind Pty. Ltd., Frennantle, Western Australia, Australia

Tectonic processes and the resulting deformation of shells, lithological boundaries or structural trends. These Earth's crust are well known to control and influence isosurfaces can also be used to define ore bodies and obtain the location and shape of ore bodies. Furthermore, their geometries, grade continuity direction (s) and their ore body geometries and their associated spatial spatial relationship to lithological boundaries and major relationships provide fundamental clues to the genesis structures. Subsequently, working hypotheses based on of ore deposits. It is therefore important to establish the geometrical analysis of the initial 3D model are tested in accurate 3D geological models to visualise and analyse the field. We present the workflow and preliminary results ore delineation in order to understand the controls on from a case study at the Navachab gold deposit (Namibia), mineralisation processes. Implicit modelling is capable where ore body geometries obtained from a 3D implicit of generating internally consistent and bias-free 3D model were linked to field observations. The results suggest geological models directly from drill-hole data; hence a strong structural control on mineralisation during the it can be used for objective structural interpretations. growth and lock-up stage of a regional scale dome. Implicit Instead of manual linkage of hand-digitised 2D cross- modelling combined with selective fieldwork allows us to sections, mathematical interpolation functions are used improve the understanding of structural controls on the to generate 3D isosurfaces, which can represent ore grade genesis of mineral deposits. Keywords: Email:

implicit modelling, structural control, folding, mineralisation, Navachab

stefan.vollgger@monash.edu

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference IVlonash University, 25 October 2012

Phase equilibria in sapphirine-bearing granulites C. J. WHELLER School of Earth Sciences, University of Melbourne, Porkvilie, Victoria, Australia

Ultrahigh-temperature metamorphism (UHT) lies at the Phase equilibria modelling in a quartz-saturated K20-Fe0extreme of metamorphic conditions and is achieved at Mg0-Al203-Si02-H20-Ti02-Fe203 (KFMASHTO) model temperatures exceeding 900 °C. The capacity for the system is undertaken using the software THERMOCALC lower crust to withstand such high temperatures is an in order to predict peak mineral assemblages which area of considerable interest for the understanding of the correspond to those stable in the Wilson Lake granulites. tectonothermal evolution of the lower crust. Diagnostic The resultant variety of calculated phase diagrams, of UHT metamorphism is the coexistence of sapphirine including P- T petrogenetic grids, P- T pseudosections, and + quartz (sa+q) in rocks. Calculated phase equilibria compatibility diagrams predict peak mineral assemblages modelling of these rocks provides an opportunity to corresponding to observed sa+q assemblages recorded explore the formation of UHT terranes. The new internally from high-grade terranes from around the world. The consistent dataset of phase end-members (Holland & new a-x model for sapphirine proposed in this study Powell, 2011), necessitates re-evaluation of the sapphirine allows for a pseudosection thermobarometry approach in activity-composition (a-x) model. This is achieved by NCKFMASHTO to provide a means of estimating peak P-T using sa+q bearing granulites from Wilson Lake, Canada conditions of sapphirine -h quartz bearing rocks in a range to calibrate end-member thermodynamics of sapphirine. of oxidation states. References An improved and extended internally-consistent thermodynamic dataset for phases of petrological interest, involving a new equation of state for solids. Journal ofMetamorphic Geology 29, 333-383.

HOLLAND, T. J. B., POWELL, R. 2 0 1 1 .

Keywords: Email:

THERMOCALC, sapphirine, UHT, phase equilibria modellir^g

c.wheller@student.uninnelb.edu.au

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Understanding the context of orogenic gold deposits in Archaean terranes: architecture & evolution of the stratigraphy north of the Waroonga Complex, Agnew, Yilgarn Craton, Western Australia A. J. WHITWORTH School of Geosciences, Monash University, Clayton, Victoria, Australia

Archaean-age terranes are found to host structurally and stratigraphy. These units are greater in thickness compared stratigraphically controlled gold deposits, however, gold to those deposited in proposed sub-basins further to the mineralisation processes are poorly understood. A 5 km south in the Redeemer-Waroonga corridor, suggesting long-section north of the Waroonga Complex at the Agnew deposition occurred within a larger basin. The southern Gold Mine, located within the Yilgarn Craton, was analysed half of the long section is the most deformed and altered, in terms of stratigraphy and structural architecture reflecting intense deformation by, and fluid infiltration to determine the relationships between the different along the Emu Shear, while units to the north, where the lithofacies, deformation and gold. This was achieved Emu Shear disappears and/or breaks into a series of splays, by graphic logging of diamond drill core, stratigraphic show only weak deformation and alteration. There is little correlations, major, minor and trace element geochemistry mineralisation within the area, which is in stark contrast and microprobe and petrographic analysis. Fourteen to that seen in the Redeemer-Waroonga corridor. The lithofacies representing six of the formations recognised paucity of gold is attributed to a reduction in deformational at Agnew were identified and consist of the lowermost structures and hence, a reduction in fluid conduit pathways Agnew Ultramafic komatiitic flows topped by pillow basalts within the study area, as well as greater unit thickness of the Redeemer Basalt, which are overlain by Mafic- retarding fluid flow. These results suggest smaller subUltramafic and Polymictic Volcanic Conglomerates and basins are more prospective for gold mineralisation than Edmunds Facies and Scotty Creek Formation Sandstones, larger basins and this knowledge can be applied to enhance which indicate an initial subaqueous and later sub-aerial gold exploration in Archaean terranes around the world. environment. Dolerite and felsic intrusions cut across the Keywords: Email:

Archaean, Agnew, gold, basin

anne.whitworth@nnonash.edu

Geological Society of Australia Abstracts 104

25th Victorian Ur^iversities Earth and Environmental Sciences Conference Monash University, 25 October 2012

Index of Primary Authors A Arnnit^R. J

Atkinson, A

Lipar,M

Loughran,T

Mare, E

McGloin, M

Beall, A. P

McRobert, A. D

Boyce, J

9, 10

Badlan, R

Noorda, J

Chen, Y

Chen,Z

P Perveen, R

D Dean, J

Delahunty, A. J

DeirErtole,D

Driscoll, J. R

Q Quinney, A R

E Edwards, M. J

EngwelLS. L

Redi, D.

Robson,T.

Saumur, B. M

Sharp, A

Felgate, M

Sinnnnons, J

Fiddes,S

Stanford, W.

Finch, M. A

G Goyen, S

Green, H. E

V Vollgger, S. A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

L Lai, E. C. 8

Uehara, D 24

I lies, K

Teske, J U

H Hunter, N.J

Tait,A.W.

Wheller,C. J. 26

Whitv\/orth, A. J.

....45 46

Geological Society of Australia Abstracts 104

25th Victorian Universities Earth and Environmental Sciences Conference Monash University, 25 October 2012

48 ,