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NSW

NSW Branch: Special Presentation by Ken Witherly and Annual Student Night

Wednesday, November 16, 2022
1730
1900

ASEG NSW November Meeting

Time and Date: 5:30 for 6pm start, Wednesday 16 th November 2022
Location: Club York, 99 York Street, Sydney

This year, our November technical meeting will consist of two parts:
Special Presentation: By Ken Witherly (Condor Consulting, Inc)
The Greatest Obstacle to Discovery Is Not Ignorance - It Is the Illusion of Knowledge.

Annual Student Night:

Recipients of the 2022 student scholarship will present their research:

Mackenzie Baker (UNSW) - Australia Going Under: Mantle processes and their geomorphological and biogeographical implications.
Eric Wang (USYD) - Seismic Hazard and Risk Modelling in Sydney.

Talk Overviews:

The Greatest Obstacle to Discovery Is Not Ignorance - It Is the Illusion of Knowledge

The title of this piece I term the Paradox of Discovery, has been attributed to Daniel J. Boorstin, Stephen Hawking, Henry Thomas Buckle, William H. Whyte, Anonymous and others. Like so many “quotes” available on the Internet, no one knows for sure who said it, why she or he said it, and what it really means, if it was said at all. My journey to ‘discovering’ this adage had me assembling a string of words that in a rough way, replicated the expression I found was a good encapsulation of what I was trying to express. After a relatively short time, the text as shown emerged. So for me, what does this expression convey? First, I was trying to find something which could capture how I feel about the 50 year career I have had in minerals exploration as a geophysicist. Specifically, could I convey what I feel has been the greatest obstacle to success; mostly typically the discovery of new mineral resources. To achieve this outcome, we typically rely on data which either we have caused to be gathered or is available due to the work of others. The data you generate is typically thought as being the ‘best guess’ of what is required to make the discovery for a certain deposit model which you have either accepted based on work of others or that you developed. The data you acquire is expensive compared with preexisting data and will often require time to decide what data is required, the definition and justification of budgets to pay for the work and then the impact of the time for planning, field preparation, acquisition and assessment, followed finally by the execution of a field program. Data acquired by others, while relatively inexpensive compared with ‘acquired for purpose’ data, is not likely carrying the critical information required to build a working hypothesis as to whether an unknown mineral deposit is located in the location you have deemed prospective. There is a commonly held belief in minerals exploration that when the same information is presented to different groups, the same outcome is most likely. So if previous explorers failed to locate a deposit using a given data set, other explorers are not likely to do any better. Collective industry experience suggests that the same data needs to be reviewed by five groups before a discovery is likely. This can be where the illusion of knowledge can first appear. This is a person’s or group’s belief that they possess some unique knowledge beyond the factual information available which will enable them to make better decisions that others with the same data. Can such data actually exist? Yes but its very nature can make our understanding and value of such data very difficult. Unless such knowledge is validated, the assessment process can be biased to the point that it is no longer a process whose outcomes are to be trusted. Moving past what might be called ‘dodgy data’, we can enter into the realm of ‘unknown unknown’ information. To pursue the discovery quest relying on such knowledge is inherently risky since the very nature or value of such information can be almost impossible to define.In the span of the 50 years I have pursued the discovery of new minerals deposits, the greatest gap in knowledge can only be termed ‘willful ignorance’ on the part of many of the fellow travelers in the exploration journey, those termed economic geologists who have not been able to appreciate the knowledge available to them which they chose to ignore or not take full advantage which geophysics can provide. Break this barrier down and the illusion of knowledge will be a manageable challenge and pursuing ‘unknown unknowns’ will be an enjoyable pastime.

 

Mackenzie Baker – Australia Going Under: Mantle processes and their geomorphological and biogeographical implications.

My project will assess the implications that tectonics, particularly dynamic uplift, intra-plate stress fields and palaeodrainage, has had on biogeography across the Australian continent. Australia has been chosen due to the intraplate setting that has made the continents tectonic activity relatively stable (Quigley et al., 2010; Sandiford, 2007). Throughout the history of Australian biogeography studies, climate has been frequently assumed as the main driver to biodiversification (Crisp et al., 2004). However, as we understand more about the connection between the mantle and the Earth’s surface, it becomes increasingly evident that alternative factors such as tectonics, must be considered in the biogeographical classification process (Ebach and Michaux, 2020). The previous narrative that climate acts as the main driver to bioregionalisation does not adequately explain the diversification of Australian species, river and drainage changes, nor does it fit into the climate schemes assumed by other continents that take on the equatorial climate approach (Ebach and Michaux, 2020). By studying the mantle and tectonic processes causing dynamic topography and other geomorphological changes, new constraints to the evolution of life on Earth can be gained. My project will examine the changes to the Australian landscape that have been brought about by tectonic and mantle processes since the Neogene (23.03Ma), including the continent-wide asymmetry of the Australian shorelines known as the ‘tilt’. As Australian traverses northward towards SE Asia, there are manifestations of geomorphological change that can be seen on the surface due to mantle processes. Previous studies of the Australian continent have determined a NNE down, SSW up, ‘tilt’ of the continent. The cause of this tilt has been determined to occur through mantle undulations causing dynamic topography. Due to this tilt, geomorphological changes have occurred on the surface, and can be seen through drainage changes, river reversals and sea level changes. As the continental surface is undergoing geomorphological change, the environments in which plant and animal species are situated upon are directly impacted by this and can be expected to alter the distributions of various species. Due to this, Australia provides an excellent canvas for studying the potential effects tectonics can have on the distributions of species across a given study area. The project will aim to determine this link through modelling the Australian continent from 40Ma to the present, using the PyBadlands software. By using PyBadlands, varying parameters of the Australian continent can be set and tested in order to reach conclusions about the relationship between tectonics and changes to the Australian landscape that may ultimately lead to changing of species distributions. 

 

Eric Wang (USYD) - Seismic Hazard and Risk Modelling in Sydney.

My Honours project is on seismic hazard and risk modelling for Sydney. Southeast Australia receives an alarmingly large number of low magnitude earthquakes. However, the 1989 Newcastle Earthquake and 2021 Mansfield Earthquake has shown that this area, and therefore Sydney, is vulnerable to moderate magnitude earthquakes, and increasingly so with growing population density. In 2018, Geoscience Australia created the National Seismic Hazard Assessment Map (NSHA18). It successfully integrates various datasets to allow for large-scale peak ground acceleration probability analysis, and it has found that Sydney is within a region of high seismicity (also known as the SE Seismic Zone). However, there are many variables for small-scale analysis it does not consider due to the enormity of the project such as elevation and seismic site conditions (i.e. soil/geological properties). Furthermore, it does not consider risk, the human vulnerability aspect, such as fatalities, economic loss, and infrastructure. As such, the aim of this project is to create local scale hazard models for Sydney, identify areas of high hazard, and create risk models (specifically targeted at infrastructure) for those areas. I aim to use OpenQuake by the Global Earthquake Model Foundation, an open-source software (python based) that has been used to create many national probabilistic seismic hazard maps such as in Italy, Canada, and Australia. In general, OpenQuake requires three input variables for their various hazard models: fault characteristics (fault location, dip, rake, etc.), ground motion models, and site conditions. Subsequent infrastructure data can be overlayed for risk analysis. All datasets are obtained from online sources such as government websites (e.g. Geoscience Australia) or journal articles. Below is a preliminary probabilistic seismic hazard analysis map for my thesis and it is the most common for determining seismic hazard of an area. It estimates the chance of sites to exceed a certain ground motion level (usually in peak ground acceleration). This is typically described by 10% probability of exceedance in a 50- year period or 1/475 annual exceedance probability. The figure shows two major areas of high hazard in Sydney: the Botany Bay area (east) and Yarramundi area (west). Botany Bay is an area of concern due to its high population density while Yarramundi is relatively less concerning as it is sparsely populated. Therefore, future risk models will be focused on Botany Bay, followed by Yarramundi if time permits.

Is there a seismic refraction signature for sulphide mineralisation?

Wednesday, October 19, 2022
1800
1900

On Tuesday 19th October, 6:00pm AEDT, ASEG NSW is bringing you a talk by Derecke Palmer (UNSW) titled Is there a seismic refraction signature for sulphide mineralisation?

Although I accepted retirement from UNSW almost two decades ago, I have continued with my longstanding research interests in near surface refraction seismology. The major theme of my research has been full trace processing. Inexorably, full trace processing leads into detailed model building with traveltimes and amplitudes. My presentation addresses three important questions.

The first is “Is there a seismic refraction signature for sulphide mineralisation at the base of the regolith?” The second is: “Will full waveform elastic inversion rapidly replace traveltime acoustic tomographic inversion, and become routine with most geotechnical investigations?” The third is: “Would a detailed analysis of the refraction component of selected regional reflection profiles recorded by GA be useful?” The presentation employs seismic data recorded by GA near a major operational gold mine.

Attendance is by joint Zoom virtual + physical presentation at Geoscience Australia.

Register Here: https://us02web.zoom.us/webinar/register/WN_vdsnFZAuRp2egjpFX1QLbQ

Please bring your own drinks and nibbles if attending online.

ASEG NSW - talk by Berta Vilacís

Wednesday, September 21, 2022
1800
1900

Topic: ASEG NSW - talk by Berta Vilacís

Presenter: Berta Vilacís

Date and time: Sep 21, 2022 06:00 PM

Registration: https://us02web.zoom.us/webinar/register/WN_p_jGJ9-ESQaR2j_c9XroWQ

 

Overview:

Mantle convection is an essential driving force of plate tectonics. It affects the horizontal and vertical motion of the Earth’s surface. The horizontal motion of the lithosphere is observed in the spreading rates, while its vertical motion leaves an imprint the geological record. In particular, positive surface deflections driven by mantle convection create erosional/non-depositional environments, which induce gaps in the stratigraphic record (i.e., hiatus). Modern digital geological maps allow us to map no-/hiatus surfaces at continental scale systematically and use them as a proxy for mantle flow induced dynamic topography. We find that hiatus surfaces change in timescales of geological series. This is consistent with the presence of a weak upper mantle. Also, we find significant differences in the spatial scale of inter-regional hiatus, on the order of 2000-3000 km in diameter, which can be linked by fluid dynamic analysis to active upper mantle flow regions. Our results highlight the importance of geological datasets to further understand geodynamic processes in the deep Earth. Also, they indicate that studies of horizontal and vertical motion of the lithosphere to track past mantle flow would provide powerful constraints for adjoint based geodynamic inverse models of past mantle convection.

Bio:

Berta Vilacís is a PhD student in geodynamics at the Ludwig-Maximillians-Universität München (LMU Munich). She did her bachelor in Physics in the University of Barcelona focusing in applied seismology during her final year. At the same time she got a one-year fellowship in the Catalonia seismic network. After working in maintaining and processing data from the IEC seismic network in 2017, she moved to Munich where she got her MSc in Geophysics by TUM and LMU Munich. In 2019, she started her PhD in Hans-Peter Bunge’s group. Her research focuses in using geological information, such as geological maps, as a way to observe, map and track past mantle convection.

 

NSW Branch - joint SMEDG – ASEG: A completely different geophysical way to explore for sulphides. Heterodyne method - latest progress and field results

Thursday, July 28, 2022
1730
1900

Joint SMEDG – ASEG night on the 28th July @ 1730. 

More detail to follow. 

Title: A completely different geophysical way to explore for sulphides. Heterodyne method - latest progress and field results

Presenter: Steve Collins

Registration to virtual component: https://us02web.zoom.us/webinar/register/WN_aLKzFUIwRt2-b_UgzSVwOA

 

A completely different geophysical way to explore for sulphides.

Heterodyne method - latest progress and field results.

 

Steve Collins (presenter), Bob White, Keith Leslie, Andrew Sloot

 

Abstract

How many ore deposits lie at relatively shallow depths but are invisible to geophysical methods, because they are submerged in graphitic black shales? How many thousand strike kilometres of graphitic black shale are prospective for base metal sulphide deposits? The heterodyne method addresses the problem of distinguishing sulphides from graphite.

 

As a retirement 'project' (aka hobby) our intrepid team of wrinkly geophysicists has been researching the possibility of using the semi-conducting properties of sulphide minerals to develop an electrical method of detecting subsurface sulphide deposits which does not respond to graphitic black shale. In the future, the method also has the potential for detecting poorly conducting lead zinc mineralisation such as Mississippi Valley style or Broken Hill which may otherwise be invisible.

 

This project, largely funded and supported by Fender Geophysics, follows up on work done by Bob White nearly half a century ago. The field operation of the method, superficially, looks like Induced Polarisation but is based on an entirely different physical property. If it can be shown to work, it is envisaged that field surveys using this technique will be incorporated into IP surveys as most of the logistics involved is identical. The method may also be amenable to airborne implementation since laboratory tests indicate that the frequencies at which it can operate extend into the range usually used in electromagnetic surveying.

 

Several field surveys have been run at Argent Minerals' Kempfield deposit and the latest of these strongly suggests that method works, - responding to sulphides but not to black shales. This work needs final verification but the authors of this talk feel that the Holy Grail is now within grasping distance.

 

The talk covers the history of development, and (in words of one syllable, where possible) the theory behind the method. The latest field results will be discussed together with plans for future work and further development.

 

Biographies

Steve Collins has a BSc in physics and an MSc in geophysics from Macquarie University. He has over 40 years experience as a mineral exploration geophysicist for multi-nationals and as a consultant. He has been a member of ASEG for 45 years and was on the organising committee of SMEDG for nearly two decades. He is an honourary life member of SMEDG and has been awarded the Lindsay Ingall award by the ASEG.

Bob White has an MSc degree in geology and geophysics from Macquarie University. He has more than 40 years experience as a practical mineral exploration geophysicist both as a company employee and as a consultant.

Keith Leslie currently multi tasks between his roles of CSIRO mentor, grandfather, dinghy sailor and collecting and analysing data for the non-linear sulphide project. He is also working at CSIRO with Clive Foss on characterising magnetic signatures of meteorites and some local objet d'art.

Andrew Sloot is a graduate of Macquarie University and is the owner of Fender Geophysics, a Sydney base geophysical contracting company. Fender is the engine under the bonnet of this project and provides financial, logistics and moral support. Andrew has been on the SMEDG committee since 2010 and also holds the ASEG Lindsay Ingall award.

 

3D geological modelling: a multi-source heterogeneous data integration tool to advance the knowledge of geological regions, mineral systems and groundwater resources. An example from NSW.

Wednesday, June 15, 2022
1800
1900

Title: 3D geological modelling: a multi-source heterogeneous data integration tool to advance the knowledge of geological regions, mineral systems and groundwater resources. An example from NSW.

Presenter: Dr. Giovanni Spampinato

Date: 15 June, 2022

Time: 1800-1900

Registration: https://us02web.zoom.us/webinar/register/WN_qIybq1hzRq612TLzwTX-XQ

Overview:

The geological architecture and associated mineral resources in eastern Australia are largely obscured by post-Carboniferous sedimentary and volcanic cover. This poses serious challenges towards the understanding of the tectonic evolution of Phanerozoic Australia as well as the ability to find new resources undercover.

Over the past decade, 3D geological modelling has become a fundamental tool to better understand the architecture and unravel the mineral potential of buried terranes.

Recently, the Geological Survey of NSW has developed a series of interlocking 3D models of orogenic provinces, basins, major faults and thickness of post-Carboniferous cover across the state. Constraining datasets for the construction of the 3D models include surface geological mapping, geological cross-sections, well data, digital elevation models, seismic, gravity and magnetic data and 2D forward models. These synthetic 3D models consolidated the available geological datasets and refined the existing interpretations. The NSW 3D Models also establish a fundamental state-wide geological framework that will provide context for future 3D models and geological surveys.

3D modelling is now within everyone's reach. The fact that prospective rocks lie, for the most part, untested beneath cover creates a tremendous opportunity for better prediction and exploration strategies using the latest advances and technologies. The rapid development 3D geological modelling tools as well as increased computing power allow geologists to take a more robust, holistic scientific approach to geological investigation, mining exploration, project design and quantitative resource estimation.

 

Bio:

iovanni is an experienced geophysicist with project management background. His expertise includes processing and interpretation of geological and geophysical data, 3D modelling & inversion and large data management for mineral exploration, resource evaluation and targeting.

Giovanni completed a PhD at Monash University that contributed to a better understanding of plate architecture and evolution of the transition between Proterozoic Australia and the eastern margin of Gondwana, with a focus on the southern Mount Isa terrane and the central Thomson Orogen in Queensland.

Before joining CSIRO, Giovanni worked as a senior geoscientist and 3D modeler at the Geological Survey of NSW, building 2D and 3D geological and structural models of tectonic provinces, basins and sites of interest, and working with geologists to ground truth them in order to improve/update geological interpretations. He has worked at a range of scales, modelling shallow features in regolith, as well as deep crustal-scale features. His current role at CSIRO will contribute to create new knowledge and methods in the field of 3D geological modelling through an integrated approach, developing new technologies to mitigate 3D geological risk in resources management and support industry programs for Exploration Through Cover and Orebody Knowledge

NExUS - Geological Interpretation of Aeromagnetic Data – a Practical Approach

Tuesday, August 2, 2022
TBC
TBC

Geological Interpretation of Aeromagnetic Data – a Practical Approach

2-Day Online Workshop, 1st – 2nd August 2022

(Limited to 30 places)

 

NExUS-Professional Development (NExUS-PD) is proud to be able to present this very highly regarded workshop online for the very first time.
• The specially designed two-day online workshop* will introduce the fundamentals of geological interpretation of aeromagnetic data.
• The workshop will feature lectures, practical activities and case studies all using integrated data sets.
• Each day will feature 3 x 2hr sessions with exercises to be completed between the sessions and time allocated for extended discussions.
• The format aims for open, transparent communication, with input from participants highly encouraged to share knowledge and experiences.
*This is a level-4 course (honours level) and is designed to be suitable for early career geoscientists, honours students and HDR students. The workshop is not assessed.

 

Day 1, Methodology of Aeromagnetic Interpretation – David Isles (1st Aug) :
• Sessions will include: Basic Principles, Physics and Concepts of Magnetics, Spatial Concepts, Survey Planning, Processing and Presentation of Data, Anomalies, RTP and Analytical Signal, Modelling and Inversion, Introduction to Golden Dyke Prospect Case Study
Day 2, Geological Interpretation and Structure – Leigh Rankin (2nd Aug) :
• Sessions will include: Golden Dyke Prospect Case Study, Magnetisation in Rocks, Charters Towers Case Study, Structures in Magnetics, Widgiemooltha Case Study, Unusual Magnetisation and Final Q+A session.

To Register, click here. 

Full Registration: $500

AIG and ASEG Members: $400

Students: $50

For further information view this flyer or, please contact: Richard.Lilly@Adelaide.edu.au

NExUS - Geological Interpretation of Aeromagnetic Data – a Practical Approach

Monday, August 1, 2022
TBC
TBC

Geological Interpretation of Aeromagnetic Data – a Practical Approach

2-Day Online Workshop, 1st – 2nd August 2022

(Limited to 30 places)

 

NExUS-Professional Development (NExUS-PD) is proud to be able to present this very highly regarded workshop online for the very first time.
• The specially designed two-day online workshop* will introduce the fundamentals of geological interpretation of aeromagnetic data.
• The workshop will feature lectures, practical activities and case studies all using integrated data sets.
• Each day will feature 3 x 2hr sessions with exercises to be completed between the sessions and time allocated for extended discussions.
• The format aims for open, transparent communication, with input from participants highly encouraged to share knowledge and experiences.
*This is a level-4 course (honours level) and is designed to be suitable for early career geoscientists, honours students and HDR students. The workshop is not assessed.

 

Day 1, Methodology of Aeromagnetic Interpretation – David Isles (1st Aug) :
• Sessions will include: Basic Principles, Physics and Concepts of Magnetics, Spatial Concepts, Survey Planning, Processing and Presentation of Data, Anomalies, RTP and Analytical Signal, Modelling and Inversion, Introduction to Golden Dyke Prospect Case Study
Day 2, Geological Interpretation and Structure – Leigh Rankin (2nd Aug) :
• Sessions will include: Golden Dyke Prospect Case Study, Magnetisation in Rocks, Charters Towers Case Study, Structures in Magnetics, Widgiemooltha Case Study, Unusual Magnetisation and Final Q+A session.

To Register, click here. 

Full Registration: $500

AIG and ASEG Members: $400

Students: $50

For further information view this flyer or, please contact: Richard.Lilly@Adelaide.edu.au

NSW Tech Night - The use of machine learning in processing remote sensing data for mineral exploration

Wednesday, April 20, 2022
1800
1900

Title: The use of machine learning in processing remote sensing data for mineral exploration

Presenter: Dr. Ehsan Farahbakhsh

Date: Wednesday 20th April 2022

Time: 1800-1900

Registration: https://us02web.zoom.us/webinar/register/WN_2iHaItV9Sk201SP4ZFkPpw

Overview:

The decline of the number of newly discovered mineral deposits and increase in demand for critical minerals in recent years has led exploration geologists to look for more efficient and innovative methods for processing different data types at each stage of mineral exploration. As a primary step, various features, such as lithological units, alteration types, structures, and indicator minerals, are mapped to aid decision-making in targeting ore deposits. Different types of remote sensing datasets, such as satellite and airborne data, make it possible to overcome common problems associated with mapping geological features. The rapid increase in the volume of remote sensing data obtained from different platforms has encouraged scientists to develop advanced, innovative, and robust data processing methodologies. Machine learning methods can help process a wide range of remote sensing datasets and determine the relationship between components such as the reflectance continuum and features of interest. These methods are robust in processing spectral and ground truth measurements against noise and uncertainties. In this presentation, I will provide a brief introduction to remote sensing data types and review the implementation and adaptation of some popular and recently established machine learning methods for processing different types of remote sensing data aiming at detecting various ore deposit types. I will also review our recent studies on combining remote sensing data and machine learning methods for mapping different geological features that are critical for providing mineral potential maps.

Bio:

Dr. Ehsan Farahbakhsh is a Research Associate in the EarthByte Group, School of Geosciences, University of Sydney. He holds a PhD degree in Mining Engineering - Mineral Exploration from Tehran Polytechnic. He has been involved in several projects as an exploration geologist or spatial data analyst for the exploration industry, primarily for providing prospectivity maps of various ore deposit types from regional to deposit scale. His research interests are multidimensional mineral prospectivity modeling, geological remote sensing, geostatistics, and the application of data science and UAVs in mineral exploration.

Surface wave tomography in engineering: Move over MASW, FTAN is here.

Wednesday, March 16, 2022
1800 (AEDT)
1900 (AEDT)

Title: Surface wave tomography in engineering: Move over MASW, FTAN is here.

Presenter: Dr Craig O’Neil

Date: Wednesday 16th March 2022

Time: 6:00 pm to 7:00 pm AEDT

Registration: https://us02web.zoom.us/webinar/register/WN_cAHHIn2YQDe9VOWKmH-T6Q

 

Abstract:

Many large scale civil works, such as dams and foundations, require a detailed knowledge of the shear-wave velocity and elastic properties of the underlying bedrock. These properties determine the earthquake risk and ground acceleration of a dam, or the vibrational response of built structures. Over recent years, multichannel analysis of seismic waves (MASW) has been widely adopted to provide this information, and has been incorporated into engineering guidelines such as ANCOLD.  However, these methods are time intensive, and a high level of interpreter skill is needed to identify phase velocity modes within noisy data, and misinterpretation of fundamental modes can lead to unrealistic geological models.  Here we develop an approach from the research seismology realm - frequency time analysis (FTAN) - to provide an alternative approach. Field acquisition can co-opt existing refraction surveys, and uses a Gaussian-band filtering to identify fundamental and higher group velocity modes in the data, which can be inverted for vertical S-wave velocity structure. I show a number of field examples, and highlight the approache's ability to discern site-specific engineering information such as rock-mass classification, degree of weathering, and earthquake risk to structures. An explosion of development in renewable infrastructure, from wind onshore and offshore wind turbines and foundation characterisation, pumped hydroelectricity schemes, and geothermal reservoir development, is being seen recently, and the FTAN approach offers a reliable and affordable way of characterising local geotechnical properties

Bio:

Dr Craig O’Neill has over 17 years’ experience in geophysics, engineering geology, and computational geoscience. He has utilised geophysical techniques and geological approaches to deliver on diverse projects from groundwater exploration in remote communities, archaeological excavations in Italy, electromagnetics for copper mineralisation, and geothermal characterisation of deep sedimentary basins. He has supervised projects in slope stability and landslide risk in developing countries, drone photogrammetry, and rock mechanics. He developed a geotechnical laboratory and teaching program at Macquarie University, where he was also director of a major Research Centre. He also has a long experience with computational geoscience and machine learning. He has over 74 highly cited Earth Science papers, and was a member of the Australian Academy of Science’s National Committee for Earth Science, where he helped draft the National Decadal Plan

NSW tech night: Geophysical vectors for iron oxide copper-gold (IOCG) exploration: Cloncurry METAL project.

Wednesday, February 16, 2022
1800 AEDT
1900 AEDT

Title: Geophysical vectors for iron oxide copper-gold (IOCG) exploration: Cloncurry METAL project.

Presenter: Dr James Austin (CSIRO)

Date & Time: Wednesday 16th February 2022 at 1800

Registration: https://us02web.zoom.us/webinar/register/WN_bLEg37-vT_Gnf2Zm8Dw_Lg

Abstract:

The classic Status Quo of IOCG exploration is “the combined gravity-magnetic high”. Whilst historically successful for IOCG exploration, it is not useful for many Cloncurry “IOCGs”, which may be magnetite-, to hematite- or pyrrhotite-dominated or have negligible dense or magnetic minerals. Many Cloncurry IOCG’s don’t have significant gravity anomalies, some do not have significant magnetic anomalies, and some neither. IOCGs do however have predictable geophysical zonation related to alteration zonation. They tend to form on redox and/or pH gradients and they are structurally controlled. This talk will outline three novel geophysics-based approaches to IOCG exploration. It will explore how metasomatic processes can be translated into geophysical parameters, propose methods to map redox gradients/structures using integrated geophysics and petrophysics and illustrate how anisotropy of magnetic susceptibility (AMS) data integrated with quantitative mineralogy can objectively map structural controls and predict ore body geometries.

Bio:

Jim studied structural geology and applied geophysics at Macquarie University, in the halcyon days, late last millennia. He gained employment as a cartographer and illustrator on the Australian Geographic Magazine in 1999 and commenced a PhD on the Cloncurry Lineament in 2003. Post PhD Jim worked in mineral exploration, geophysics consulting, and hydrocarbon exploration across Australia. Since joining CSIRO in 2011 Jim’s main passion has been integrating petrophysics with mineralogy, structural geology, and geophysics to better understand the inner workings of mineral deposits. Jim was part of the organising committee for the inaugural AEGC conference in 2018, sat on the ASEG Fedex in 2019, and was president of the NSW branch of the ASEG up until a few moments ago.

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