Geoscience Society/AGC – Webinar: Iron-Oxide Copper-Gold (IOCG) Deposits: Definition, Nature, Tectonic Setting and Magmatic-Hydrothermal Origin

Participants will gain an insight into the iron oxide-copper-gold (IOCG) group of deposits, discussing the temporal distribution and tectonic environments of the various subtypes.

Date: Tuesday 11th August 2020

Time: 5.00 pm – 6.00 pm AWST

Presenter: Professor David I Groves – Recipient of AGC’s National Geoscience Champion Award in 2018

Cost:

AusIMM Member – Free

Member of an AGC Member Society (AIG, GSA, ASEG etc.) – Free

Non Member – $20.00

To register, go to this link

Digital Tech Talk Overview

This talk has a closer look at iron oxide-copper-gold (IOCG) group of deposits, discussing the temporal distribution and tectonic environments of the various subtypes. The sub-classes include low-Ti iron oxide-associated deposits that include iron oxide (P), iron oxide (F, REE), skarn Fe or Cu-Au and high-grade Au ± Cu.

It appears most likely that formation and preservation of giant IOCG deposits was largely a Precambrian phenomenon related to heightened activity of mantle plumes that impacted on buoyant  metasomatized SCLM at that stage in Earth history, with Phanerozoic IOCG deposits forming only rarely in tectonic settings where conditions similar to those in the Precambrian were replicated.

Presenter Bio

David Groves was born in Brighton, England, and migrated to Tasmania where he was educated at Hobart High School and at the University of Tasmania, completing a PhD on the giant Mt Bischoff tin deposit under the mentorship of Mike Solomon. After a period with the Geological Survey of Tasmania, where he learned mapping and field skills, David was appointed Lecturer in Economic Geology at the University of Western Australia (UWA) in 1972. In 1987, he was awarded a Personal Chair at UWA and formed the Centre for Strategic Mineral Deposits, which morphed into the Centre for Global Metallogeny, with him as Director, and which became the Centre for Exploration Targeting after his retirement as Emeritus Professor. He had a very successful academic career in terms of approximately 500 highly-cited published papers and book chapters, many keynote and invited lectures, and mentorship of many outstanding postgraduates, being awarded 12 medals and prizes, including the SEG Silver and Penrose Gold Medals and the SGA-Newmont Gold Medal, and being inducted into the Australian Academy of Sciences as a Fellow. He has been President of GSA, SEG and SGA during his career and represented Australia on UNESCO committees.

https://events.csiro.au/Events/2020/July/10/Our-Knowledge-Our-Way-Launch?

Online virtual event

To join us, please register by clicking ‘Register now’ below. You will receive a confirmation email with further information.

Indigenous-led approaches to strengthening and sharing our knowledge for land and sea management, Best Practice Guidelines from Australian experiences.

About the event

The launch will feature a short film, followed by a Q&A session with Indigenous co-authors and partners.

With contributions from over 100 Indigenous individuals and organisations, these Indigenous-led Guidelines support a step-change in learning, by both Indigenous peoples and their partners, about best practice ways of working with Indigenous knowledge to look after land and sea Country.

Supported by NAILSMA and CSIRO, the Our Knowledge Our Way Guidelines are based on 23 case studies that illustrate the critical principle that Indigenous people must decide what is best practice when working with their knowledge.

Join us for our Online virtual event

Please click Register Now
to join us

Webinar details:

Wednesday August 12th is available for a live webinar. 

12.30 - 2.30pm AEST (10.30am - 12.30pm AST)  

Registration at the following link. https://tas.currinda.com/register/event/2134

Imposter Syndrome/ Inner critic workshop

Have you felt like a ‘fake’ and some point in your career? Have you questioned why people should listen to you when presenting? Have you worried you may be ‘found out’? Or, has a nagging voice in your head told you that it was ‘luck’ which awarded you the position you are in now? Well, you’re not alone. Up to 70% of people are likely to experience ‘impostor’ like symptoms in some capacity in our careers. In this practical and interactive session, learn the four critical elements to working with your Inner Critic, identify how to work collaboratively with limiting beliefs which may also limit your success; and learn practical tactics you can implement to influence your next steps.

Title: End-to-end seismic inversion of geostatistically complex reservoir facies models with deep convolutional neural networks

Anshuman Pradhan, Stanford University

Date & Time: 6th August 2020; 12 – 1PM AWST

https://us02web.zoom.us/webinar/register/WN_-3DqbXyKRuuQL88cngGFBg

Summary:

We present a framework for performing end-to-end seismic inversion of reservoir facies models under complex geostatistical models of prior uncertainty. In our methodology, we directly learn the end-to-end inverse mapping between 3D seismic data and reservoir facies using deep 3D convolutional neural networks. Our training dataset is simulated from the forward generative model comprising of the geostatistical prior on facies and geophysical model relating seismic to facies through elastic properties. To ensure reliability during prediction with real data, a method for performing data-based falsification of prior uncertainty is presented. Using a real case study from an offshore deltaic reservoir, we demonstrate the efficacy of our approach by inverting a large-scale facies model from 3D post and partial stack seismic data.

Biography:

Anshuman Pradhan is a PhD candidate in the department of Energy Resources Engineering at Stanford University. He is a research assistant associated with the Stanford Center for Earth Resources Forecasting, Stanford Rock Physics and Borehole Geophysics project and the Stanford Basin and Petroleum System Modeling consortia. Anshuman obtained his M.S. and B.S. degrees in Applied Geophysics from Indian Institute of Technology (Indian School of Mines), Dhanbad, India. Anshuman has several industry and academic internship experiences where he has worked on applications related to reservoir modeling, seismic inversion and machine learning. 

Presenter: Alberto Ardid Segura

Date: 18th August 2020

Time: 1300 AEST

Title: Lithologically-constrained stochastic magnetotelluric inversion for imaging shallow conductors in geothermal fields

Abstract:

Geothermal fields are usually explored by magnetotelluric (MT) surveys primarily to characterize a shallow conductor reflective of a conductive clay structure, commonly known as the clay cap. Standard deterministic MT inversions suffer from non-uniqueness and uncertainty, and the inclusion of useful lithological information is still limited. We develop a Bayesian 1D inversion method that integrates the electrical resistivity distribution from MT surveys with Methylene Blue (MeB) data, an indicator of conductive clay distribution in geothermal wells. The inversion seeks to infer under uncertainty the shallow conductor boundaries in geothermal fields. By incorporating borehole information, our inversion reduces non-uniqueness and then explicitly represents the irreducible uncertainty as estimated depth intervals for clay cap boundaries. This is particularly important when constraining the lower conductor boundary, as this feature is difficult to discriminate from the MT alone.

We apply the methodology to a set of 250 MT stations and 130 MeB profiles in the New Zealand Wāirakei geothermal field to estimate under uncertainty the conductor boundaries. Then, we compare the infer boundaries with the clay distribution, temperature logs and lithology from wells to estimate temperature gradients and conductive heat flux through the clay cap. By quantitative correlations among the different data sets, we present an unprecedented view into clay capping structures in high-temperature liquid dominated geothermal fields.

Bio:

Alberto is a MSc geophysicist who studied at the University of Chile, and is a current Doctoral candidate at the Geothermal Institute in the University of Auckland. His doctoral research is focussed on studying the electrical resistivity distribution in geothermal fields through Bayesian magnetotelluric inversions that allows assimilating data from different properties such as lithology and temperature, and quantifying uncertainty. Prior to that, Alberto’s research focused on shallow active and passive seismic exploration on geothermal systems. He also has industry experience mostly related to R+D in direct current, gravity and magnetic geophysical methods for mining and basin research.

To register, please go to this link: https://us02web.zoom.us/webinar/register/WN_qDrzV7GsQOKBtCnBApxeBQ

Title: Contemporary crustal stress pattern of Australia

Summary:

The present-day stress field of Australia has been the subject of great interest in the three past decades because it shows a variable pattern for the orientation of maximum horizontal stress (S_Hmax) that is not parallel to absolute plate motion. Analysis of in-situ stress data across Australia (in >20 sedimentary basins) reveals four major trends for the orientation of S_Hmax including NE-SW in northern, northwestern and northeastern Australia, E-W in southern half of Western Australia and South Australia, ENE-WSW in most parts of eastern Australia and NW-SE in southeastern Australia. In addition, the results reveal significant rotation of stress within various sedimentary basins due to the presence of different geological structures, including basement structures, faults, fractures and lithological contrasts. Understanding and predicting local stress perturbations has major implications for determining the most productive fractures in petroleum and geothermal systems, and for modelling the propagation direction and vertical height growth of induced hydraulic fractures in unconventional reservoirs.

Biography of the presenter:

Dr Mojtaba Rajabi is an ARC DECRA Fellow at the School of Earth and Environmental Sciences, University of Queensland. He has over 12 years of extensive experience in crustal stress analysis, reservoir geomechanics, geomechanical-numerical modelling and petrophysics. He graduated with a Ph.D. in Earth Sciences from the University of Adelaide in 2017. Dr Rajabi has worked on the geomechanical analyses of >30 sedimentary basins from across the world including Australia, New Zealand, Middle East, Mozambique, Iceland and Western Mediterranean. Since 2012, Dr Rajabi has worked on the Australian and World Stress Map projects. He has received >15 international awards and prizes for his research including the ARC-DECRA Award, the Australian SEG Early Achievement Award, EAGE Louis Cagniard Award, and the International Lithosphere Program’s Flinn-Hart Award.

The ASEG welcome you to join us on ZOOM on Tuesday 7 July, 4pm (AEST) for a talk by David Annetts from CSIRO.

Ten years in the wild (Redux)

An updated and expanded version of the AEGC presentation providing background to a CSIRO project that was placed in the public domain in 2009.  The talk offers lessons and guidance for others who would walk a similar path.

The use of open-source codes has become pervasive over the past 20 years but such codes are uncommon in minerals exploration. The P223 series of programs researching forward and inverse modelling of electromagnetic data was supported by CSIRO and six AMIRA consortia over 27 years and produced, amongst others, the codes, Airbeo, LeroiAir and Marco. This project concluded in 2008 and, after a two-year embargo, the code base, consisting of computer programs modelling different approximations of the earth for ground and airborne prospecting systems, was released to the public. We discuss reasons why codes have not been more widely adopted, and examine the evolution of some of the codes in research, academia and in industry as a guide to parties who would embark on a similar route.

David Annetts has been with CSIRO since 2007. A forward-modeller by inclination, he has researched the application of frequency and time-domain electromagnetic prospecting methods to marine CSEM, CO2 sequestration, uranium and groundwater exploration, and maintains an active interest in CSIRO’s Bayesian Lithological Inversion initiative.  He is also the current ASEG President.

Register Now: https://us02web.zoom.us/webinar/register/WN_wRoI_iXERlmmAA-wtXjHLw

After registering, you will receive a confirmation email containing information about joining the webinar.

Please join us on Tuesday 14^th July,  5pm (AEST) for a talk by Marina Costelloe from Geoscience Australia hosted by FedEx.

Mentoring through change, a perspective

Building on her experience as an ASEG President, STEM ambassador, and senior manager with Geoscience Australia, this talk is aimed at geophysicists at any stage in their career and will cover our shared leadership challenges, what we need to do more of, and less of, where to go to for help and how you can make the most of new opportunities for your workplace, your teams and for you in your own leadership sphere. There will be lots of time for questions and discussions.

Biography:

Marina Costelloe is the Director of the Onshore Seismic and Magnetotelluric Section within the Mineral Systems Branch at Geoscience Australia. Marina has worked in areas as diverse as mineral exploration, groundwater, critical infrastructure, earthquakes, and data science and contributed to international nuclear monitoring and space weather over the past 25 years. In 2018, Marina took on the role of President of the Australian Society of Exploration Geophysics (ASEG). Marina represents the Geology and Geography Cluster on the board of Science and Technology Australia and represents Australia on the Society of Exploration Geophysics Pacific Regional Affairs Committee.

Register Now: https://us02web.zoom.us/webinar/register/WN_quT25XVVTLGxJNTyy3XE_Q

After registering, you will receive a confirmation email containing information about joining the webinar. Contact secretary@aseg.org.au if you have any questions.  

Please bring your own drinks and nibbles.

Please join us on Wednesday 17^th June,  6pm (AEST) for a talk by Claire Mallard from USYD.

Coupling Surface Evolution and Mantle Dynamics: two examples of the interplay of Tectonics, Eustasy and Surface Processes

Over deep time, mantle flow-induced dynamic topography as well as plate tectonic evolution drive deposition moderated by higher-frequency fluctuations in climate and sea level. The effects of deep mantle convection and lithospheric deformation impact all the segment of the source to sink systems at different wavelengths and over various scales which remains poorly quantified. Field observations and numerical investigations suggest that the long-term stratigraphic record along continental margins contains essential clues on the interactions between dynamic topography and surface processes. However, it remains challenging to isolate the fingerprints of dynamic topography, lithospheric deformation, eustatic variation and climate change in the geological record.

In the first part of the talk, I will show you how we use a new numerical simulation package that couples the open-source surface evolution code Badlands (https://badlands.readthedocs.io/en/latest/) with lithospheric-scale thermo-mechanical models (https://uwgeodynamics.readthedocs.io/en/latest/) for unravelling the effect of rift obliquity on the distribution of facies and the evolution of stratigraphic architecture in syn-rift deposits.

The second part will focus on the integration of mantle convection simulation results into Badlands to quantify the impact of different timings and wavelengths of dynamic topography migration on the surface. I will present an example of the last 40 Ma evolution of the South African landscape.

The results suggest that our source-to-sink numerical workflow can be used to explore, in a systematic way, the interplay between dynamic topography and surface processes and can provide insights into recognizing the geomorphic and stratigraphic signals of dynamic topography in the geological record.

Register Now: https://us02web.zoom.us/webinar/register/WN_lf3ScLqiRCyGYll3gLcUnA

After registering, you will receive a confirmation email containing information about joining the webinar. Contact secretary@aseg.org.au if you have any questions.  

Please bring your own drinks and nibbles.

Date: Wednesday 15 July

Presenter: Indrajit G. Roy (PhD)

A link to the Zoom webinar will be shared closer to the event date.

Title: Computations methods in Geophysics

Abstract:

Mathematical derivatives, since their birth within calculus in the last quarter of seventeenth century, have been occupying a most important place in almost every sphere of science.  They are fundamental to geophysical modelling and particularly potential field data analysis, from data presentation through to quantitative interpretation. But the challenges of robust and precise estimation of derivatives along with their implementation are many. This presentation will review some of those challenges, how to minimize errors and provide insight into many of their applications.