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On the cusp of a tear: continental subduction in the Banda arc

Tuesday, August 25, 2020
1430 (AEST)
1530 (AEST)

A new ASEG webinar brought to you by FedEx on Tuesday 25 August, 2:30pm (AEST) for a talk by Meghan Miller.

On the cusp of a tear:  continental subduction in the Banda arc

Eastward along the Sunda-Banda arc, convergence transitions from subduction of oceanic lithosphere to arc-continent collision. This region of eastern Indonesia and Timor-Leste provides an opportunity for unraveling the processes that occur during collision between a continent and a volcanic arc, and can be viewed as the temporal transition of the process of continental collision along strike.  We have collected a range of geological, geodetic, seismic, and geomorphic data to place constraints on the geometry and history of subduction. Utilizing ~4 years of new broadband seismic data we image the structure of the crust through to the mantle. Ambient noise tomography of the crust shows velocity anomalies along strike and across the arc, related to structure of the incoming Australian plate. The pattern of anomalies at depth resemble the system of salients and embayments that are present offshore western Australia, which formed during rifting of east Gondwana. At mantle depths, transition from oceanic subduction to continental collision appears reflected in new teleseismic based images, coinciding with previously identified changes in the geochemistry of the arc volcanics. Results from our body wave tomography show continuity of the subducting slab to depths of at least 300 km, with no evidence for tearing at the scale of >~50 km even in the region of arc-continent collision. Our expanded catalogue of Benioff zone seismicity reveals earthquakes in what was previously thought to be a seismic gap (the Wetar gap). Together, our seismic results suggest that tearing is not as advanced in this region as previously hypothesized, implying sustained subduction of continental lithosphere underneath the Banda arc. We suggest the tectonic evolution of this region is defined by inherited structure of the Gondwana rifted continental margin of the incoming plate.  Altogether, we suggest that this region is characterized by subduction of continental lithosphere poised for tearing that has perhaps just initiated, but with no large slab windows. Therefore, the initial template of plate structure controls orogenesis and deep mantle structure.

Register now: https://us02web.zoom.us/webinar/register/WN_MQI0S4DfQnyKG1hzAzoVYA

AusLAMP in the Tasmanides: Lithospheric architecture and mineral potential from magnetotellurics

Wednesday, September 9, 2020
1500 (AEST)
1600 (AEST)

A new ASEG webinar brought to you by FedEx on Wednesday 9 September, 3pm (AEST) for a talk by Dr Alison Kirkby, Geoscience Australia.

AusLAMP in the Tasmanides: Lithospheric architecture and mineral potential from magnetotellurics

This presentation will showcase a recently released resistivity model of the southeast Australian lithosphere from Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) data collected over the last 7 years in collaborations between GA, GSNSW, GSV, GSSA and the University of Adelaide. For the first time, we image conductive regions at and below the base of the crust (>35 km depth) that may represent fossil fluid pathways along the Australian continental margin ~440 to 380 million years ago. The geometries of these conductive regions match those revealed in the upper crust by potential field and passive seismic data, and are a key part of crustal architecture predicted by the Lachlan Orocline model for the evolution of the southern Tasmanides. Conductive regions in the lower crust also correlate with known gold deposits, which may help to guide future mineral exploration in southeast Australia.

Register now: https://us02web.zoom.us/webinar/register/WN_tKJIKPMVQACF7sV7OQbYqw

PPDM: Navigating The Future of E&P Data Management Beyond 2020

Wednesday, August 26, 2020
0800
1700

The PPDM is holding its annual "Australian Petroleum Data Management conference" in a couple of weeks. The workshop will be held virtually, which allows the event to be within realistic reach of many more people than usual – hopefully all the people of the region who would be keen to attend some or all of it.  As an active member of both societies, I see member benefit in communicating this event to the  Petroleum and Minerals Exploration community of Australia at a discount: any member of the ASEG community who would like to attend either the workshop or the half day of short training courses is welcome to do so with a 25% discount on the already very low costs of attendance.

 

The workshop theme is "Navigating The Future of E&P Data Management Beyond 2020" and the workshop takes place on 2 successive half-days, on 26th and 27th August 2020.  Rock-bottom "early bird" rates available now.  Full details: https://lnkd.in/ebniq45.  Any question, anyone is welcome to contact me.

 

Prior to the workshop event is a half-day of short courses on August 25th to be delivered by North America-based experts:

1. Overview of the Open Subsurface Data Universe (OSDU) - Daniel Perna, EPAM Systems, USA

2. Introduction to Machine Learning - Lewis Matthews, West Texas Data Science Institute, USA

3. Introduction to Data Governance - Kevin Brunel, Brunel Analytics, USA
A half-day program at a low cost (very low for "early birds", available now).  Tuesday, August 25, 2020 (Australia Time), available online to all interested, anywhere.  Full details: https://lnkd.in/e-bvUJj.

For more information adn the discount details, please view the flyer here.

NSW branch webinar: State of the Arc: Long-Wavelength Geophysics and Macquarie Arc Basement

Wednesday, August 19, 2020
1800 (AEST)
1900 (AEST)

We are also happy to announce another new webinar by the NSW branch of ASEG on Wednesday 19 August, 6pm (AEST) for a talk by Bob Musgrave, Geological Survey of NSW.

State of the Arc: Long-Wavelength Geophysics and Macquarie Arc Basement

The Ordovician Macquarie Arc is the host of world-class Cu-Au mineralisation. But what lies beneath: sea-floor, thinned continent, or an older arc? Long-wavelength magnetic, gravity, MT and seismic features are the key to reconciling tectonic models, geochemistry, and geochronology of the arc.

Register now: https://us02web.zoom.us/webinar/register/WN_Sj1imrBlTCelHQELbEiwjA

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

Tuesday, August 11, 2020
1700 (AWST)
1800 (AWST)

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.

CSIRO EVENT: Our Knowledge Our Way in caring for Country

Thursday, July 30, 2020
1300 (AEST)
1400 (AEST)

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

Imposter Syndrome/ Inner critic workshop

Wednesday, August 12, 2020
1030 (AST)
1230 (AST)

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.

Helitem: New Technology in Airborne TEM for Deep and Covered Targets with Western Australia Examples

Thursday, August 20, 2020
1200 (AWST)
1300 (AWST)

Helitem2: New Technology in Airborne TEM for Deep and Covered Targets with Western Australia Examples

Adam Smiarowski, Chief Geophysicist at CGG

Date & Time: 20thAugust 2020; 12 – 1PM AWST

Please register here https://us02web.zoom.us/webinar/register/WN_x4nG-nqoRiqRmsGyXj485g

Abstract:

Exploration for targets at depth or targets obscured by conductive overburden have historically been a challenge with airborne EM methods. Although modern systems have been improved with greater primary transmitter moments, noise levels from receiver coil motion in the Earth’s ambient field has limited the detection of secondary target signals, especially at late times, and has limited the use of lower base frequencies. The new Helitem² system uses a patented low-noise receiver, a 50% duty cycle square pulse transmitter waveform, and low Tx base frequency, to achieve increased signal detectability for deep and covered targets.

Modeling and a series of demonstration surveys compared several helicopter-borne time-domain system configurations, including high-moment halfsine waveforms and low base frequency (15 Hz and 7.5 Hz)  50% duty cycle square waveforms.

Using a thin-plate, modelling showed that a low base frequency square pulse will have a significantly larger response than a half sine pulse at standard 30 Hz base frequency for a wide range of target conductances. At early times, the sharper (quicker) turn off of the square wave results in much more high-frequency energy, and therefore better signal, for weakly conductive targets, and better near-surface resolution. At the other extreme, the response from very conductive targets is determined by the area under the transmitter curve, so the low frequency square waves with 16 and 33 ms widths produces more than twice the signal as the half sine.

Demonstration survey line profiles and decay curves over the target and background locations confirmed this modelling for a 400 m deep target and variable overburden. The combination of pulse width, power, and low noise enabled the Helitem2 system to be effective at low base frequencies, where very late time data is beneficial for detecting strong and deep targets. The survey demonstrated that the redesigned Rx suspension system was able to reduce coil motion noise, enabling acquisition of high quality low base frequency data useful for detection of deep targets to very late times. The wide-pulse waveform was effective at energizing a moderately-conductive target, increasing signal level by a factor of 2 above a 6 ms pulse. This will be even more beneficial when exploring for strong conductive targets at depth. Prior to this Rx re-design, noise levels at low base frequencies was too high, and the data was not useful for target detection.

Examples from Western Australian are provided, illustrating data improvements of Helitem2 operating at 12.5Hz, over a previous survey at 25Hz.

Biography:

Adam has been involved with electrical methods for environmental and exploration applications for 15 years. Adam completed an MSc in Geophysics at RMIT University and PhD in Physics and Geology at the University of Toronto.  He has been involved with airborne EM research, both in frequency and time-domain, with CGG MultiPhysics for the past 9 years. has worked on applications related to reservoir modeling, seismic inversion and machine learning. 

WA tech night - nd-to-end seismic inversion of geostatistically complex reservoir facies models with deep convolutional neural networks

Thursday, August 6, 2020
1200 AWST
1300 AWST

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. 

Structural Geology in Seismic Interpretation - SEG Virtual Course

Monday, July 20, 2020
0900
1300

Structural Geology in Seismic Interpretation by Shankar Mitra, University of Oklahoma

The course is designed for geophysicists working on seismic interpretation of complex structures, who need to understand the seismic expression of structures in petroleum basins, and correctly apply structural models and techniques to seismic interpretation. Full details can be found here.

 

Date:

20-23 July 0900 – 1300 hours per day (Malaysia time)

 

Course Outline:

As attached

 

Pricing:

Individual: US$ 390 per person

Group of 2-10: US$325 per person

Group of 11 and above: US$295 per person

Student: US$ 100 per person

 

For individual registration, please register directly at: https://seg.org/shop/products/detail/204434173

 

For group registration, please send in the participants details together with invoicing details directly to me. Once we received these details we will issue an invoice for company group registrations.

 

Virtual Course Platform:

GotoWebinar

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