NSW

Titles &  Presenters:

Enhancing statewide geophysics with high resolution company data - Dr Sam Matthews (GSNSW)

Proposed NSW geophysical acquisition 2021-2022 - Astrid Carlton (GSNSW)

Date & Time: Wednesday 20th October 2021, 6:00 pm to 7:00 pm AEDT

Registration: https://us02web.zoom.us/webinar/register/WN_fWZnFRp1Q2q9wOapDGGHkA

Overviews:

Sam’s talk will provide a behind the scenes look at the creation of enhanced statewide geophysical merges incorporating high resolution company data. Following the QA/QC and metadata harvest from decades of legacy geophysics data, a specially created algorithm is applied to provide a quantitative aid in survey selection for inclusion in the merges. A small data workshop is included which highlights how all open-file geophysical data in NSW can be accessed for free through our online portal MinView.

Astrid’s talk will detail the expansive array of regional geophysics occurring throughout NSW from 2021 and into the future. The recent completion of the Cobar AEM and AMR surveys, as well as the Mundi AEM survey are only the tip of the iceberg in NSW. A wealth of regional geophysical surveys spanning a wide range of techniques are also in the works and promise exciting data.

The next NSW technical meeting will be held on Wednesday 16th June (apologies for the short notice), we will also be livestreaming on zoom and it will be uploaded to ASEG's YouTube channel later. Please see details below:

Presenter:          Dr Stuart Clark (UNSW) and Patrick Makuluni (UNSW)

Topic:                  Tilting of the Australian Continent: New Evidence from the Subsidence and Deposition History of the Northern Carnarvon Basin

Time:                   5:30 for 6pm start

Address:             Level 2, Club York (99 York St, Sydney. Room 'York 2')

Zoom registration:         https://us02web.zoom.us/webinar/register/WN_Qf8x55wZT2SSUPOi3nBYuQ

Meeting registration:    https://www.surveymonkey.com/r/YBRXQND by Tuesday 15th June - due to COVID restrictions we require a registration for in-person meetings, see the attached document for Club York's COVID statement. If you have trouble registering please email nswsecretary@aseg.org.au 

Summary:

Studies of the global sea-level changes, plate kinematics, marine inundation, and morphology of the continental shelves suggest that the Australian continent has been tilting north eastwards since the Late Cretaceous. Our work investigates the direct impact of this phenomenon and the preceding tectonic events on the evolution of the Northern Carnarvon Basin evolution and its hydrocarbon resources. We use backstripping and decompaction techniques to develop subsidence, sedimentation, and porosity evolution models for the basin, which sits on the axis of the tilt. The goal is to highlight the spatial and temporal variation of subsidence and sedimentation rates, then give insights into the factors that created accommodation space for sediments. Then assess their impacts on the porosity of the Early Cretaceous reservoirs within the basin. The results reveal a north-eastward shift of subsidence and sedimentation rates from the Early Jurassic to the present in the region. In the Early Jurassic to Early Cretaceous, this variation was caused by the Palaeozoic-Mesozoic rifting events that produced higher tectonic subsidence (~3km) and higher sediment supply in the southwestern Exmouth and Barrow sub-basins, with reducing intensity in the northeastern direction towards Dampier and Beagle Sub-basin. From cretaceous to the present, subsidence and sediment distribution were impacted by the dynamic topography and the northeastwards tilting of the Australian continent. Subsidence along the NE-SW transect and the porosity evolution model results also demonstrate the tilting occurring in these sub-basins.

The next technical meeting will be held on Wednesday 19^th May, we will also be livestreaming it on zoom only (the presentation will not be available for viewing later). Please see details below:

Presenter:          Chris Alfonso (USYD)

Topic:                  The influence of dynamic topography, climate, and tectonics on the Nile River source-to-sink system

Time:                   5:30 for 6pm start

Address:             Level 2, Club York (99 York St, Sydney. Room 'York 2')

Zoom registration:         https://us02web.zoom.us/webinar/register/WN_x9aipncxT3Wn4TIQdr06AA

Meeting registration:    https://www.surveymonkey.com/r/TYFG2GM by Monday 17^th May – due to COVID restrictions we require a registration for in-person meetings. If you have trouble registering please email nswsecretary@aseg.org.au 

Summary:

Understanding the more than 30 Myr history of the Nile River can provide great insight into the evolution of one of the world's largest river systems and the major hydrocarbon reserves of the Nile Delta. This work builds on previous studies which explored the relationship between the river's course and the dynamic topography of Northeast Africa by considering additional possible influences on the Nile's evolution such as climate change and tectonics. These factors are incorporated into a numerical landscape evolution and stratigraphic modelling framework which makes use of the Badlands software package (https://badlands.readthedocs.io) to test the effects of multiple different scenarios for each factor. The analysis of model results involves one of the first applications of the techniques of sequence stratigraphy to a realistic numerical model. These results show that while dynamic topography, along with climate change, likely played a significant role in the Nile's history, tectonic events – including the formation of the Red Sea Hills and uplift and volcanism of the Ethiopian Plateau – appear to have had the strongest influence on the river's evolution.

Light refreshments will be available as usual, hope to see you there.

Title: Shallow mantle convection beneath West Africa and source to sink at continental margins: A novel approach to reservoir prediction in offshore deep-water settings

Presenter: Dr Bhavik Harish Lodhia (UNSW)

Abstract:

Deep-water settings are prevalent in many of the world’s frontier basins. To better focus exploration spend in today’s challenging environment and predict reservoirs, a novel approach to close the loop between onshore denudation and offshore sediment deposition is required. Sedimentary flux measurements, regional subsidence patterns, tomographic models and simple isostatic calculations are combined to constrain the history of offshore solid sedimentary flux and sub-plate support of the Mauritanian Basin. We combine seismic reflection and well data along the West African margin with shear wave tomography and the uplift and magmatic history of the Cape Verde Rise to constrain thermal, spatial and temporal scales of upper mantle convection. Predictions of solid sedimentary flux to the Mauritanian Basin calculated by inversion of continental drainage are compared to observations in the Chinguetti field of the Mauritanian Basin.

Bio: Bhavik moved to Australia from the United Kingdom earlier this year and is currently a Postdoctoral Fellow in Energy Technology and Geophysics at UNSW. Bhavik graduated with a PhD in Geology and Geophysics at Imperial College London in 2019 and completed a masters/bachelors degree in Earth Sciences at St. Anne's College, University of Oxford in 2014. His work has focused on basin dynamics, geodynamics, sediment source to sink and petroleum systems modelling.

Register: https://us02web.zoom.us/webinar/register/WN_-_AXVmqGT5GGGUrJw-VODA

Attend in-person

Time:                    5:30 for 6pm start

Address:              Level 2, Club York (99 York St, Sydney. Room 'York 2')

Meeting registration:      https://www.surveymonkey.com/r/2V6JM9F by Sunday 18th April - due to COVID restrictions we require a registration for in-person meetings. If you have trouble registering please email nswsecretary@aseg.org.au 

Title:    An explanation for the distribution of Broken Hill style mineralization invoking dense rift-related igneous intrusions.

Presenter: Peter Gunn (MSc, PhD)
Day and Date of Event:    Wednesday 17th March 2021
Start and finish times:6:00 pm to 7:00 pm AEST

ABSTRACT
This talk is a revised version of an invited keynote presentation made at a Broken Hill Symposium in 2015.
 
The talk will suggest explanations for:
 
-                      the gravity field of the Broken Hill area
-                      the distribution and origin of the Ag-Pb-Zn mineralisation
-                      the distribution and origin of the Cu mineralisation
-                      the magnetic field of the Broken Hill area
-                      the original structure of the Broken Hill area
-                      the present structure of the Broken Hill area
-                      the topography of the Broken Hill area
-                      and - gives guidelines for exploring for Broken Hill type deposits.
 
Various workers have suggested that the Broken Hill area originated as a rift that was subsequently metamorphosed and intensively deformed. The presenter agrees with this idea and, based on his experiences with many well studied rifts elsewhere in the world, largely in the context of hydrocarbon exploration, identifies subtleties that do not appear to have been appreciated as applying to the Broken Hill rift.

Registration link: https://tas.currinda.com/register/event/2198

Clive Foss and Jim Austin at CSIRO Mineral Resources on From Tenterfield to Mars: Magnetic Modelling with Terrain.

  Register now: https://us02web.zoom.us/webinar/register/WN_m8LruZUdRji2OG23PSPCIA

Brought to you by NSW on Wednesday 21 October, 6pm (AEST) for a talk by Peter Hatherly.

Stranded stream channels investigated by LiDAR mapping, some geophysics and good old leg work. Insights into the Lapstone Structural Complex west of Sydney.

In the contemporary parlance, the western boundary of what the media call the Sydney Basin is the Lapstone Structural Complex. The front range of the Blue Mountains. This abrupt escarpment rises to a maximum height of 600 m above the Cumberland Plain and forms an impressive boundary to the Blue Mountains beyond.

Geologists identified the monoclines and faults associated with the LSC as early as the nineteenth century but an understanding of the exact nature of the structure and its timing is still not clear. In this talk I take note of evidence of stranded channels evident in detailed LiDAR mapping, the occurrence of river gravels now high above the Nepean River and seismic refraction results within the Thirlmere Lakes, a curious river system within the southern extension of the LSC.

My suggestion is that in its present form, the LSC is probably no older than 10 million years.

Register now: https://us02web.zoom.us/webinar/register/WN_klquuUL_Q3a39DbZUM-9rQ

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

The NSW Branch of the ASEG invite you to join us on ZOOM for the next talk in the ASEG Webinar Series. 

Please join us on Wednesday 20th May, 6:00 pm (AEST) for a talk by Simon Williams from GBG Australia.

Geophysical Characterisation for the Dredging of the Marine Industry Park, Darwin

This presentation covers the use of multiple marine geophysical methods to help characterise the geology and geotechnical challenges for preliminary design of dredged access channels to a proposed marine industry development site in Darwin Harbour. The main geophysical methods utilised to characterise the geological materials where single-channel seismic reflection and densely spaced continuous marine seismic refraction. 

Please bring your own drinks and nibbles.

Register Now: https://us02web.zoom.us/webinar/register/WN_HN4mk5BkQxW3bMGrvthdSw  

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