Mineral and petroleum potential in the South Nicholson region, and the NDI Carrara 1 stratigraphic drill hole

Jarrett, Amber1,2, Bailey, Adam1, Carr, Lidena1, Henson, Paul1, Schofield, Anthony1,2, O’Rouke, Angela1,2, Roach, Ian1,2, Budd, Anthony1,2, Munson, Tim3, Williams, Ben3, Symmons, Jack3, Close, Dorothy3

1Geoscience Australia, Canberra, Australia, 2MinEx CRC, Canberra, Australia, 3Northern Territory Geological Survey, Darwin, Australia

The MinEx CRC-led National Drilling Initiative (NDI) is the world’s largest mineral exploration collaboration designed to undertake precompetitive geoscience research in underexplored, but potentially prospective regions. One of the first NDI projects is being undertaken in the South Nicholson region of the Northern Territory (NT) as a collaboration with Geoscience Australia and the Northern Territory Geological Survey.

The South Nicholson Basin, and underlying Lawn Hill Platform region, have the potential for sediment‑hosted base metal mineral deposits including critical minerals and hydrocarbons. The region is poorly understood compared with the neighbouring resource‑rich areas of the McArthur Basin and the Mount Isa Province. Providing baseline data in frontier basins is essential as legacy data coverage can often be inadequate for making investment decisions, particularly with new commodities where exploration may not yet have provided the required information.

In 2017, Geoscience Australia acquired the L210 South Nicholson Deep Crustal Seismic Reflection Survey. This survey demonstrated the existence of an approximately 1550 km2 sedimentary depocentre underlying the surface sedimentary rocks of the Georgina Basin, and coincident with a prominent gravity low. This depocentre has been termed the ‘Carrara Sub‑basin’ and its successions may host a continuation of the resource-rich rocks located on the northern Lawn Hill Platform of northwest Queensland, in addition to South Nicholson stratigraphy that has never been sampled by drill core.

MinEx CRC and its partners seek to better understand the geology and resource potential of the Carrara Sub‑basin through the drilling of the first deep vertical stratigraphic borehole in the region –the NDI Carrara 1 stratigraphic borehole. This borehole has been designed to answer key scientific questions suggested by Geoscience Australia and the Northern Territory Geological Survey including determining geological and geochemical characteristics of sedimentary units from fresh drill core, identifying any evidence of alteration or fluid flow, and finally determining whether there are favourable indicators for the presence of mineral or petroleum systems. To address these questions, both physical samples (e.g. drill core and cuttings) and downhole data (e.g. wireline geophysical data) will be acquired over the entire borehole interval, to a depth of about 2000 m.

Drilling of NDI Carrara 1 is set to be completed by the end of 2020. This presentation will provide a rationale for drilling the NDI Carrara 1 stratigraphic borehole and will present preliminary data generated through drilling.

The South Nicholson NDI has already provided and integrated new geoscience data and knowledge in the region, and NDI Carrara 1 will allow for direct testing of resource potential. This precompetitive data is fundamental to underpinning increased industry investment and sustainable economic development in this greenfield region of northern Australia.


Biography

Amber Jarrett is a Geochemist in the Minerals, Energy and Groundwater Division, Geoscience Australia. Her research interests include petroleum geochemistry, basin hosted resource potential, isotopes, biomarkers and early life. Amber graduated with a BSc (Hons) in 2008, majoring in both Geology and Biology, and a PhD in 2014 from ANU.

About the GSA

The Geological Society of Australia was established as a non-profit organisation in 1952 to promote, advance and support Earth sciences in Australia.

As a broadly based professional society that aims to represent all Earth Science disciplines, the GSA attracts a wide diversity of members working in a similarly broad range of industries.