New SHRIMP U-Pb detrital zircon geochronology on Mesoproterozoic and Paleoproterozoic siliciclastic rocks from the South Nicholson region, in concert with recently acquired complementary regional geophysical datasets, have enabled comprehensive revision of the regional Proterozoic tectono-stratigraphy. The identification of analogous detrital zircon spectra of units deposited in half-graben hanging walls of major east-northeast-trending extensional faults, offers compelling evidence for regional tectono-stratigraphic correlation. This study sampled units from the hanging walls of the Benmara, Bauhinia, and Maloney-Mitchiebo (east-northeast-trending) faults, which identified immature proximal lithofacies hosting a small yet persistent population of ca 1660-1640 Ma aged zircon and lack Mesoproterozoic detritus. The timing of this event is consistent with deposition coincident with crustal extension during the extensional River Event at ca 1640 Ma, an event previously identified from the Lawn Hill Platform in western Queensland. This finding suggests the hanging wall sequences are chrono-stratigraphically equivalent to the highly prospective sedimentary rocks of the Isa Superbasin, host to world-class sediment-hosted base metals deposits across western Queensland and northeastern Northern Territory. Subsequent inversion of the extensional faults resulted in development of south-verging thrusts, and exhumation of late Paleoproterozoic hanging wall siliciclastic rocks through overlying Mesoproterozoic South Nicholson Group rocks as fault propagated roll-over anticlines. These geochronology data and interpretations necessitate revision of the existing stratigraphy and the renaming of a number of stratigraphic units in the South Nicholson region. Accordingly, the distribution of the highly prospective late Paleoproterozoic units of the McArthur Basin, Lawn Hill Platform and Mount Isa Province is greatly expanded across the South Nicholson region. These findings imply that the underexplored South Nicholson region is a highly prospective greenfield area for energy and mineral resources.

A comprehensive geochemical program was carried out on rock samples collected in the NDI Carrara 1 drill hole, the first stratigraphic test of the newly discovered Carrara Sub-basin located in the South Nicholson region of northern Australia. The drill hole recovered continuous core from 284 m to total depth at 1750 m and intersected approximately 1120 m of Proterozoic sedimentary rocks, unconformably overlain by 630 m of Cambrian Georgina Basin carbonate-rich rocks. Total organic carbon (TOC) contents from Rock-Eval pyrolysis highlight the potential for several thick black shales to be a source of petroleum for conventional and unconventional plays. Cambrian rocks contain an organic-rich section with TOC contents of up to 4.7 wt.% and excellent oil-generating potential. The Proterozoic section is overmature for oil generation but mature for gas generation, with potential for generating gas in carbonaceous mudstones showing TOC contents up to 5.5 wt.% between 680 and 725 m depth. A sustained release of methane (up to 2%) recorded during drilling from 1150 to 1500 m suggests potential for an unconventional gas system in the Proterozoic rocks from 950 to 1415 m depth, which exhibit favourable organic richness and thermal maturity. The Proterozoic rocks, which are comparable in age to the sediment-hosted deposits of the Century Mine, contain local occurrences of lead, zinc and copper sulfide minerals providing hints of mineralisation. The combined geochemical results offer the promise of a potential new resource province in northern Australia.

NDI Carrara 1 is a deep stratigraphic well completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI), in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first stratigraphic test of the Carrara Sub-basin, a newly discovered depocentre in the South Nicholson Region. The well intersected Proterozoic sediments with numerous hydrocarbon shows, likely to be of particular interest due to affinities with the known Proterozoic plays of the Beetaloo Sub-basin and the Lawn Hill Platform, including two organic-rich black shales and a thick sequence of interbedded black shales and silty-sandstones. Alongside an extensive suite of wireline logs, continuous core was recovered from 283.9 m to total depth at 1750.8 m, providing high-quality data to support comprehensive analysis. Presently, this includes geochronology, geochemistry, geomechanics and petrophysics. Rock-Eval pyrolysis data demonstrate the potential for several thick black shales to be a source of hydrocarbons for conventional and unconventional plays. Integration of these data with geomechanical properties highlights potential brittle zones within the fine-grained intervals where hydraulic stimulation is likely to enhance permeability, identifying prospective Carrara Sub-basin shale gas intervals. Detailed wireline log analysis further supports a high potential for unconventional shale resources. Interpretation of the L210 and L212 seismic surveys suggests that the intersected sequences are laterally extensive and continuous throughout the Carrara Sub-basin, potentially forming a significant new hydrocarbon province and continuing the Proterozoic shale play fairway across the Northern Territory and northwest Queensland.

The Prydz Bay coast, including the Larsemann Hills, features relatively extensive bedrock exposures of interest because of the proximity to a hypothesized suture associated with Gondwana assembly. Critical units are the basement Søstrene Orthogneiss (1,126 ± 11 Ma protolith) and cover Brattstrand Paragneiss (maximum depositional age 1,023 ± 19 Ma). The two units share a polymetamorphic history with events at ~900 Ma (D 1 ) and ~530 Ma (D 2‐4 ). Here we present electron microprobe dates of monazite growth zones and Perple_X pseudosection models of granulite‐facies rocks from the Søstrene Orthogneiss, Brattstrand Paragneiss, and D 2‐4 pegmatites of the Larsemann Hills. We propose a scenario for Cambrian metamorphism involving a peak stage at 6–7.5 kbar and 800–860°C (D 2 convergence), melt crystallization and garnet breakdown during decompression to early retrograde conditions of 3–4.5 kbar and 700–750°C (D 2 convergence, D 3 extension), and a late retrograde stage with decompression and cooling to 3–3.5 kbar and 550–650°C (D 4 ). We combine monazite chemistry with phase assemblages predicted by pseudosection modelling to link specific monazite growth domains to individual tectonic stages. Monazite domains containing moderate Th and low to moderate Y are interpreted to be preserved from the prograde path when garnet was stable, and constrain the timing of prograde metamorphism at 536 ± 4 Ma. High‐Th, low‐Y domains, dated at 527 ± 2 Ma, represent the earliest stages of post‐peak melt crystallization. Monazite domains with elevated Y and low‐moderate Th are interpreted to represent monazite growth during garnet breakdown at 514 ± 2 Ma. Our monazite ages, combined with published biotite Ar–Ar cooling ages, yield a two‐stage history of cooling at 3–8°C/Myr from ~530 Ma to ~510 Ma followed by cooling at 18–25°C/Myr from ~510 Ma to ~490 Ma, corresponding to 0.2–0.6 mm/yr of exhumation. This duration of granulite‐facies metamorphism in the Larsemann Hills is consistent with estimates for Precambrian granulite facies metamorphic complexes elsewhere.

Abstract. Understanding past retreat of Antarctic ice margins provides valuable insight for predicting how ice sheets may respond to future environmental change. This study, based on high resolution multibeam bathymetry from the nearshore region of the Windmill Islands, East Antarctica, reveals a style of retreat that has been rarely observed on the Antarctic margin. A suite of seafloor features record the final retreat stages of a relatively thin, and increasingly fractured tidewater glacier confined within narrow troughs and embayments, forming a suite of features more typical of warm-based ice, but occurring here in a region of cold-based ice with limited surface meltwater production. The pattern of moraines and crevasse squeeze ridges, reveals strong topographic and substrate control on the nature of ice sheet retreat. Topographic control is indicated by fine-scale variability in the orientation and distribution of glacial landforms, which show that the seabed topography influenced the shape of the ice margin, caused deflection of ice flow and led to the separation of flow downstream from topographic highs. The availability of water saturated marine sediments within the troughs and depressions also had a profound effect on the landform record, facilitating the construction of moraines and crevasse squeeze ridges within topographic lows, corresponding to areas of modern sediment accumulation. Surrounding areas of crystalline bedrock, by contrast, acted as sticky spots and lack a well-developed landform record. This seafloor glacial record emphasises the importance of understanding the bed topography and substrate when predicting the nature of ice margin retreat and provides new perspectives for understanding the stability of the East Antarctic margin.