Optically stimulated luminescence (OSL) dating of sand sheets provides a chronology of the largest tsunamis in western Thailand over the late Holocene. Four sand sheets deposited by pre-2004 tsunamis were dated by luminescence to 380 ± 50, 990 ± 130, 1410 ± 190 and 2100 ± 260 years ago (at 1-sigma precision). These compare with previous radiocarbon ages of detrital bark high in buried soils (Jankaew et al., 2008), which suggest that the most recent large-scale predecessor to the 2004 tsunami occurred soon after 550-700 cal BP, and that at least three such tsunamis occurred over the past 3000 years. Concordant OSL ages from successive beach ridges (1600 ± 210 to 2560 ± 350 years ago) and tidal flat deposits (2890 ± 390 years ago) provides a set of limiting maximum ages for sand sheet deposition which, when combined with the sand sheet ages, provide a robust average for tsunami recurrence. The ages imply that between 350 to 700 years separates successive tsunamis on the Andaman coast of Thailand with an average tsunami recurrence interval of 550 years. These results show OSL can provide independent estimates of tsunami recurrence for hazard analysis, particularly in areas where suitable material for radiocarbon dating is unavailable.

This report describes the ornamental stones used in the ground floor foyer of the Geoscience Australia building. There are three ornamental stones used. The flooring tiles are basalt. The 'fault' line through this is a polished norite and the blade walls are covered by a Persian red Travertine. Investigations have established that the basalt and norite are from Australian quarries and the travertine is from an unknown source overseas possibly Italy.

Legacy product - no abstract available

Canning Basin Chart updated August 2013

As part of Geoscience Australia's 2002-2004 work program, the Petroleum and Marine Division initiated a collaborative study of the Otway Basin (Figure 1) with Primary Industries and Resources SA (PIRSA) and the Department of Primary Industries (DPI), Victoria. The aim of the project was to enhance the petroleum prospectivity of the basin through an improved understanding of depositional systems, integrated petroleum systems analysis and enhanced access to basic datasets critical to the exploration industry. Major project work components included seismic- and well-interpretation to construct a new regional chronostratigraphic framework for the basin (Figure 2), geochemistry and geohistory modelling to document regional petroleum systems elements (Boreham et al ., 2004), and biostratigraphy to refine age-control, biozonations and correlations within the basin (Krassay et al ., 2004). Biostratigraphic work for the Otway Basin Project involved a major program of new sampling, processing and palynological analysis combined with a thorough review of existing biostratigraphic reports and data. Collection, processing and preparation of new samples were conducted in-house by Geoscience Australia staff. New palynological analyses were carried out by Morgan Palaeo Associates on a commercial contract basis. This Record (CD-ROM) contains consultants palynological reports (Microsoft Word) and digital data files as originally submitted (wmf and dex formats) and as updated and standardised (csv format) for over 200 new samples collected from 14 selected Otway Basin wells (Table 1). This Record also contains revised palynological data files (csv format) for 18 Otway Basin wells (Table 2). Revision and updating of palynological data from existing reports and new consultants reports involved initial quality-assurance and quality-control of the data followed by updating of synonyms and systematics to comply with a standardised taxonomy. Revised data files contained in this Record adhere to a standardised taxonomy in current use at Geoscience Australia. Revised data files are presented in a csv format (Excel spreadsheets).

This report presents new geochronological results for five uranium deposits in Australia, detailing the timing of uranium mineralisation in relation to regional geological events. The purpose of the study is to better constrain ore genetic and exploration models for these uranium mineral systems, and ultimately to improve understanding of the uranium resource potential of the Australian continent. The work was carried out under the auspices of the Onshore Energy Security Program. Each of the five uranium deposits represents a different style of mineralisation within three broad families of uranium mineral systems: magmatic-related, basin-related, and metamorphic-related. The results contribute to the current paucity of age data for uranium deposits in Australia, and for most of the deposits the new dates are the first reported direct ages for mineralisation or associated alteration.

Bonaparte Basin biostratigraphic chart

Northern Carnarvon Basin Biozonation and Stratrigraphy, 2008, Chart 34

The contemporary crustal stress regime in south-eastern Australia can be traced back to the terminal Miocene. Increased coupling of the Australian and Pacific Plate boundary at this time resulted in regional-scale tilting, local uplift and erosion, and in the formation of unconformities in southern Australian basins. In the onshore Gippsland Basin the unconformity surface is overlain by an extensive sheet of fluvial sediment known as the Haunted Hill Formation (HHF). Open folds and flexures developed within the HHF over blind reverse and reverse oblique faults provide a record of deformation spanning much of the neotectonic period. The predominance of flexures and folds rather than discrete faulting at the surface complicates the assessment of slip rates over the last few seismic cycles. However, ages from an undeformed fill terrace bordering the Morwell River and crossing the Morwell Monocline suggest that it has been a minimum of 70 ka since the last deformation event on at least this structure. Stream profiles crossing the Snake Ridge, Yallourn and Rosedale Monoclines similarly reveal no evidence for recent tectonic displacement. Cosmogenic radionuclide (10Be and 26Al) burial ages of siliceous sediments sampled from tectonically uplifted HHF on the Yallourn, Morwell and Snake Ridge Monoclines provide constraint on the long-term evolution of these structures. Combined with stratigraphic and tectonic records from the offshore Gippsland Basin, these data provide a basis for informed seismic hazard assessment.

Widespread reductions in the thickness and extent of Antarctic ice shelves are triggering retreat, acceleration and increased discharge of marine-terminating glaciers. However, while the impacts of recent ice-shelf changes are now well documented, their role in modulating past ice sheet dynamics – especially at a resolution required to identify drivers of change and test ice sheet models - remains poorly constrained. This reflects two persistent issues: (i) the effective discrimination between sediments and landforms deposited in a sub-ice-shelf setting from other glacimarine environments, and (ii) challenges associated with dating these records. Here we summarise recent progress in deciphering the ‘geological imprint’ of Antarctic ice shelves, including important advances in dating methods and the proxies required to reconstruct the drivers of change. Despite this improved ‘toolbox’ for establishing ice shelf presence and absence, we recognise several challenges that need to be overcome if we are to fully exploit the palaeo record. <b>Citation:</b> Smith, J.A., Graham, A.G.C., Post, A.L. et al. The marine geological imprint of Antarctic ice shelves. <i>Nat Commun</i> <b>10</b>, 5635 (2019). https://doi.org/10.1038/s41467-019-13496-5