The first edition ACE - Australian Continental Elements dataset is a GIS representation of the lithosphere fabrics of the Australian plate, interpreted from linear features and associated discontinuities in the gravity anomaly map of continental Australia (Bacchin et al., 2008; Nakamura et al., 2011) and the global marine gravity dataset compiled from satellite altimetry (Sandwell & Smith, 2009). It should be used in context with these input data sources, at scales no more detailed than the nominal scale of 1:5 000 000.

This collaborative project between Geoscience Australia (GA) and CSIRO aims to use physicochemical measurements, collected from surface overbank sediments as part of the National Geochemical Survey of Australia (NGSA) project, to help validate the ASTER multispectral geoscience maps of Australia. Both data sets have common information including that related to the surface abundance of silica, aluminium, iron, clay, sand and volatiles (including carbonate). The ASTER geoscience maps also provide spatial information about trends of mineral composition, which are potentially related to pH and oxidation state.

Australia is bounded on three sides by passive continental margins, a legacy of Gondwana breakup as first India and then Zealandia, followed by Antarctica, separated from Australia during the Late Jurassic-Early Cretaceous through to earliest Oligocene. As with most other rifted continental margins, breakup along each of these three margins occurred episodically, controlled by a number of factors including mantle rheology, pre-existing lithospheric and basement structure, and the direction of crustal extension prevailing at any one time during successive stages of continental rifting. Resulting post-rift passive margin geometries are consequently highly segmented and characterised by abrupt changes in orientation along strike that commonly coincide with pre-existing basement structures or crustal-scale heterogeneities across which there is a commensurate change in offshore basin architecture and normal fault patterns. Mapping of these heterogeneities in geological and geophysical datasets combined with a growing realisation that many of these basement features extend all the way to the ocean-continent boundary has focussed attention on the extent to which these same crustal structures may also have influenced the distribution and pattern of ocean floor fracture zone development. A prominent re-entrant along Australia's 4000-km long southern rifted margin marks the site of an early Paleozoic crustal-scale basement structure whose N-S orientation was optimal for reactivation during a switch in the direction of extension from NW-SE to N-S during the closing stages of continental rifting from about 55-47 Ma onward. This structure evolved from a continental transform boundary into the Tasman Fracture Zone with consequent development of a sheared continental margin along the western margin of the South Tasman Rise analogous to that formed off the Ghanaian coast during the separation of Africa from South America. As with its West African counterpart, seismic reflection profiles point to a strong strike-slip influence on basin geometry with en echelon development of elongate, narrow depocentres bounded by discontinuous steep to subvertical faults. Equally spectacular pull-apart basins associated with the 1500km-long Wallaby-Zenith Fracture Zone off Western Australia are similarly developed in thinned continental crust but, unlike the basins associated with the South Tasman Rise, they have been better seismically imaged and contain a substantially greater thickness of sediment (up to 5 seconds TWT). Interpreted seismic sections across the Zeewyck Sub-basin beneath the Valanginian breakup unconformity show a complex network of deep sedimentary basins bounded by steep faults and blocks of elevated older basement (positive flower structures) across which there is only limited lateral continuity in stratigraphy. Sedimentary sequences immediately above the breakup unconformity thicken into the basin axis and exhibit wedge-like geometries consistent with detritus shed from the adjacent basement highs as the sheared continental margin evolved and the associated spreading axis migrated oceanward. A period of basin-wide folding and faulting accompanied by uplift and erosion brought this phase of basin formation to a close and possibly occurred in response to transpression immediately prior to the onset of full drift. Fabrics in the adjacent N-S striking Pinjarra Orogen and related Darling Fault played an important role in localising extensional strain during formation of the Zeewyck Sub-basin and greater Perth Basin.

Since the early 2000s Geoscience Australia has been compiling new seamless national continental scale geological maps. The first edition of a seamless 1:1 000 000 scale surface geology map of Australia was released in 2008 [1] and the latest edition released in 2012 [2]. This work draws extensively from available geological mapping in Australia, primarily at the scales of 1:250 000 and 1:100 000 with the addition of some special regional scale maps. The digital GIS dataset is linked to other national geoscience databases at Geoscience Australia, including the Australian Stratigraphic Units Database. In September 2013, Geoscience Australia released the first national Geological Provinces dataset [3]. Geoscience Australia's Geological Provinces Database captures detailed information such as age, stratigraphy, lithology, mineral resources, and relations to other provinces. It also captures outlines of the full (ie, concealed) extent and outcropping extent of a province. As part of Geoscience Australia's contribution to Searching the Deep Earth [4], current continental scale digital geological mapping in Geoscience Australia includes production of a new national bedrock geological map at 1:2 500 000 scale with stratigraphic units information that can be linked with other national geoscience databases, basement geology, and a national regolith landforms coverage. Looking ahead, a goal is to produce seamless, continental scale basement or 'solid' geology maps for a variety of depth/time slices. A recent step towards this goal has been the production of a map of Mesoproterozoic and older basement geology for a large region of central Australia, from the eastern Yilgarn Craton of Western Australia across the Musgrave and southern Arunta Provinces to the Queensland border.

Mineral deposits, although geographically small in extent, are the result of processes-which together form a mineral system-that occur, and can be mapped at, a variety of scales, up to craton-scale and larger. The mineral system approach has the benefit that in it focuses on critical processes and can include larger scales not always considered. Understanding the four-dimensional evolution of the crust, for example, is important, as it can provide critical constraints on the geodynamic history, the lithospheric architecture and development, and potentially identify metallogenic terranes. Constraining the nature and evolution of the crust is not easy, however, given its largely inaccessible nature. Just as the study of basaltic rocks has provided insight into the earth's mantle, granites, provide a window into the middle and lower continental crust. Studies of these rocks are enhanced by the use of isotopic tracers (e.g., U-Pb, Sm-Nd, Lu-Hf), long used to provide constraints on geological processes and components involved in those processes.

The 'Major crustal boundaries of Australia' map synthesizes more than 30 years of acquisition of deep seismic reflection data across Australia, where major crustal-scale breaks have been interpreted in the seismic reflection profiles, often inferred to be relict sutures between different crustal blocks. The widespread coverage of the seismic profiles now provides the opportunity to construct a map of major crustal boundaries across Australia. Starting with the locations of the crustal breaks identified in the seismic profiles, geological (e.g. outcrop mapping, drill hole, geochronology, isotope) and geophysical (e.g. gravity, aeromagnetic, magnetotelluric) data are used to map the crustal boundaries, in map view, away from the seismic profiles. For some of these boundaries, a high level of confidence can be placed on the location, whereas the location of other boundaries can only be considered to have medium or low confidence. In other areas, especially in regions covered by thick sedimentary successions, the locations of some crustal boundaries are essentially unconstrained. The 'Major crustal boundaries of Australia' map shows the locations of inferred ancient plate boundaries, and will provide constraints on the three dimensional architecture of Australia. It allows a better understanding of how the Australian continent was constructed from the Mesoarchean through to the Phanerozoic, and how this evolution and these boundaries have controlled metallogenesis. It is best viewed as a dynamic dataset, which will have to be further refined and updated as new information such as seismic reflection data becomes available.

The mechanism and uplift history of Australia's southeastern highlands has long been debated. End member models account for the topography as a down warped relict of an ancient plateau or a consequence of uplift associated with either rifting along the eastern margin or Cenozoic volcanism. All of these models assume present-day elevation is a consequence of isostatic equilibrium at the base of the crust. An analysis of the relationship between gravity and topography in the spectral domain shows the admittance at wavelengths longer than those controlled by flexure is ~50 mgal km-1. This value is characteristic of dynamic support arising from thermal anomalies beneath the plate predicted by multiple mantle convection simulations and observed over Africa, Antarctic and the Pacific Ocean. Division of long-wavelength filtered gravity by this admittance value suggests the southeastern highlands are supported by 400-900 m. The morphological expressions of this support are the Great Escarpment and major knick zones on rivers such as the Snowy. The temporal evolution of this support can be determined by exploiting longitudinal river profiles since their shape is controlled by uplift and modulated by erosion. By applying the well-known detachment limited stream power law to model erosion uplift histories can be extracted provided erosional parameters can be constrained. By calibrating the erosional parameters using incision rates along the Tumut River and Tumbarumba Creek as well as palaeoelevations of basalt flows the uplift history of the southeastern highlands can ascertained directly from the landscape. Our results show uplift of the southeastern highlands occurred in two phases associated with Cretaceous age rifting resulting in Tasman Sea floor spreading and Cenozoic volcanism. The latter event accounts for the observed amplitude of present-day dynamic topography thereby suggesting Cenozoic uplift occurred from an unperturbed isotactic elevation. Since Cretaceous rifting along the southeastern margin occurred over a cool mantle given the oldest oceanic floor is thinner than the global average it is unlikely that rift related uplift is a consequence of mafic underplating. The most likely driver for this earlier phase of uplift is emergence of eastern Australia from a dynamically drawdown position which has been inferred to explain the widespread mid-Cretaceous marine inundation of Eastern Australia. Therefore it is likely that both uplift events are controlled by changes in the thermal state of the mantle as opposed to changes in crustal thickness and density. This history of vertical motions is consistent with long-term river incision rates, basin sequence stratigraphy and thermochronological studies.

2014 Open Day Promotional Material

Tsunami inundation models provide fundamental information about coastal areas that may be inundated in the event of a tsunami. This information has relevance for disaster management activities, including evacuation planning, impact and risk assessment, and coastal engineering. A basic input to tsunami inundation models is a digital elevation model-that is, a model of the shape of the onshore environment. Onshore DEMs vary widely in resolution, accuracy, availability, and cost. Griffin et al. (2012) assessed how the accuracy and resolution of DEMs translate into uncertainties in estimates of tsunami inundation zones. The results showed that simply using the 'best available' elevation data, such as the freely available global SRTM elevation model, without considering data accuracy can lead to dangerously misleading results.

Australian Landscapes are prone to fire, from the Northern Savanna to the southern forests of Tasmania. Although fire is natural and is a vital management tool, fires are also a hazard to people and assets across Australia. Sentinel is a national fire hotspots detection and mapping system operated by Geoscience Australia. Sentinel was developed collaboratively by Geoscience Australia and CSIRO and has been operating since 2003. Hotspots are detected using satellite-based sensors monitoring all of Australia up to four times each day. The information is freely available to end-users through a web-site, as data feeds and down-loads. Sentinel has detected over 4 million hot-spots so far. In 2014 Geoscience Australia re-developed Sentinel including: - A more robust and maintainable 'backend' system, enabling quick and easy ingestion of new sources of hotspot data and fire related products - Improved user interface for the visualization of current hotspots and download of archived hotspots data - Separate access for emergency management users to ensure reliable access to hotspots data during major events - Improved interoperability, through reconsideration of the attributes used to describe a hotspot, anticipating the need for a standard approach to this problem