Faults of the Lapstone Structural Complex (LSC) underlie 100 km, and perhaps as much as 160 km, of the eastern range front of the Blue Mountains, west of Sydney. More than a dozen major faults and monoclinal flexures have been mapped along its extent. The Lapstone Monocline is the most prominent of the flexures, and accounts for more than three quarters of the deformation across the complex at its northern end. Opinion varies as to whether recent tectonism, or erosional exhumation of a pre-existing structure, better accounts for the deeply dissected Blue Mountains plateau that we see today. Geomorphic features such as the abandoned meanders at Thirlmere Lakes illustrate the antiquity of the landscape and favour an erosional exhumation model. According to this model, over-steepened reaches developed in easterly flowing streams at the Lapstone Monocline when down-cutting through shale reached more resistant sandstone on the western side of the LSC. These over-steepened reaches drove headward (westerly) knick point retreat, ultimately dissecting the plateau. However, a series of swamps and lakes occurring where small easterly flowing streams cross the westernmost faults of the LSC, coupled with over-steepened reaches 'pinned' to the fault zones in nearby larger streams, imply that tectonism plays a continuing role in the development of this landscape. We present preliminary results from an ongoing investigation of Mountain Lagoon, a small fault-bound basin bordering the Kurrajong Fault in the northern part of the LSC.

The Kangaroo Caves zinc-copper deposit in the Archaean Panorama District in the northern Pilbara Craton, Western Australia contains an Indicated and Inferred Mineral Resource of 6.3 million tonnes at 3.3% zinc and 0.5% copper. The Kangaroo Caves area is characterised by predominantly tholeiitic volcanic rocks of the Kangaroo Caves Formation, which is overlain by turbiditic sedimentary and volcanic rocks of the Soanesville Group. Zinc-copper mineralisation is hosted mainly by the regionally extensive Marker Chert, the uppermost unit of the Kangaroo Caves Formation, and structurally controlled by D1 synvolcanic faults. The upper area of the deposit is characterised by quartz-sphalerite ± pyrite ± baryte ± chalcopyrite, whereas the lower area contains mainly chlorite-pyrite-quartz-carbonate-sericite ± chalcopyrite ± sphalerite. Laser ablation inductively coupled plasma mass spectrometry analyses show that cobalt-nickel ratios in pyrite are significantly greater in the upper, zinc-rich area (median copper/nickel = 0.4) of the deposit than the lower, zinc-poor area (median copper/nickel = 5). Structural analysis of the Kangaroo Caves area combined with Leapfrog modelling of ore and trace element distribution shows that the deposit is predominantly an elongate sheet of zinc mineralisation (-1%), which plunges ~30° to the northeast and is approximately 1000 metres in length. The morphology of the Kangaroo Caves deposit was retained from its original formation, despite rotation during the D2 event. Variations in hydrothermal alteration assemblages, including the copper and nickel contents of pyrite within the deposit and underlying dacite, are interpreted to be the result of variations in the influx and mixing of seawater with upwelling volcanogenic fluids during zinc-copper mineralization. At the Kangaroo Caves area the cobalt-nickel ratio of pyrite can be used as an exploration vector towards high-grade zinc-copper mineralization.

We analyse 11 years data from nine continuous GPS receivers distributed over Antarctica to determine vertical crustal motion. The vertical velocities determined by GPS in the latest reference frame IGS05 (a realization of the reference frame ITRF2005) are transformed to the reference frame CE2007 (Argus 2007 GJI) as the centre of mass of the Earth is constrained poorly by SLR in ITRF2005. Uncertainties of the vertical velocities are estimated using combined white and flicker models. Two GPS stations O'Higgins and Palmer in the north Antarctic Peninsula, show uplifts of +6.7 2.4 mm/yr and +5.4 1.7 mm/yr respectively. GPS station Vesleskarvet in Queen Maud Land shows uplift of +1.7 0.8 mm/yr. Recent GRACE research shows ice loss rates of -28.8 7.9 km /yr in the north Antarctic Peninsula and -16.7 9.7 km /yr in Queen Maud Land. The GPS station Casey shows uplift of +1.3 0.7 mm/yr where some ice loss is also indicated by GRACE data. Therefore, the signs of the results from GPS are consistent with the signs of results from GRACE. On the other hand, subsidence of -0.7 0.4 mm/yr is detected at GPS stations Mawson and Davis in East Antarctica where a mass accumulation rate of +21 11 km /yr has been detected by GRACE data. The signs of these results from GPS and GRACE are also consistent. In addition, no significant vertical crustal changes have been detected at GPS stations Dumont d'Urville and McMurdo where no significant mass changes have been detected from GRACE data. We conclude that our GPS analysis results can detect crustal vertical motion very accurately and the signs of GPS results are consistent with the signs of mass changes in Antarctica detected by GRACE.

A deep seismic reflection profile and coincident refraction and magnetotelluric data were acquired across the northern Eyre Peninsula, Gawler Craton in 2008 to enhance the prospectivity of the Gawler Craton for uranium and geothermal energy, by establishing the regional geodynamic framework and improving our understanding of the crustal architecture. The seismic line crossed the western boundary of a region of elevated surface heat flow, termed the South Australian Heat Flow Anomaly (SAHFA). This broad zone correlates with elevated surface heat production values, predominantly associated with high heat producing granites, and thus the boundary is an isotopic and geochemical boundary. The seismic line crosses several tectonic domain boundaries in the Gawler Craton, including between the Archaean core of the craton and younger domains to the east and west. It also crossed the Kalinjala Shear Zone, which is a key structure in the southern and central Gawler Craton, defining a boundary between Hutchison Group sedimentary rocks and Donington Suite granites in the south. In the vicinity of the seismic section, this shear zone dips moderately to the east and appears to be a major crustal-scale fault which cuts through to the Moho; it separates mid to lower crust of differing seismic reflectivity, with strong reflectivity west of the fault, and a lower reflectivity to the east. The upper crust appears to be dominated by a series of thin-skinned thrust faults, most of which dip to the east. The seismic line also crossed the boundary between the Olympic Fe-oxide Cu-Au-U Province (host of Olympic Dam and Prominent Hill deposits) in the east, and the Central Gawler Au Province in the west, and tested the difference in crustal architecture between the two mineral provinces.

Abstract: Compressional deformation is a common phase in the post-rift evolution of passive margins and rift systems. The central-west Western Australian margin, between Geraldton and Karratha, provides an excellent example of a strain gradient between inverting passive margin crust and adjacent continental crust. The distribution of contemporary seismicity in the region indicates a concentration of strain release within the Phanerozoic basins which diminishes eastward into the cratons. While few data exist to quantify uplift or slip rates, this gradient can be qualitatively demonstrated by tectonic landforms which indicate that the last century or so of seismicity is representative of patterns of Neogene and younger deformation. Pleistocene marine terraces on the western side of Cape Range indicate uplift rates of several tens of metres per million years, with similar deformation resulting in sub-aerial emergence of Miocene strata on Barrow Island and elsewhere. Northeast of Kalbarri near the eastern margin of the southern Carnarvon Basin, marine strandlines are displaced by a few tens of metres. A possible Pliocene age would indicate that uplift rates are an order of magnitude lower than further west. Relief production rates in the western Yilgarn Craton are lower still - numerous scarps (e.g. Mount Narryer) appear to relate individually to <10 m of displacement across Neogene strata. Quantitative analysis of time-averaged deformation preserved in the aforementioned landforms, including study of scarp length as a proxy for earthquake magnitude, has the potential to provide useful constraints on seismic hazard assessments in a region containing major population centres and nationally significant infrastructure.

This is a combined metamorphic and strain map of the Eastern Yilgarn Craton. Inset maps of different phases of metamorphism are also shown. <p>Related material<a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&catno=68806">Metamorphic Evolution and Integrated Terrane Analysis of the Eastern Yilgarn Craton: Rationale, Methods, Outcomes and Interpretation</a> - Geoscience Australia Record 2009/023.</p>

This web service provides access to the Geoscience Australia (GA) ISOTOPE database containing compiled age and isotopic data from a range of published and unpublished (GA and non-GA) sources. The web service includes point layers (WFS, WMS, WMTS) with age and isotopic attribute information from the ISOTOPE database, and raster layers (WMS, WMTS, WCS) comprising the Isotopic Atlas grids which are interpolations of the point located age and isotope data in the ISOTOPE database.

This web service provides access to the Geoscience Australia (GA) ISOTOPE database containing compiled age and isotopic data from a range of published and unpublished (GA and non-GA) sources. The web service includes point layers (WFS, WMS, WMTS) with age and isotopic attribute information from the ISOTOPE database, and raster layers (WMS, WMTS, WCS) comprising the Isotopic Atlas grids which are interpolations of the point located age and isotope data in the ISOTOPE database.

Neotectonic faulting and uplift has previously been described from field evidence in higher relief erosional areas in far northwest NSW. In this study, airborne electromagnetics (AEM) and high resolution LiDAR datasets were used to identify buried neotectonic features in the Lower Darling Floodplain and adjacent lowlands. The AEM data (acquired over an area of 7,500 sq km and validated by 100 new boreholes) reveal that the top surface of the ?Late Pliocene to Pleistocene Blanchetown Clay, a widespread lacustrine fine grained unit deposited in palaeo Lake Bungunnia, has an undulating to sharply offset surface. Gridding of closely spaced points on AEM flight line sections suggests that it has been affected by local warping and faulting, as well as regional tilting due to basin subsidence or margin uplift. Local relief reaches 20m, with small highs and lows apparently controlled by networks of closely spaced intersecting faults that are mostly expressed as warps in the near surface. Across the entire area, the top of the Blanchetown Clay varies in elevation from 20 to 80 m AHD. Some of the up-warped areas are associated with local landscape highs, but most structures have no apparent surface expression. However, the Darling River and its anabranches (Talyawalka, Charlie Stones and Tandou Creeks, and the Great Darling Anabranch) follow zones of local structural lows, and some of the interpreted faults are echoed by linear river reaches and terrace edges interpreted from LiDAR DEM and satellite imagery. Geomorphic mapping and dating of scroll-bar sediments suggest that the main course of flow of the Darling River system has previously flipped between two preferred courses (the modern Darling, and a course following Talyawalka Creek/Tandou Creek/Redbank Creek/Great Darling Anabranch). This newly discovered structural control explains why the Lower Darling channel has apparently not migrated across the entire floodplain.

Ongoing developments in geodetic positioning towards greater accuracies with lower latency are now allowing the measurement of the dynamics of the Earth's crust in near real time. However, in the Australian circumstance a sparsity of geodetic infrastructure has limited the application of modern, geodetic science to broader geoscience research programs. Recent enhancements to the Australian geodetic infrastructure, through the AuScope initiative, offer opportunities for research into refinement of geodetic accuracies, as well as their application to measuring crustal deformation.