Over the last fifteen years, Geoscience Australia, through its Onshore Energy Security Program, in conjunction with Primary Industries and Resources South Australia (PIRSA), the Geological Survey of New South Wales (Industry & Investment NSW), the Australian Geodynamics Cooperative Research Centre, and the Predictive Mineral Discovery Cooperative Research Centre (pmd*CRC), has acquired several deep seismic reflection profiles, which, when combined, form an east-west transect about 870 km long in southeastern Australia. The seismic data vary from low-fold, dynamite-source to higher-fold, vibroseis-source data. The combined seismic profiles, from the western Eyre Peninsula to the Darling Basin, provide a near complete cross-section of the crust across the Gawler Craton, Adelaide Rift System, Curnamona Province, Koonenberry Belt and Darling Basin. The entire region is dominated by east-dipping faults, some of which originated as basin-bounding extensional faults, but most appear also to have a thrust sense of movement overprinting the extension. In the Gawler Craton, an inferred shallow, thin-skinned thrust belt occurs to the west of an inferred thick-skinned thrust belt. The boundary between the two thrust belts, the Kalinjala Mylonite Zone, was active at least during the Kimban Orogeny, with possible extensional movement at that time. The thrust movement possibly occurred during the ~1600 Ma Olarian Orogeny.

Developed in consultation with Emergency Management Australia (EMA), this kit defines and maps major hazards affecting Australia - earthquakes, tsunamis, landslides, volcanoes, severe storms, cyclones, bushfires, floods and droughts. This kit helps students and teachers recognise risks from different natural hazards and the practical steps we can all take to reduce their effects. The Australian Natural Hazards Education Map Kit contains: - eight colour A3 poster maps with descriptive text - eight blackline A4 map masters - background information on each hazard - student activities - Emergency Management Australia hazard action cards Suitable for primary years 5-6 and secondary years 7-8.

No abstract available

Modern adakite forms in subduction zones with unusually high geotherms that result in high-pressure melting of subducted basaltic crust. Close geochemical similarities between adakite and Archaean TTG, which forms the major component of Archaean crust, have supported a view that Archaean TTG is likewise subduction related. However, recent studies have shown that conditions of adakite formation are not unique to a subducting slab and can be attained in basaltic lower crust in both subduction and non-subduction environments. Non-subduction environments may be equally relevant to the genesis of Archaean TTG. Heat flow calculations suggest that Archaean subduction (if it occurred), must have been at a low angle ? the same style of subduction that produces most modern adakites. However, if Archaean TTG was derived from a subducting slab, then like most modern adakites, it should show 1) evidence for interaction with a mantle wedge, and 2) an association with diagnostic subduction influenced magmas such as high-Mg andesite (sanukitoid), Nb-enriched basalts and boninites. Whereas this does appear to be the case for some Late Archaean terrains (e.g. Superior Province), such is not unequivocally the case for older terrains. This suggests either that Early Archaean TTG is not subduction related, or that the style of Early Archaean subduction was significantly different from modern subduction, including low-angle or flat subduction. The volume of preserved felsic crust in the Early Archaean Pilbara Craton, Western Australia, requires a complimentary volume of dense mafic material (residual after basalt melting) equaling a combined thickness of ~170 km, which is difficult to conceptualize through solely magmatic processes (e.g. underplating, mantle plume). Subduction provides a means whereby large volumes of mafic crust can be progressively cycled through a melting zone, but if applicable to the Early Archaean, features such as typically low Mg#, Cr, and Ni indicate that TTG melts of that crust must have avoided interaction with the mantle. We suggest that Early Archaean slabs were pushed or thrust beneath overriding basaltic crust, without the development of a mantle wedge. Early Archaean TTGs are melts of the underthrusted slab and their petrogenesis combines components of the subduction model for modern adakite and models for lower crustal sodic melts (e.g. Cordillera Blanca ? Peru; Ningzhen ? China).

This Australian volcanoes image set comprises 15 images on CD-ROM with accompanying descriptive text and student question/s for each image. Learn the history of Australia's hot spot volcanoes over 60 million years and examine 9 Australian volcanoes in detail. Suitable for primary levels Years 5-6 and secondary levels Years 7-10

Subduction of oceanic crust at an unusually low angle (flat-subduction) has been proposed as a general model for the growth of continental crust older than about 2.5 Ga. At modern zones of flat subduction, magmatic additions to new crust come from partial melting of both the subducting oceanic crust (slab) and the thin wedge of mantle above the slab. Evidence for both a slab and wedge source is commonly preserved in some, but not all, late Archaean (3.0-2.5 Ga) terrains, but we find little evidence that a mantle wedge contributed to early Archaean (>3.0 Ga) crustal growth. In contrast to most modern terrains and some late-Archaean terrains, early Archaean continental crust evolved through direct melting of thick mafic crust.

Aspects of the tectonic event history of Palaeo- to Mesoproterozoic Australia are recorded by metasedimentary basins in the Mt Isa, Etheridge, and Coen Provinces in northern Australia and in the Curnamona Province of southern Australia. Based on similarities in depositional ages and stratigrapy, these basins are interpreted to have been deposited in a tectonically-linked basin system. However, in deformed and metamorphosed basins, field correlations are difficult, making independent data, such as Nd isotope data and detrital zircon U-Pb geochronology essential to discriminate tectonic setting and sediment provenance.

4 reproducible student activities suggested answers Suitable for primary levels Year 6 and secondary level Years 7-8

A database of 1075 high-precision geochemical analyses of ultramafic-mafic units, predominantly flows, was compiled for the Eastern Yilgarn Craton. Samples are divided into a high-Mg population at MgO-10-24 wt.% and a basaltic population where 4-MgO<10 wt.%. There are 8 groups based on (La/Sm)N and Nb/Th ratios. Four magma series are identified. Uncontaminated komatiitic-basalts have MgO ~ 11-23 wt.% and Nb/Th-8, whereas contaminated counterparts have Nb/Th<8 corresponding to siliceous high-Mg basalts (SHMB). A distinct magma series with MgO ~ 5-18 wt.% MgO has a narrow range of Nb/Th at 0.5-?2 over a range of (La/Sm)N from 0.7-5.5, unlike contaminated suites where (La/Sm)N and Nb/Th are correlated; this series corresponds to the enriched-Paringa basalt of the Kalgoorlie Terrane. A third high-Mg magma series has a narrow range of MgO at ~13-16 wt.%, extends to elevated TiO2 and Ni relative to komatiitic-basalts at that MgO range, and features (La/Sm)N ?2. Prevalent, crustally uncontaminated, tholeiitic basalts all have Nb/Th?8, span Mg-rich to fractionated Fe-rich counterparts, and range from LREE-depleted to mildly LREE enriched. Contaminated equivalents have Nb/Th<8. Two additional uncontaminated tholeiitic basaltic groups are defined respectively by high-Nb to 20 ppm akin to alkaline ocean island basalts, and elevated total-REE relative to the other basaltic groups. Contamination of all groups was dominantly by interaction with continental mantle lithosphere with a minor crustal component.

Explore important concepts about plate tectonics using this comprehensive teaching resource. Includes sections on the Earth's layers, plate boundaries, theory of plate tectonics, supercontinents and Australia's tectonic history. This 109 page colour booklet is suitable for use by Year 6-12 Science teachers or high school students. Student activities include suggested answers.