ACRES Update Monitoring pastures from space Remote sensing research at Coleambally Irrigation Area Satellite imagery helps to classify Australia's estuaries

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

Product no longer exists, please refer to GeoCat #30413 for the data

The global downturn in mineral exploration continued in 2001 as planned world-wide expenditure fell to US$2.2 billion from US$2.6 billion in 2000. Australia is the world's leading exploration destination with 17.5% of world mineral exploration budgets. Mineral exploration in Australia in 2000-01 totalled $683.3 million, the first increase (in current dollars) in exploration spending since 1996-97. Western Australia was the leading state for exploration with $424.1 million spent. Gold was the major commodity targeted accounting for 54% of all exploration spending. Access to government-generated geoscientific data and information was improved with the development of the Australian geoscience web portal - <a href="http://www.geoscience.gov.au." target="_blank">www.geoscience.gov.au</a>. Minotaur Resources Ltd reported significant copper-gold-uranium intersections from the Mt Woods Joint Venture, South Australia. Acclaim Exploration NL reported a nickel oxide intersection of 144 m at 1.4% Ni from Wingellina in the Giles Complex, Western Australia. Sipa Resources International NL reported high grade gold intersections at the Waugh prospect, Western Australia, including 15 m at 57.2 g/t Au from 21 m including 3 m at 233 g/t Au from 22 m. Newcrest Mining Ltd further enhanced its Cadia, New South Wales, operation with the first resource estimate of 200 million tonnes at 1.1 g/t Au and 0.41% Cu at the Cadia Far East deposit. Major advances were made in both exploration and project development at the mineral sands projects in the Murray Basin in New South Wales, Victoria and South Australia. Development decisions or commitments to proceed with mine development were made for gold, nickel, mineral sands, diamonds, tantalum and magnesite prospects.

As part of the National Geoscience Agreement with the Northern Territory Geological Survey, Geoscience Australia is evaluating the geological setting of the mafic-ultramafic intrusions in the Arunta Province. The major aims of this study are to constrain the various mafic-ultramafic magmatic systems within the event chronology of the Arunta, and to provide a geoscientific framework for assessing the resource potential of the intrusions. SHRIMP U-Pb geochronology results of thirteen mafic-ultramafic bodies have highligted the episodic emplacement of the Arunta intrusions during the Proterozoic. Five major magmatic events from 1810 Ma to 1130 Ma have been identified. Geochemical discrimination diagrams show that the Arunta intrusions fall into two major geochemical groups that highlight geographical differences in prospectivity for Ni-Cu and platinum-group element mineralisation.

Existing age constraints for geological events in the Tanami Block come predominantly from U-Pb geochronology of i) detrital zircons in sediments, and ii) magmatic zircons in granitoids. These constraints have been used together with observed and inferred geological relationships to help constrain timing of stratigraphy, magmatism, deformation, metamorphism and Aumineralisation (e.g. Vandenburg et al., 2001). Ongoing GA/NTGS zircon geochronology is continuing to refine our understanding of the stratigraphy and magmatic history of the Tanami, with attendant implications for tectonic evolution. In this regard it is noteworthy that detrital zircon ages of ~1815 Ma from the Killi Killi formation require either (or both) a revision of existing stratigraphy, or that the so-called Tanami Orogenic Event significantly post-dates ~1815 Ma, in contrast to previous estimates of ~1845 - 1830 Ma. However, detrital and magmatic zircons can provide no direct constraints on timing of deformation, metamorphism and Au-mineralisation, and consequently our current understanding of these processes in the Tanami region is relatively poor, despite being critical to predictive exploration models.

In 1998, Franklin Cruise FR11/98 recovered 18 dredge hauls in deep water in the Gippsland Basin. The dredge hauls were sited on the basis of seismic reflection profiles and morphological features. The study provided information on the lithologies, ages and paleo-environments of the little-known deepwater Gippsland Basin. The rocks and sediments fall broadly into four categories: volcanics of probable Late Cretaceous age, volcaniclastics and labile sediments of Late Cretaceous age, Neogene marly calcareous sediments, and calcareous oozes of the Quaternary to Holocene. Minor ferromanganese nodules and crusts from several deepwater stations are of no economic potential, being high in SiO2 and remarkably low in copper and cobalt. Volcanics were confined to the three easternmost dredges (present water depths 3300-3800 m) from a rifted block elongated west-northwest and just inboard of the continent-ocean boundary. They consist of basalt, hyaloclastite, breccia, scoria and volcaniclastic sandstone. Because, these volcanic rocks occur on an isolated ridge they cannot have derived pebbles and clasts from younger sequences. The rocks are not dated but may have been laid down during the Tasman Sea rifting phase in the Turonian to Coniacian. We hypothesise that lava flows and domes formed on a coastal plain and in shallow water. Normal vesicular flows formed on dry land, and some weathered to scorias. In water they broke up to form volcaniclastic mass flow deposits such as hyaloclastites. Some of the volcaniclastics apparently became intermingled with soft clays and lime muds, because the interstices are now filled with zeolites, clay minerals and calcite. No Early Cretaceous rocks (Strzelecki Group) age were recovered, suggesting that they were not deposited east of the Gippsland Rise (~149?30?E). Immature labile rocks of the Late Cretaceous (Emperor and Golden Beach Subgroups of the Latrobe Group) were recovered in eleven dredges on the outer continental margin (present water depths 800-2040m). Palynological ages are Turonian to Campanian (~90 Ma to ~74 Ma). Thin to medium bedded labile sandstone, siltstone and mudstone (and their weathered variants) are carbonaceous in part. Some beds are burrowed and mottled or contain cross-lamination, ferruginous nodules, trace fossils, load casts, ripple marks and plants. Marine macrofossils are generally absent. These rocks were apparently deposited rapidly in coastal and marine environments, in the rift involving eastern Australia, Lord Howe Rise, and the Gippsland Basin. Palynology documents the onset on marine conditions, and rapid subsidence between ~90 Ma and ~86 Ma, as the Tasman Sea entered. Silts and clays were deposited in a deep freshwater lake in the Early to mid Turonian, deep marine carbonates in the Santonian, and deep marine muds in the Campanian. Marine calcareous rocks of the post-Eocene Seaspray Group were recovered in eight dredges (present water depths 680-2800 m): medium to very fine grained calcarenites, calcisiltites and calcareous mudstones, composed largely of molluscan debris, foraminifers and clay. They are often poorly bedded, with some thin to medium bedding. Quartz, feldspar, clay clasts and muscovite are common. Mottling shows that bioturbation was widespread, and organic debris includes wood and leaves, sponge spicules and echinoderm spines. Foraminifera date the older rocks as early to middle Miocene. Microplankton indicate deep-water deposition.

This record represents a summary of the specifications of most surveys held in the National Airborne Geophysic Database (updated from 2001 when the fifth edition of this record was released).