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.

Overall, the cruise met its objectives of studying rift and drift sedimentation, and obtaining cores for palaeo-oceanography. The east Tasmanian seismic program was completely successful. The planned sampling program was somewhat curtailed by bad weather, equipment failures and other factors. It was least successful off east Tasmania. A total of about 1300 km of 8-fold multichannel seismic data were acquired along 8 transects across the east Tasmanian margin. The quality of the seismic profiles was excellent, with good resolution and penetration, given the bad weather and the limitations of the acquisition system. The seismic source comprised 2 GI airguns (each 45/105 cu. in. capacity) giving a penetration of 2-2.5 s twt (2.5-3 km) in places. The seismic profiles indicate a structurally complex margin with rugged basement relief that includes large-scale horst/graben structures and volcanic intrusions. The sedimentary section on the continental slope is at least 1.5 s twt thick in some graben and includes Campanian-Paleocene early sag-phase deposits, which are 0.5-1.0 s twt thick. Regional compressive tectonism in the Late Paleocene-Early Eocene has produced widespread inversion (folding/faulting) in this succession. A wedge of Neogene shallow-water carbonates underlies the continental shelf. It shows seaward progradation and attains a maximum thickness of ~700 m beneath the shelf edge. Oceanic basement (?Campanian) adjacent to the margin lies at a depth of 7.0-7.5 s twt. The continental rise and Tasman Abyssal Plain in this zone are underlain by 1.5-2.0 s twt of post-breakup sedimentary section. The East Tasman Saddle is underlain by `transitional? basement and contains a sedimentary section of similar thickness. During the sampling program 58 of 86 stations were successful: 38 gravity cores (21 successful), 4 piston cores (3), 16 dredges (7) and 28 grabs (28). Total core recovery was 81.4 metres from the 16 successful cores taken in soft sediments, an average recovery of about 5 metres. The fairly low success rate with the gravity corer can be ascribed to problems with foram sand east of Tasmania, and shelly sand in Storm Bay. The low success rate with the dredge was related to the lightness of the gear. The deployment of the heavy piston corer for the first time on Franklin was successful. However, we did not attempt to piston core in deep water. East of Tasmania we recovered 8 gravity cores, and 7 dredge hauls. Deepwater dredging and coring were surprisingly unsuccessful. The upper slope stations, designed to sample older rocks, were reasonably successful. From these results and some existing information, general conclusions can be drawn about changes along the margin with increasing water depth. The shelf and upper slope wedge of Neogene, seaward-prograding sediments was sampled out to 1640 m. The sediments recovered include muddy sand, clayey sandstone with siliceous nodules, siliceous sandstone and calcarenite. The calcarenite is presumably part of the Middle Miocene shelf limestone sequence that is widespread off St Helens. Somewhat deeper on the upper slope, basement outcrops occur in steep slopes: granite, arkose, metasediments, conglomerate, quartz sandstone and gritty mudstone. The granites are probably from Devonian batholiths like those onshore up the east coast. Volcanic rocks and conglomerate form a basement block in deeper water on a ridge off northeast Tasmania at ~3750m. Deepwater outcrop ridges support manganese nodules and crusts. Nannofossil oozes cling to the slope, particularly in local basins, and are ubiquitous in deep water. The East Australian Current apparently winnows many of the oozes to form a blanket of foram sand.

Current geological mapping by the Northern Territory Geological Survey is leading to a much better understanding of the surface geology of the Territory. Less well understood is the geometry of the Northern Territory in the third dimension, although this has been predicted by the construction of cross sections (e.g. on recent 1:250 000 geological maps). At shallow depths, the cross sections can be constrained by drilling results, if available, but deeper levels can only be examined by geophysical techniques such as seismic reflection or magnetotelluric profiling, or by modelling of potential field data. Text of paper presented at the NTGS AGES 2002 Workshop, Alice Springs, 26-27 March 2002.

This data set was compiled to provide geological context for the 2001 seismic reflection line acquired between Leonora and the northwest of the Neale 1:250 000 sheet. The data set includes reviewed solid geology for the Leonora (Blewett) and Laverton (Whitaker) 1:250 000 sheets but also includes 1:100 000 sheets for northeast Menzies and northern Edjudina 1:250 000 sheet areas as well as aeromagnetic interpretation of the Rason and Neale 1:250 000 sheets. Archaean rocks of the Eastern Goldfields Province of the Yilgarn Craton form basement to the area traversed in the seismic survey. In the west, granite and abundant greenstone of the Norseman-Wiluna Belt are dislocated by major north-northwest to north oriented shear zones. East of the Norseman-Wiluna Belt, the crust is dominated by granitic lithologies with shear zones and greenstone in much lower abundance. Gneiss of the Proterozoic Albany-Fraser Province abuts the Yilgarn Craton about 50 km to the east of the eastern end of the seismic line.

In addition to the devastating 1989 Newcastle earthquake, at least four other earthquakes of magnitude 5 or greater have occurred in the surrounding Hunter region since European settlement in 1804. Some of these earthquakes caused damage in areas that, at the time, were sparsely populated. Similar events, were they to occur today in populated areas, would certainly cause significant damage. The frequency with which these events have occurred in the Hunter region suggests that earthquakes pose a genuine threat to the communities there. This study presents the most comprehensive and advanced earthquake risk assessment undertaken for any Australian city to date. It has focused on the economic losses caused by damage to buildings from earthquake ground shaking, and not on the impacts from other, secondary hazards such as soil liquefaction and surface faulting. The study has adopted a probabilistic approach that makes allowances for the variability that is inherent in natural processes as well as the uncertainty in our knowledge. The results from this project will assist decision-makers involved in local and state government, policy development, the insurance industry, engineers, architects, and the building and finance industries to manage potential damage and loss of life from earthquakes in Newcastle and Lake Macquarie. The results also have implications for the earthquake risk facing larger Australian cities such as Sydney, Melbourne and Adelaide. This is due to a number of factors, including similarities between the earthquake hazard in Newcastle and Lake Macquarie and other parts of Australia, and similarities between the urban environments, particularly the composition of the building stock.

Proceedings of papers presented at an industry workshop held in Perth, 20 June 2002. Edited by K.F. Cassidy

Legacy product - no abstract available

The Archaean granite-greenstones in the SIR SAMUEL 1:250 000 sheet area can be divided into three north- to north-northwest-trending strips of greenstones that are separated by large areas of granitoid. The west strip varies in width from 2 to 17 km, and includes the Perseverance-Mount Keith, Agnew, and Yakabindie greenstone belts. The far west part of the sheet is largely granitoid, with an arcuate belt up to 18 km wide of highly deformed and gneissic granitoid west of the Waroonga Shear Zone. The southern Yandal greenstone belt is separated from the Perseverance-Mount Keith greenstone belt by a large area of granitoid, including the sigmoidal Koonoonooka monzogranite, and a highly deformed zone, up to 12 km wide, of interleaved granitoid and greenstone west of the Mount McClure Fault. Part of the Dingo Range greenstone belt occurs in the northeast. The Yakabindie greenstone belt comprises a layered sequence of the Kathleen Valley Gabbro overlain by the massive tholeiitic Mount Goode Basalt. The Agnew greenstone belt comprises a lower sequence of metamorphosed ultramafic, mafic, felsic volcanic, and sedimentary rocks, which is exposed in the Lawlers and Leinster Anticlines. The upper sequence, as in the Mount White Syncline area, consists of metabasalt, metagabbro and metasedimentary rocks. Metamorphosed ultramafic, mafic, felsic volcanic and sedimentary rocks in the Perseverance area extend farther north to west of Mount Pasco. From Six Mile Well, ultramafic, sedimentary, and felsic volcanic/volcaniclastic rocks correlate well with the greenstone sequences through Mount Keith to Wiluna. The Jones Creek Conglomerate represents a late clastic sequence and is restricted to a narrow, fault-bounded zone between the Yakabindie greenstone belt and granite in the west and the Perseverance-Mount Keith and Agnew greenstone belts to the east. The southern Yandal greenstone belt consists of two major packages of greenstones, i.e., mafic and som e ultramafic rocks in the Bronzewing - Mount McClure, Hartwell, Yandal Well and Darlot areas, and felsic rocks along the Ockerburry Fault Zone and Spring Well area. In the Dingo Range greenstone belt, the Dingo Range antiform is interpreted to be a refolded earlier fold of banded iron formation/chert, ultramafic and basaltic rocks. In the Mount Harold area some felsic volcanic/volcaniclastic rocks occur. The Stirling Peaks area is largely little deformed fine grained metabasalt. Three major deformation events are recognised in the granite-greenstones in the SIR SAMUEL area. The first deformation, although poorly understood, produced bedding-parallel foliation including flattened pillow structures in basalt, and some tight to isoclinal folds. Major orogenic compression during D2 produced the north-northwest greenstone belt trends and linear structures including faults, shear zone s and folds. During D3, deformation appears to have been largely concentrated along major shear zones. Some north- to north-northeast-trending structures were probably produced, or reoriented into their current positions, during D3, which shaped the current structural architecture. Structures in the southern Yandal greenstone belt are best configured in terms of a compressional jog. Post-D3 deformation is represented by normal faults, fractures, and sub-horizontal crenulations. A major phase of regional metamorphism was initiated during D2 and peaked late during or after D2. Granite intrusion occurred throughout the deformation and metamorphic history in the SIR SAMUEL area. Related products <a href="https://www.ga.gov.au/products/servlet/controller?event=GEOCAT_DETAILS&amp;catno=34433">Associated 1:250,000 scale digital dataset product information</a>

In 2001, Australia's economic demonstrated resources (EDR) of bauxite, copper, gold, lead, magnesite, ilmenite, zircon, nickel, phosphate, PGM, tantalum, silver, vanadium and zinc increased, while those of black coal, diamonds, iron ore, lithium, manganese ore and uranium decreased. EDR of brown coal was maintained at levels similar to those reported in 2000. The reductions in EDR were due mainly to ongoing high levels of production; with low commodity prices a subsidiary factor. EDR of gold, nickel and mineral sands reached record levels. Gold EDR rose by 4% and was over 80% of total demonstrated resources, this increase in resources continuing the established long-term growth trend for gold. In recent years that trend has continued despite falling exploration expenditure reflecting an increasing trend to concentrate exploration efforts in brownfields regions in response to the sustained period of depressed gold price. Australia, continues to rank as one of the world's leading mineral resource nations. It has the world's largest EDR of lead, mineral sands, nickel, silver, tantalum, uranium and zinc. In addition, its EDR is in the top six worldwide for bauxite, black coal, brown coal, cobalt, copper, gold, iron ore, lithium, manganese ore, rare earth oxides and gem/near gem diamond. Mineral exploration expenditure rose by 1% to $683.3 million in 2000-01, which was the first increase in annual exploration spending since 1996-97. However spending for calendar year 2001, based on the sum of ABS four-quarter figures, was down by $12 million to $664.4 million. Production of many mineral commodities again reached record levels in 2000-01, and overall mine production is projected by ABARE to rise in the five years to 2006-07 with the exception of gold which they forecast will fall by 6%. ABARE have projected a very high growth of some 60% for mine production of nickel in this period. Increases are also forecast for mine production of coal (+17%), copper (4%), lead (3%), zinc (12%), bauxite (17%) and iron ore (19%).

Linespacing for the survey is 150 metres