AndreaBozzo/ceres-open-data-index huggingface dataset:
A non-marine Lower Cretaceous rift-related epicIastic volcanic unit in southern Australia: the Eumeralla Formation in the Otway Basin.  Part II: fluvial systems

Relationships, thicknesses, and palaeocurrent and other sedimentary data applying to facies associations in Eumeralla Formation outcrops in the eastern Otway Basin distinguish at least three discrete depositional systems (A-C). Each system is characterised by high-energy fluvial flows in broad channel tracts.  The multistorey sandstone bodies of system A, between Cape Otway and Apollo Bay, are up to 70 m thick and contain varying proportions of basement-derived quartzose gravel and sand intermixed with mainly volcaniclastic sand.  Interchannel siltstones also up to 70 m thick separate the sandstone bodies.  Palaeocurrents in system A have an overall southerly trend.  This system is interpreted to represent deposition in a medial alluvial fan to proximal braided-stream system.  System B occurs around Moonlight Head, and may extend southeast to Rotten Point.  It is characterised by multistorey sandstone bodies up to 14 m thick separated by siltstones of similar thickness which locally contain thin coal beds, rooted horizons, and reddened soil profiles.  It lacks basement-derived gravel. Palaeocurrents trend north-easterly to northwesterly. The sediments of system B accumulated on a medial to distal braid plain.  Facies associations and fluvial architecture of system C, seen in outcrop north of Skenes Creek, resemble those of system B, from which it is distinguished by consistently northwest palaeocurrent vectors, a basement-derived gravel component, and the absence of debris flows and volcanic pebbles. System C also represents deposition on a braid plain or in a braided-river system.  The three depositional systems are accommodated in a model for the Eumeralla Formation which suggests that its volcanic detritus was derived largely from infrarift volcanic complexes in the axial parts of the Otway rift basin, which during the Aptian-Albian lay to the south of the present coastline.  A volcaniclastic apron spread northwest to northeast across the basin (system B).  Elevated basement blocks shed quartzose detritus into flanking alluvial fans, the more distal parts of which mixed with volcaniclastic detritus (systems A, C).  The onset of axial volcanism in the Aptian may have displaced a former westerly axial drainage towards the northern basin margin (system C).

Tags: Earth Sciences, GA Publication, Journal, NSW, Published_External, SA, TAS, VIC, WA
Organization: Geoscience Australia Data
Capel and Faust Basins - New Information from the Offshore Frontier Between Australia, New Zealand and New Caledonia

New geophysical and geological datasets have been acquired in water depths of 1300-2500m from the Capel and Faust basins located some 800 km east of Brisbane (Figure 1). Between December 2006 and January 2007 Geoscience Australia acquired ~6000 km of industry standard 2D seismic data using an 8 km solid streamer.  The survey identified numerous depocentres, some up to 150 km in length and 40 km in width with up to 7 km of sediment fill. Initial interpretation has identified a potential pre-rift succession, three syn-rift phases (clastic/volcanic), and two post-rift carbonate packages. Episodes of post-rift igneous activity are also apparent. Possible correlations with the Capricorn, Great South and/or deepwater Taranaki basins are suggested.

In late 2007 the RV Tangaroa completed a marine reconnaissance survey of the Capel and Faust basins. Geophysical datasets acquired on this survey included gravity, magnetics, multibeam sonar, and sub-bottom profiler data. An accompanying seafloor sampling program acquired geological and biological samples from potential seepage sites and representative areas of the sea floor, to search for indications of active petroleum systems and to document marine biodiversity and habitats.  These datasets are designed to better define the region's petroleum prospectivity and inform marine and environmental planning decisions.   

The multibeam sonar revealed seafloor features that appear to reflect the underlying basin structure, such as fault-related slumps. The gravity and magnetic coverages are expected to significantly improve the delineation of depocentre boundaries. Seafloor sampling and camera footages provided information on the substrate composition and potential fluid escape sites. Current work involves the initial interpretation of these datasets and their integration to define the rift basin architecture and tectonostratigraphic history to better understand the region's petroleum prospectivity.

Tags: AU, Earth Sciences, External Publication, NZ, Published_External, marine, petroleum exploration, sedimentary basins, seismics, stratigraphy, structural geology
Organization: Geoscience Australia Data
Complete Bouguer Gravity Anomaly Colour Composite Image of Onshore Australia 2016

This gravity anomaly image has been derived from observations stored in the Australian National Gravity Database (ANGD) as at February 2016 as well as data from the 2013 New South Wales Riverina gravity survey. Out of the approximately 1.8 million gravity observations 1,371,998 gravity stations in the ANGD together with 19,558 stations from the Riverina survey were used to generate this image. The image shows complete Bouguer anomalies over onshore continental Australia. The data used in this image has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. 
Terrain corrections to gravity were calculated using both offshore bathymetry and onshore topography data. These terrain corrections were applied to the spherical cap Bouguer anomalies used in the Bouguer Gravity Anomaly Grid of Onshore Australia 2016 to produce the complete Bouguer anomalies shown in this image.
The Complete Bouguer Gravity Anomaly Grid of Onshore Australia 2016 has been image enhanced and displayed as a hue-saturation-intensity (HSI) image with sun shading from the northeast to create this product.

Tags: Bouguer, Complete Bouguer, Earth Sciences, Gravity Digital Data, HSI, National dataset, Published_External, geophysics, gravity, terrain correction
Organization: Geoscience Australia Data
Kimberley Region and WA Reefs Satellite-Derived Bathymetry Acquisition (20220090C)

The Kimberley Region and WA Reefs Bathymetry was derived by EOMAP form multispectral satellite data from the European Space Agency’s Sentinel-2 satellite sensor. EOMAP was contracted by Geoscience Australia (GA) to provide high-resolution (10m) Satellite-Derived Bathymetry (SDB) for the Priority Australian Seabed Mapping Sites. The survey area encompasses an area within Kimberley Region in Western Australia which includes Ashmore Reef, Browse Island, Cartier Island, Clerke Reef, Cunningham Island, Mermaid Reef, Scott Reef and Seringapatam Reef. These critical geospatial data layers provide the essential environmental baseline information for the long-term monitoring and management of these Marine Parks. Mapping the shallow water zone is of importance both from an environmental and socioeconomic perspective. Having access to digital, georeferenced, high-resolution maps of bathymetry and benthic habitats of shallow water areas, is of fundamental use in the areas of navigation, ecological research, environmental modelling, management and conservation, and monitoring the impacts from climate change. Bathymetry data was processed using the physics-based inversion method to derive quantitative information of the shallow water bathymetry using the reflected sunlight energy in different wavelengths of the visible and near infrared region. A detailed delivery report is provided in: Delivery Report: Satellite-Derived Bathymetry, Priority Australian Seabed Mapping Sites. Reference: 20220304.0888. EOMAP Australia Pty Ltd. This dataset is not to be used for navigational purposes. This dataset is published with the permission of the CEO, Geoscience Australia.

Tags: AusSeabed, EARTH SCIENCES, Earth Science | Oceans | Bathymetry/Seafloor Topography | Bathymetry, HVC_144641, Oceans, Published_External, Satellite-Derived Bathymetry, Sentinel-2, bathymetric grids, bathymetry, satellite-derived bathymetry (SDB)
Organization: Geoscience Australia Data
Spectral representation of isostatic models

The development of cross-spectral techniques for investigating the relation between gravity and topography has led to the representation of isostatic processes in terms of mathematical filters, or admittance functions. These filters can easily be constructed by application of Greens equivalent layer theorem. The rheology of the lithosphere principally controls the process by which isostatic compensation is achieved. As examples, admittance functions representing the isostatic process defined by elastic and visco-elastic rheologies are developed. By using admittance functions, the calculation of the free-air gravity anomaly for complicated topography, isostatic schemes, or rheology becomes computationalIy more efficient and simple compared to the more conventional line-integral methods.

Tags: Earth Sciences, GA Publication, Journal, Published_External, marine
Organization: Geoscience Australia Data
Sources and Sinks of Terrigenous Sediments in the Southern Gulf of Carpentaria Geoscience Australia Survey 238: Post Survey Report

This record contains the preliminary results of Geoscience Australia marine survey 238 (SS04/2003) to southeast Gulf of Carpentaria. The survey was completed between 9 May and 10 June 2003 using Australia's national facility research vessel Southern Surveyor. The survey included Geoscience Australia and CSIRO and Marine and Atmospheric Research scientists.

Tags: AU-NT, AU-QLD, Earth Sciences, GA Publication, Published_External, Record, bathymetry, carbonate, geomorphology, geophysics, marine
Organization: Geoscience Australia Data
New SHRIMP U-Pb ages of basement units from the Carpentaria Lowlands Region, Queensland. NE Queensland Solid Geology Project, 2026

New Sensitive High Resolution Ion Microprobe (SHRIMP) U–Pb geochronological results for three samples are presented in this Record. The samples are from cores of basement units intersected in drill holes that penetrated overlying rocks of the Karumba (Cenozoic) and Carpentaria (Mesozoic) basins. One of the samples is from the Proterozoic Keer Weer Province, one is from the adjoining Proterozoic Kowanyama Province, and the third is from the Carboniferous–Permian Townsville–Mornington Island Belt (Kennedy Igneous Association).

Extensively altered gneiss (sample BB6204/11044786) of the Keer Weer Complex was intersected at a depth of ca 885.7 m in bore hole Z.C.L. Weipa 1 located ca 11 km southeast of Weipa. The gneiss is interpreted to represent a deformed and recrystallised granitoid and is in an area of high magnetisation on geophysical images. Zircons analysed from sample BB6204/11044786 collected from the ca 974.8–976.6 m interval yielded a 207Pb/206Pb magmatic crystallisation age of 1539.7 ± 2.8 Ma.

An almost identical 207Pb/206Pb magmatic crystallisation age of 1538.4 ± 3.3 Ma was obtained for sample BB6200/11044787, a diorite representing the basement in F.B.H. Wyaaba 1 located ca 415 km farther south. The diorite is also extensively altered but is only slightly deformed and retains some relict primary igneous grains. The diorite has a low to moderate response on aeromagnetic images in contrast to the relative high magnetisation shown by the granitic gneiss forming the basement in drill hole Z.C.L. Weipa 1. It mainly intrudes rocks of the Kowanyama Province, which are characterised by an overall relatively uniform low magnetic response.

These granitoids were emplaced during the waning of a major late Paleoproterozoic–early Mesoproterozoic tectonothermal event that affected north Queensland. The event was accompanied by greenschist–granulite facies metamorphism and, according to Blewett &amp; Black (1998) it marked the termination of the first major crust-forming period following the ca 1880–1850 Ma Barramundi Orogeny of Etheridge et al. (1987).

Zircons analysed from the third sample, a carbonaceous siltstone from the concealed Gamboola Basin yielded a 238U/206Pb maximum depositional age of 279.9 ± 2.4 Ma, thereby supporting the early Permian age of deposition proposed by some previous investigators. Interestingly, although the basin is located in the Townsville–Mornington Island Belt, the detrital zircon population is dominated by ca 1572 Ma grains implying the local Etheridge and Croydon provinces were the main sources of the detritus in the siltstone rather than the surrounding Kennedy Igneous Association.

Tags: Carpentaria Lowlands, Geochronology, National Collaborative Framework (NCF), Published_External, Queensland, U-Pb SHRIMP geochronology, basement, zircon
Organization: Geoscience Australia Data
Regional plate tectonics and the evolution of Australia's passive continental margins

The divergent, passive continental margins around Australia have evolved through the progressive dissection of eastern Gondwanaland in five separate seafloor-spreading episodes. The earliest episode occurred 155 m.y. ago off northwestern Australia. The latest episode started 55 m.y. ago south of Australia and continues on the Southeast Indian spreading ridge to the present. The geological and structural evolution of each passive margin was a protracted process. The onset of seafloor spreading (breakup) was preceded by more or less extensive sedimentary basin subsidence. Non-volcanic rift-grabens, with fairly clear boundary faults, began evolving 40-50 m.y. before breakup. Such rifting was often preceded by a broader intra-cratonic style of basin subsidence straddling the incipient continent-ocean boundary between 50 and 100 m.y. before breakup. Rift and infrarift sedimentation rates declined exponentially towards the breakup unconformity. Postbreakup subsidence was again rapid, but exponentially decreased with time. Immediate postbreakup sedimentation was usually interrupted by submarine erosion in the shallow, but rapidly subsiding, ocean basin. Prograding marine shelf conditions prevailed from about 20-40 m.y. after breakup along all margins. The dominant driving mechanism of postbreakup subsidence seems clearly to be lithospheric thermal contraction caused by the removal, by seafloor spreading, of a thermal anomaly from beneath the continental margin. The driving mechanism of the rift-phase subsidence is far less clear. Simple surface observations do not unambiguously discriminate between sudden pull-apart rifting, finite rate stretching, and deep crustal metamorphic contraction. All processes may occur to at least some extent and dominate at different times. However, the apparent absence of both extensive rift volcanics, and transform / transcurrent faulting at rift offsets, plus the non-conformity of rift, breakup, and basement structural patterns, argue against stress-driven stretching as a crucial mechanism. Specific model predictions of crustal structure, heat flow and cumulative sedimentation pattern favour a dominantly metamorphic subsidence mechanism, although this fails to account fully for some thin continental crust near continent-ocean boundaries.

Tags: AUS, Earth Sciences, GA Publication, Journal, Published_External, marine
Organization: Geoscience Australia Data
Australia’s Future Energy Resources (AFER) Project - Regional Geology of the Pedirka and western Eromanga basins

As part of the Exploring For The Future (EFTF) program, the Australia’s Future Energy Resources (AFER) project has investigated the potential of energy resource commodities in the Pedirka/western Eromanga basins region targeting conventional and unconventional hydrocarbons as well as evaluating the suitability of sedimentary sections to store carbon dioxide.

The interpretation of new biostratigraphic and reprocessed seismic data provided new insights into the regional geology of this previously explored region. The Permian, Triassic and Jurassic depositional history of the study area is largely recorded by extensive fluvial-lacustrine sediments, including changes from braided to meandering river systems and sustained periods of flood-plain environments in which thick sequences of coal-bearing strata developed. During the Cretaceous, expanding shallow marine environments were established in the western part of the Pedirka/western Eromanga region.

Age-control obtained from palynological analysis and the mapping of key seismic horizons yielded an improved understanding of the extent and character of unconformities which define breaks and changes in depositional processes. Results from new regional stratigraphic correlations initiated a comprehensive review of previously established basin definitions in the greater Pedirka/western Eromanga area. 

While confirming the stacked nature of these basins which hold sedimentary records from the early Paleozoic to the Late Cretaceous, changes to stratigraphic basin boundaries have been applied to more correctly reflect the impact of unconformity related depositional breaks. As a result, the Lower and Middle Triassic Walkandi Formation is now assigned to the upper section of the Pedirka Basin, while the Upper Triassic Peera Peera Formation represents commencement of deposition in the western Eromanga Basin, thereby abandoning the recognition of the Simpson Basin as a separate Triassic depocenter.&nbsp;





Tags: Australia’s Future Energy Resources, Chronostratigraphy, EFTF – Exploring for the Future, Energy Resource Assessment Module, Pedirka Basin, Published_External, Stratigraphy, Stratigraphy (incl. biostratigraphy, sequence stratigraphy and basin analysis), structural architecture, western Eromanga Basin
Organization: Geoscience Australia Data
Geochemical characteristics of hydrocarbon families and petroleum systems, Bonaparte Basin

The Vulcan Sub-basin has been actively explored for over twenty years, with oil production from the Jabiru and Challis-Cassini fields, and the depleted Skua Field, all of which were sourced by the Upper Jurassic Lower Vulcan Formation within the Swan Graben. The need to discover other oil-prone petroleum systems led to this study focussing on oils that have a different composition to those of the aforementioned oils. Geochemical analyses (bulk and compound-specific isotopes, GC and GC-MS of saturated and aromatic hydrocarbons) have characterised the Vulcan Sub-basin oils and condensates into three families (Fig 1); a marine oil family (with some terrigenous influence) comprising Jabiru, Challis, Skua, Talbot and Tenacious; a terrestrially-influenced oil family comprising Maret, Montara, Padthaway and Bilyara which have more varied geochemistry; and, a family of condensates from Tahbilk, Swan and Eclipse. The composition of these condensates is more reflective of reservoir alteration effects (such as leakage and gas flushing) than the type of organic matter in their source rocks. The terrestrially-influenced oil family is located in the southernmost part of the Vulcan Sub-basin and in the northern Browse Basin, most probably having being source from the Lower-Middle Jurassic Plover Formation.  The Plover Formation contains liquid-prone source rocks within the Skua Trough, albeit immature for hydrocarbon generation. Similar source rocks are believed to occur beneath the Swan and Paqualin grabens since oils with mixed composition are found at Puffin, Pituri and Oliver.

Tags: AU-NT, Conference Paper, Earth Sciences, External Publication, Published_External, organic geochemistry, petroleum exploration, petroleum geology
Organization: Geoscience Australia Data
Sedimentological Analyses from Deepsea Cores taken off Southwest Victoria, and Western and Southern Tasmania

Since 1985 the Bureau of Mineral Resources (BMR) has been involved in three coring cruises off southwest Victoria and Tasmania. A great amount of laboratory work has been done on the cores, generally on samples taken at 20cm intervals, by technicians in BMR's Division of Marine Geosciences and Petroleum Geology, and the aim of this record is to document the results.

The analytical work has been designed to be complementary to other scientific studies on the cores: physical descriptions, smear slide descriptions, and palaeontological examinations. The aim of all the work has been to adequately describe the variations which have taken place with time in the cores, and to relate these back to regional and local changes in depositional environment. The final intention of the studies is to build up a model of sedimentation on the continental margin which, in conjunction with reflection seismic data, can be used to interpret depositional packages in much older sequences.

The first sampling cruise was carried out in early 1985, aboard the West German research vessel Sonne (S0-36C) in a co-operative venture between BGR (German Geological Survey) and BMR. This survey took 43 cores off west Tasmania and on the South Tasman Rise (Figures 1B and 2) These cores varied in length from 0.55m to 7.78m (Table 1),and full station data are given in Hinz et al. (1985). Bolton et al. (1988)described six cores from the South Tasman Rise containing ferro manganese crust and nodules. Grainsize and CaCO3 analyses for 9 Sonne cores are presented in this Record.

The second sampling cruise, BMR Cruise 67, was carried out by BMR's research vessel Rig Seismic in 1987, off southwest Victoria and western Tasmania (Figures lA and 3). This survey took 54 cores varying in length from 0.10m to 3.64m (Table 2), and full station data are given in Exon, Lee et al. (1987) and Exon, Lee et al. (1989). Grainsize and CaCO3 analyses on 35 cores carried out at BMR are reported here, as well as TOC (Total Organic Carbon %) and CaCO3 analyses from low in 15 cores carried out by AMDEL.
The third sampling cruise, BMR Cruise 78, was carried out by Rig Seismic in 1988, off western Tasmania (Figures 4 and 5). Altogether 38 core stations were occupied, of which 22 were successful. Core recovery varied from 0.02m to 7.33m (Table 3) and full station data will be given in Exon, Lee and Hill (1989). Grainsize and CaCO3 analyses from 10 cores are reported here.

Tags: AU-TAS, AU-VIC, Earth Sciences, GA Publication, Published_External, Record, marine, marine survey
Organization: Geoscience Australia Data