Topic
 

geoscientificInformation

169 record(s)
 
Type of resources
Topics
Keywords
Contact for the resource
Provided by
Years
From 1 - 10 / 169
  • Categories  

    Rocky reefs form an important habitat on the continental shelf and one subject to disproportionate fishing pressure given the high productivity of this habitat relative to adjacent sandy seabed. Despite this, little is known of the extent and nature of these systems beyond their value to the fishing industry. This project collated all known mapping data from government and industry (including data acquired during CERF and NERP Hubs) to provide an updated map of this key habitat around Australia. A geomorphological classification system is also being developed for these reefs, and associated cross-shelf habitats with the aim of it being accepted and adopted nationally, and it is being tested and refined for biological applicability. This record describes the national habitat map data product generated from multiple datasets collated as part of NESP MBH Project D3. The individual habitat mapping datasets collected as part of the data collation process have also been published and are linked to this record.

  • Categories  

    A comprehensive and detailed multibeam sonar-based map of the shelf-break region of the Central Flinders Commonwealth Marine Reserve (CMR). It illustrates the extent that several canyon-head incisions are present in this region, and that inset from the shelf-break is a relatively extensive area of cross-shelf reef. Some of the canyon-head incisions are characterised by exposed reef areas, and these are indicated by localised regions of rapid change in depth. The cross-shelf reef is generally very low profile, but characterised by distinct reef ledges where bedding planes in the sedimentary rock types have eroded. These ledges, often between 1-2 m in height, can run for several kilometres as distinct features. The method of data extraction is based on Lucieer (2013). Three are three classes of seafloor map- one from GEOBIA, one from digitisation and one from Probability of Hardness based on Angular Profile Correction. Lucieer, V (2013) NERP broad-scale analysis of multibeam acoustic data from the Flinders Commonwealth Marine Reserve, Prepared for the National Environmental Research Program. Internal report. IMAS, Hobart, TAS [Contract Report]

  • Sediment cores were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator from January 14th to March 5th 2017 (IN2017_V01; Armand et al., 2018). This marine geoscience expedition, named the “Sabrina Sea Floor Survey”, focused notably on studying the interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. The cores were collected using a multi-corer, allowing to sample the surface of the sediment (top ~ 30cm). The cores were then sliced every centimetre, wrapped up in plastic bags, and stored in the fridge. Radiocarbon (14-C) ages were measured to build an age model for future paleo-reconstructions. Sediment samples were pre-treated in the IMAS Sediment Lab (UTAS, Hobart, Australia). Samples (~ 2 g) from the multi-cores MC01, MC03 and MC06 were dried, ground and acidified with HCl for carbonate removal using sterilised beakers. Dried and ground samples were then packed into sterilised aluminium foil and sent to DirectAMS (Radiocarbon Dating Service, USA) for 14C analysis by Accelerator Mass Spectrometer (AMS). Results were corrected for isotopic fractionation with an unreported δ13C value measured on the prepared carbon by the accelerator. References L.K. Armand, P.E. O’Brien and On-board Scientific Party. 2018. Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report, Research School of Earth Sciences, Australian National University: Canberra.

  • Amery Ice Shelf AM05 borehole drilled mid-December 2009. Sub-shelf water profiling measurements conducted over a period of a few days. Partial video recording of borehole walls and sea floor benthos. Collection of targeted ice core samples. Sediment sample collected from sea floor. Long term monitoring instruments installed (thermistors in ice, 3 x CTD in ocean cavity). This is a parent record - see the child records for further information. Some general readme documents are available for download from the provided URL.

  • Trace metal concentrations are reported in micrograms per gram of sediment in core C012-PC05 (64⁰ 40.517’ S, 119⁰ 18.072’ E, water depth 3104 m). Each sediment sample (100-200mg) was ground using a pestle and mortar and digested following an initial oxidation step (1:1 mixture of H2O2 and HNO3 acid) and open vessel acid on a 150 degree C hotplate using 2:5:1 mixture of concentrated distilled HCl, HNO3 and Baseline Seastar HF acid. After converting the digested sample to nitric acid, an additional oxidation step was performed with 1:1 mixture of concentrated distilled HNO3 and Baseline Seastar HClO4 acid. A 10% aliquot of the final digestion was sub-sampled for trace metal analyses. Trace metal concentrations were determined by external calibration using an ELEMENT 2 sector field ICP-MS from Thermo Fisher Scientific (Bremen, Germany) at Central Science Laboratory (University of Tasmania). The following elements were analysed in either low (LR) or medium resolution (MR): Sr88(LR), Y89(LR), Mo95(LR), Ag107(LR), Cd111(LR), Cs133(LR), Ba137(LR), Nd146(LR), Tm169(LR), Yb171(LR), Tl205(LR), Pb208(LR), Th232(LR), U238(LR), Na23(MR), Mg24(MR), Al27(MR), P31(MR), S32(MR), Ca42(MR), Sc45(MR), Ti47(MR), V51(MR), Cr52(MR), Mn55(MR), Fe56(MR), Co59(MR), Ni60(MR), Cu63(MR), Zn66(MR).

  • Publicly available bathymetry and geophysical data can be used to map geomorphic features of the Antarctic continental margin and adjoining ocean basins at scales of 1:1-5 million. These data can also be used to map likely locations for some Vulnerable Marine Ecosystems. Seamounts over a certain size are readily identified and submarine canyons and mid ocean ridge central valleys which harbour hydrothermal vents can be located. Geomorphic features and their properties can be related to major habitat characteristics such as sea floor type (hard versus soft), ice keel scouring, sediment deposition or erosion and current regimes. Where more detailed data are available, shelf geomorphology can be shown to provide a guide to the distribution in the area of the shelf benthic communities recognised by Gutt (2007). The geomorphic mapping method presented here provides a layer to add to benthic bioregionalistion using readily available data. An AADC maintained copy of these data are publicly available for download from the provided URL. The master copy of these data are attached to the metadata record held at Geoscience Australia (see the provided URL).

  • Sediment cores were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator from January 14th to March 5th 2017 (IN2017_V01; Armand et al., 2018). This marine geoscience expedition, named the “Sabrina Sea Floor Survey”, focused notably on studying the interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. The cores were collected using a multi-corer (MC) and a Kasten corer (KC). The MC were sliced every centimetre, wrapped up in plastic bags, and stored in the fridge. The KC was sub-sampled using an u-channel; and sliced every centimetre once back the home laboratory (IMAS, UTAS, Hobart, Australia). This dataset presents concentrations of major and trace elements measured in bulk multi-cores sediment samples collected during the IN2017_V01 voyage. The data include the sampling date (day/month/year), the latitude and longitude (in decimal degrees), the seafloor depth (in meter), the sediment core ID, the sediment depth (in cm), and the concentrations (in ppm or μg/g) of a suite of elements. This dataset presents concentrations of major and trace elements measured in bulk sediment samples collected during the IN2017_V01 voyage. The data include the sampling date (day/month/year), the latitude and longitude (in decimal degrees), the seafloor depth (in meter), the sediment core ID (KC14), the sediment depth (in cm), and the concentrations (in ppm or μg/g) of a suite of elements. About 200 mg of dried and ground sediment were weighed into a clean Teflon vial and oxidized with a mixture of concentrated HNO3 and 30% H2O2 (1:1). Samples were then digested in open vials using an acid mixture comprising 10 mL HNO3, 4 mL HCl, and 2 mL HF, at 180°C until close to dryness. Digested residues were converted to nitric form before being oxidised with a mixture of 1 mL HNO3 and 1 mL HClO4 at 220°C until fully desiccated. Samples were finally re-dissolved in 4 mL 7.5 M HNO3. A 400 μL aliquot was removed from the 4 mL digest solution and diluted ~2500 times in 2% HNO3 for trace metals analysis by Sector Field Inductively Coupled Mass Spectrometry (SF-ICP-MS, Thermo Fisher Scientific, Bremen, Germany) at the Central Science Laboratory (UTAS, Hobart, Australia). Indium was added as internal standard (In, 100 ppb). 88Sr, 89Y, 95Mo, 107Ag, 109Ag, 111Cd, 133Cs, 137Ba, 146Nd, 169Tm, 171Yb, 185Re, 187Re, 205Tl, 208Pb, 232Th, 238U, 23Na, 24Mg, 27Al, 31P, 32S, 42Ca, 47Ti, 51V, 52Cr, 55Mn, 56Fe, 59Co, 60Ni, 63Cu and 66Zn were analysed using multiple spectral resolutions. Element quantification was performed via external calibration using multi-element calibration solutions (MISA suite, QCD Analysts, Spring Lake, NJ, USA). Raw intensities were blank and dilution corrected. References L.K. Armand, P.E. O’Brien and On-board Scientific Party. 2018. Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report, Research School of Earth Sciences, Australian National University: Canberra.

  • Because of the inaccessibility of the deep-ocean floor, our knowledge about the composition and structure of the oceanic crust is very limited. Macquarie Island is the only fragment of ocean crust exposed above sea-level in the world, providing a unique opportunity to study the ocean crust directly in unprecedented detail. From the abstract of the referenced paper: Macquarie Island preserves largely in-situ Miocene oceanic crust and mantle formed at a slow-spreading ridge. The crustal section on the island does not conform to a simple 'layer cake pseudo-stratigraphy', but is the result of multiple magmatic episodes. Macquarie Island crust did not grow by top-down cooling, but rather from the base up. Peridotites cooled first and formed the basement into which gabbro plutons were intruded. This was followed by cooling and deformation, and by intrusion of dykes that fed a sheeted dyke-basalt complex. Finally, lava filled grabens were formed. These relative age relations rule out simple co-genetic relations between rock units.

  • Metadata record for data from ASAC Project 2592 See the link below for public details on this project. The Southern Ocean is one the most significant regions on earth for regulating the build up of anthropogenic carbon in the atmosphere, and the capacity for carbon uptake in the region could be altered by climate change. The project aims to use repeat ocean sections to detect anthropogenic carbon storage, identify key processes regulating the amount of storage, and to test models that predict future uptake. The data are broken down by season and voyage, and a word document providing further details about the project is also available as part of the download file.

  • Sediment cores were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator from January 14th to March 5th 2017 (IN2017_V01; Armand et al., 2018). This marine geoscience expedition, named the “Sabrina Sea Floor Survey”, focused notably on studying the interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. The cores were collected using a multi-corer, allowing to sample the surface of the sediment (top ~ 30cm). The cores were then sliced every centimetre, wrapped up in plastic bags, and stored in the fridge. The sediment samples were dated using 210-Pb analysis for future paleo-reconstructions. 210-Pb is a radioisotope which allows to date sediment back to 150 years, which is ideal for surface (i.e. recent) sediment samples. Sediment samples were dried, ground and sent to Edith Cowan University (Joondalup, Western Australia) for sample preparation and analysis. Total 210Pb was determined through the analysis of its granddaughter 210Po by alpha spectrometry after complete sample digestion using an analytical microwave in the presence of a known amount of 209Po added as a tracer (Sanchez-Cabeza et al., 1998). The concentrations of excess 210Pb were determined as the difference between total 210Pb and 226Ra (supported 210Pb), the later determined by gamma spectrometry through the measurement of its decay products 214Pb and 214Bi using a HPGe detector (CANBERRA, Mod. SAGe Well). References L.K. Armand, P.E. O’Brien and On-board Scientific Party. 2018. Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report, Research School of Earth Sciences, Australian National University: Canberra. Sanchez-Cabeza J. A., Masqué P. and Ani-Ragolta I. (1998) 210Pb and 210Po analysis in sediments and soils by microwave acid digestion. J. Radioanal. Nucl. Chem. 227, 19–22.