AndreaBozzo/ceres-open-data-index huggingface dataset:
AMSIS Offshore Minerals Legacy MapServer

The data contained in this service is not authoritative and has not been updated since 2006. This web service contains the legacy data found in the Australian Marine Spatial Information System (AMSIS) between 2006 and 2015, with a currency date of 2006. To honour the original licensing arrangements with the data holders, only the WMS is available. Users will need to contact the agency responsible for the data to check current validity and spatial precision.

Tags: AMSIS, Australia, Earth Sciences, MapServer, Offshore Minerals, Published_External, legacy, web service
Organization: Geoscience Australia Data
Video and still images from SOL4769 (Carnarvon Shelf)

The Carnarvon Shelf Survey (SOL4769, GA survey #0308) was conducted on the R.V. Solander in collaboration with the Australian Institute of Marine Science between 12 August and 15 September 2008. The survey was operated as part of the Surrogates Program of the CERF Marine Biodiversity Hub. The survey was completed under a Memorandum of Understanding between GA and the AIMS and represents the first of three surveys planned under this agreement. The objective was to collect high-quality, accurately co-located data to enable the robust testing of a range of physical parameters as surrogates of patterns of benthic biodiversity. Underwater video footage and still images were collected from 122 stations from water depths of 13-125 m, although video quality varies among transects and some still images were not of suitable quality for analysis. Images from the still camera can be found in 'Image Library', and images from towed video screen captures can be found in 'Tow Video Stills'. Image files from screen captures are named according to area (1 = Mandu, 2 = Point Cloates, 3 = Gnarloo) followed by the station number and video identifier (TVA1). For example, 2_032TVA1 would represent a towed video transect from Station 32 at Point Cloates. See GA Record 2009/02 (Geocat #68525) for further details. Video footage was recorded to mini DV tapes, and copied to digital format.  The original mini DV tapes are archived at AIMS-WA.

Tags: CERF, Earth Sciences, HVC_144640, Multimedia, Published_External, marine
Organization: Geoscience Australia Data
Quantitative mapping of the East Australian Current encroachment using time series Himawari-8 sea surface temperature data

The East Australian Current (EAC) is a complex and highly dynamic western boundary current (WBC) component of the South Pacific Gyre. The interaction between the EAC and the continental shelf significantly influences the coastal ocean dynamics and the marine ecosystem off the southeast coast of Australia. In this study, we attempted to map the spatial structure of the sea surface temperature (SST) signature of the EAC system using Himawari-8 SST data, and to investigate the spatial and temporal evolution of the EAC encroachment for the period July 2015 to Sept 2017. The very high spatiotemporal resolution of Himawari-8 SST images has enabled the mapping of the highly dynamic EAC using a Topographic Position Index (TPI) method. The results demonstrated that the TPI mapping was able to capture the complex spatial structure of the EAC system, based on which the spatial variability and temporal evolution of EAC’s meanders, offshoots, separation, eddies, and extensions along its path have been clearly documented. Using an eddy-resolving, data assimilating numerical ocean model, we were able to relate the EAC's SST signature with its surface current speed signature, with an overall area ratio of overlap ~60% between the two signatures. Temporal wavelet analyses indicated that the variability of the EAC encroachment is dominated by an eddy-shedding timescale, being 65~80 days upstream and 90~100 days downstream of the EAC separation point. In the upstream, the EAC’s proximity to the coast also exhibited seasonal cycle in the 2 year (26 months) study period, with the encroachment being stronger during austral summer and weaker during austral winter. Off the eastern coast of Tasmania, powerful summer pulses of the EAC encroachment were observed, which is an expression of the seasonality of the EAC boundary flow in this region. Upstream, we believe that the “encroach and accelerate” mode of the EAC would drive coastal upwelling which can occur all year round with local maximum typically in summer. Downstream, the “encroach and decay” mode of the western arm of the EAC or its eddies is less likely to induce and sustain bottom water uplift. The seasonal current sheer previously observed upstream on the continental shelf is believed to be a combined effect of the stronger EAC encroachment and the enhanced temperature difference between shelf and EAC waters (i.e. thermal wind effect) in summer compared to winter.

<b>Citation:</b> Xie, S., Huang, Z., Wang, X. H., &amp; Leplastrier, A. (2020). Quantitative mapping of the East Australian Current encroachment using time series Himawari‐8 sea surface temperature data. <i>Journal of Geophysical Research: Oceans</i>, 125, e2019JC015647. https://doi.org/10.1029/2019JC015647

Tags: EARTH SCIENCES, East Australian Current, Published_External, current intrusions, remote sensing
Organization: Geoscience Australia Data
First Discovery of Dolomite and Magnesite in Living Coralline Algae and its Geobiological Implications

Dolomite is a magnesium rich carbonate mineral abundant in ancient coral reef formations [1-3] yet very little is found forming in modern sedimentary environments.  For over 150 years this conundrum has led to various theories being put forward about dolomite formation, however none have solved the so called `Dolomite Problem'[1].   It has generally been considered a  post-depositional diagenetic process [2, 3], despite little experimental success at replicating dolomite formation in normal sea water conditions [4].  Here we show dolomite is in fact forming with living crustose coralline algae Hydrolithon onkodes, a species growing prolifically in coral reefs globally.  Chemical micro-analysis of the coralline skeleton reveals that not only are the cell walls calcitised, but that the cell spaces are typically filled with magnesite, rimmed by dolomite, or both.  Thus there are at least three mineral phases present (magnesium calcite, dolomite and magnesite) rather than one or two (magnesium calcite and brucite) as previously thought[5-7]. Both the magnesium calcite and dolomite phases comprise a continuum of magnesium to calcium compositions, whereas magnesite is near ideal composition.  Using a mass balance approach we quantify potential dolomitisation of the coralline algae and can account for the total amount of dolomite found in a raised Pleistocene reef [2].  Our results are consistent with observed dolomites in coralline-algal rich environments in fossil reefs. This is the first time the presence of dolomite in living coralline algae has been confirmed.

Tags: Earth Sciences, External Publication, Published_External, Scientific Journal Paper, carbonate, geochemistry, marine
Organization: Geoscience Australia Data
5028 Block 3 (Northwest) Grid of potassium ground concentration with NASVD and standard reductions applied

The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.
This radiometric potassium grid has a cell size of  degrees (approximately 20m) and shows potassium element concentration of the Narryer in units of percent (or %). The data used to produce this grid was acquired in 2024 by the WA Government, and consisted of 415090 line-kilometres of data at 100m line spacing and 50m terrain clearance.

Tags: Australia, EARTH SCIENCES, Earth sciences, GADDS2.0, K, NCI, Published_External, WA, airborne digital data, gamma-ray, geophysical survey, geophysics, grid, potassium, rad, radiometrics, raster, spectrometry, survey 5028
Organization: Geoscience Australia Data
National Gravity Compilation 2019 includes airborne CSCBA image

Gravity data measure small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. 
This National Gravity Compilation 2019 includes airborne CSCBA image is an image derived from the 2019 Australian National Gravity Grids B series. These gravity data were acquired under the project No. 202008. The grid used to produce this image has a cell size of 0.00417 degrees (approximately 435m). The data are given in units of um/s^2, also known as 'gravity units', or gu. This gravity anomaly grid is derived from ground observations stored in the Australian National Gravity Database (ANGD) as at September 2019, supplemented by offshore data sourced from v28.1 of the Global Gravity grid developed using data from the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration (NOAA), and National Geospatial-Intelligence Agency (NGA) at Scripps Institution of Oceanography, University of California San Diego. Out of the approximately 1.8 million gravity observations, nearly 1.4 million gravity stations in the ANGD together with Airborne Gravity surveys totaling 345,000 line km and 106,000 line km of Airborne Gravity Gradiometry were used to generate this grid. The ground gravity data used in this grid 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. Station spacing varies from approximately 11 km down to less than 1 km, with major parts of the continent having station spacing between 2.5 and 7 km. Airborne surveys have a line spacing ranging from 0.5 km to 2.5 km. The image shows complete Bouguer anomalies (B series) over Australia and its continental margins. Terrain corrections to gravity were calculated using both offshore bathymetry and onshore topography data.

Tags: Australia, B series, Bouguer, EARTH SCIENCES, Earth sciences, GADDS2.0, NCI, None, Published_External, complete, digital data, geophysical survey, geophysics, grav, gravity, image, national, raster, spherical cap, survey 202008
Organization: Geoscience Australia Data
Development, Composition and Age of Indurated Sand Layers in the Late Quaternary Coastal Deposits of Northern Moreton Bay, Queensland

Indurated sand is commonly found in Quaternary coastal deposits in a range of temperate and tropical environments. These horizons can record past regionally significant phases of soil development. Also, their lower hydraulic conductivity can produce locally perched water tables and they have been regarded as a potential source of iron in coastal waterways. Samples were analysed from exposures in sand mine pits at Beachmere and in the bank of an estuarine channel at Bells Creek in southeast Queensland. In these samples cements coat grains and usually partially infill interstitial pores. Distinctive cement forms are produced by different constituents that are dominantly kaolinite, amorphous organic-rich complexes or a mix of clay and amorphous material. Trace metal concentrations in the cements are lower than previously reported for soils and modern estuarine sediments in the region. Large-scale exposures at Beachmere reveal that in addition to the podzolisation process, mineral and amorphous organic-rich cements also precipitate from groundwater that preferentially flows through the poorly sorted coarser sediments. OSL and TL ages for the deposits examined indicate that induration occurs over long periods of time, 100,000 ? 70,000 years. Only incipient induration has developed over the last 16,000 ? 2,600 years. The degree of induration, however, is not always proportional with age and is strongly influenced by the texture of the deposits, with gravely sands (OSL age 76,700 ?6,500 yr) exhibiting a greater degree of induration than an adjacent medium to coarse sand (98,000 ?9,900 yr).

Tags: AU-QLD, Earth Sciences, External Publication, Published_External, Scientific Journal Paper, marine
Organization: Geoscience Australia Data
The elusive Cook volcano and other submarine forearc volcanoes in the Solomon Islands

Submarine volcanoes reported from the forearc region of the New Georgia Group are anomalously close to the line of northeast wards subduction of the Woodlark Basin. Kavachi is a basalt- andesite volcano that rises nearly 1000 m above the sea floor south of Vangunu. It is frequently active and sometimes builds subaerially.  A seamount 9 km northeast of Kavachi may also be a youthful volcano.  Kana Keoki volcano, southwest of Rendova, is andesite to rhyolite in composition. It has not been recorded in eruption, and rises to within 700 m of sea level from a base at around 2500 m. Activity ascribed to Cook submarine volcano west of Rendova was reported for 1963 - 4, and a shoal was reported to have been found by leadline sounding, but no volcano was found by detailed bathymetric surveys in 1979 and 1981. The activity probably consisted largely of hydrothermal blow-outs from a sea-floor vent (or vents) 1300 m below sea level, rather than from a volcano. Another submarine volcano has been reported to lie 25 km west of Kavachi, and southeast of Tetepare, but no sign of it was seen on a bathymetric profile run through this location.  The New Georgia Group forearc region is very poorly surveyed bathymetrically. A single swathe-mapping sonar survey would show how many submarine volcanoes are present in the region and where they are located, prior to further sampling.

Tags: Earth Sciences, GA Publication, Journal, Published_External, marine
Organization: Geoscience Australia Data
Refining the Moho across the Australian continent

In recent years there has been a considerable expansion of deployments of portable seismic stations across Australia, which have been analysed by receiver function or autocorrelation methods to extract estimates of Moho depth. An ongoing program of full-crustal reflection profiles has now provided more than 25,000 km of reflection transects that have been interpreted for Moho structure. The Moho dataset is further augmented by extensive marine reflection results. These new data sources have been combined with earlier refraction and receiver function results to provide full continental coverage, though some desert areas remain with limited sampling. 
The dense sampling of the Moho indicates the presence of rapid changes in Moho depth and so the Moho surface has been constructed using an approach that allows different weighting and spatial influence depending on the nature of the estimate. The inclusion of Moho results from gravity inversion with low weighting helps to resolve the continent-ocean transition and to provide additional control in the least sampled zones. The refined distribution indicates the presence of widespread smaller-scale variations in Moho structure. Strong lateral contrasts in crustal thickness remain, but some have become more subdued with improved sampling of critical areas. The main differences from earlier results lie in previously poorly sampled regions around the Lake Eyre Basin, where additional passive seismic results indicate somewhat thicker crust though still witha strong contrast in crustal thickness to the cratonic zone to the west.

Appeared in Geophysical Journal International, January 2023

Tags: AusArray, Australia, Body waves, Controlled source seismology, Crustal Structure, EFTF – Exploring for the Future, Published_External, Seismology and seismic exploration
Organization: Geoscience Australia Data
Planktonic foraminifera, age of sediments and polarity reversals, New Britain, Papua New Guinea

Samples from the Rudiger Point-Cape Ruge area, New Britain, are not from a conformable late Miocene-earliest Pliocene sequence, as was presumed by previous workers, but rather are of two age groups, one of general middle Miocene age, and a younger group of late Miocene age. A sample of volcanolithic sandstone, NG34B, is of late Pliocene-middle Pleistocene, Zone N.21-Zone N.22, age; this is the youngest marine sediment yet recognised in New Britain. Planktonic Zone N.18 is correlated, at least in part, with a normally magnetised interval.

Tags: Earth Sciences, GA Publication, Journal, PNG, Published_External
Organization: Geoscience Australia Data
The role of soil flux and soil gas in the characterisation of a surface CO2 leak: A case study in Qinghai, China

Following the drilling of a shallow natural CO2 reservoir at the Qinghai research site, west of Haidong, China, it was discovered that CO2  was continuously leaking from the wellbore due to well-failure. The site has become a useful research facility in China for studying CO2  leakage and monitoring technologies for application to geological storage sites of CO2. During an eight day period in 2014, soil gas and soil flux surveys were conducted to characterise the distribution, magnitude and likely source of the leaking CO2 .

Two different sampling patterns were utilised during soil flux surveys. A regular sampling grid was used to spatially map out the two high-flux zones which were located 20–50 m away from the wellhead. An irregular sampling grid, with higher sampling density in the high-flux zones, allowed for more accurate mapping of the leak distribution and estimation of total field emission rate using cubic interpolation. The total CO2  emission rate for the site was estimated at 649-1015 kgCO2/d and there appeared to be some degree of spatial correlation between observed CO2  fluxes and elevated surface H2O fluxes.

Sixteen soil gas wells were installed across the field to test the real-time application of Romanak et al.’s (2012) process-based approach for soil gas measurements (using ratios of major soil gas components to identify the CO2 source) using a portable multi-gas analyser. Results clearly identified CO2  as being derived from one exogenous source, and are consistent with gas samples collected for laboratory analysis. Carbon-13 isotopes in the centre of each leak zone (−0.21‰ and −0.22‰) indicate the underlying CO2  is likely  sourced from the thermal decomposition of marine carbonates.

Surface soil mineralisation (predominantly calcite) can be used to infer prior distribution of the CO2  hotspots and as a consequence highlighted plume migration of 20m in 11 years. The broadening of the affected area beyond the wellbore at the Qinghai research site markedly increases the area that needs surveying at sufficient density to detect a leak. This challenges the role of soil gas and soil flux in a CCS monitoring and verification program for leak detection, suggesting that these techniques may be better applied for characterising the source and emission rate of a CO2  leak, respectively.

<b>Citation:</b> I.F. Schroder, H. Zhang, C. Zhang, A.J. Feitz, The role of soil flux and soil gas monitoring in the characterisation of a CO2 surface leak: A case study in Qinghai, China, International Journal of Greenhouse Gas Control, Volume 54, Part 1, 2016, Pages 84-95, ISSN 1750-5836, https://doi.org/10.1016/j.ijggc.2016.07.030.

Tags: CO2 leak, China, EARTH SCIENCES, Published_External, emissions, gas migration, soil flux, soil gas, surface monitoring, well failure
Organization: Geoscience Australia Data
Stable isotope and chemical studies of volcanic exhalations and thermal waters, Rabaul caldera, New Britain, Papua New Guinea

Thermal waters in Matupi Harbour and Sulphur Creek, Rabaul caldera have D/H and O18/O16 ratios that are indicative of a mixed source. They are the result of mixing of local meteoric waters with hot water of marine origin. The stable isotope data are grouped into distinct areas close to the meteoric water line. They suggest that the thermal systems away from the shoreline are dominated by meteoric water and that warmed sea water only enters the springs at the shoreline. Low temperature (100Â°C) fumarolic exhalations from Tavurvur and Rabalankaia volcanoes consist largely of recycled meteoric water. These conclusions conflict in part with those drawn from anion ratio and trace metal contents which were inferred by previous authors to be consistent with an hypothesis of modified sea water origin. We suggest that the chemistry of these acid, mineralised geothermal waters is a reflection of their later, near surface, history and does not necessarily give a correct picture of their ultimate origin. The enhanced Fe, Mn, and Zn values of the Matupi springs are a function of the leaching potential of geothermal fluids at elevated temperatures, and of the chemistry of the porous and chemically reactive rocks through which they pass.

Tags: Earth Sciences, GA Publication, Journal, PNG, Published_External
Organization: Geoscience Australia Data
Linking patterns and processes on a tropical sediment-starved shelf: Insights from cluster analysis on physical and geochemical variables

Geoscience Australia undertook seabed mapping surveys in the eastern Bonaparte Gulf in 2009/2010 to deliver integrated information relevant to marine biodiversity conservation and offshore infrastructure development. The survey objectives were to characterise the physical, chemical and biological properties of the seabed, document potential geohazards and to identify unique or sensitive benthic habitats and collect baseline information on these habitats.  Different clustering methods were applied to a 124 sample dataset comprising 74 physical and geochemical variables which describe organic matter (OM) reactivity/quantity/source and geochemical processes relevant to biodiversity. Infauna data were used to assess different groupings because they are an important food source for epibenthic crustaceans and fish and purveyors of ecosystem services including nutrient cycling and mineralisation. Clusters based on physical/geochemical data discriminated infauna better than geomorphic features. Major variations amongst clusters included grainsize and a cross-shelf transition in from authigenic-Mn /As enrichments (inner shelf) to authigenic-P enrichment (outer shelf) which relate to energy levels and sediment oxygen status. Groups comprising raised features had the highest reactive OM concentrations (e.g. based on  low chlorin indices and C:N-ratios, and high k) and benthic algal -13C signatures. Surface area normalised OM concentrations higher than continental shelf norms were observed in association with: (i) low -15N, inferring Trichodesmium input; and (ii) pockmarks. The pockmarks are shown to impart bottom-up controls on seabed chemistry and cause inconsistencies between bulk and pigment OM pools. The geochemical data and clustering methods provide insight into ecosystem processes which influence biodiversity patterns in the region.  Low Shannon-Wiener diversity occurred in association with low porewater pH and evidence for low sediment redox status and high energy levels, while the highest beta-diversity was observed at euphotic depths. Pair-wise ANOSIM results for infauna are brought together in a summary model which highlights the influence of the clusters on beta diversity.

Abstract presented at GEOHAB 5-9 May 2014 Lorne, Australia

Tags: AU-NT, Earth Sciences, Published_Internal, marine
Organization: Geoscience Australia Data