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Sea floor

21 record(s)
 
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  • High velocity friction experiments. In this study, new samples recovered by IODP (Integrated Ocean Drilling Program) Exp. 362 from incoming Indian plate sediments will be used to investigate the frictional behavior of these sediments en-route to the plate boundary interface. The UK IODP Moratorium award will be used to achieve 5 Strategic Objectives: SO 1 - identify the characteristics of the sedimentary sections to optimize the sampling strategy for friction experiments based upon onboard sedimentology, petrology, geochemistry and in-situ logging profiles. This objective will benefit from the Exp. 362 Science Party work carried out during the cruise. SO 2 - acquire a quantitative data set of the mineral assemblages, fluid permeability, and porosity for each sample. SO 3 - measure their frictional dependence on slip, slip rate, slip velocity, and normal stress by performing experiments on the collected samples under deformation conditions typical of earthquakes using the high velocity rock friction apparatus SHIVA. SO 4 - monitor gas emission, humidity, and temperature variations during friction experiments using mass spectrometry, temperature and humidity measurements with the sensors installed on the rotary shear apparatus. SO 5 - analyse the experimental fault rock material using a multidisciplinary approach that involves microstructural analysis, mineralogy, and petrology so that proxy records may be reconstructed for plate interface seismic slip. Validate these against the seismological record. The ultimate goal is to incorporate the actual physical properties of the Sumatra-Andaman incoming sedimentary section within an improved theoretical earthquake rupture propagation model. This research will develop a new approach to the assessment of extreme near-trench tsunamogenic slip based on the analysis of incoming plate sediments. This approach is also applicable to other plate-boundary megathrusts (e.g. Japan Trench, Barbados). Future studies can also consider possible lateral variations in the lithological composition of the incoming plate/subduction plate boundary material.

  • The Seabed Geology 10k: Bristol Channel is a digital geological map portraying the distribution of the different geological substrate units (either of bedrock or unlithified deposits) present on the seabed at a 1:10 000 scale. Additionally, to the Seabed Substrate layer, this dataset also includes i) a Geomorphology layer, revealing the presence and distribution of seabed morphological and geomorphological features and ii) a Structural Geology layer, that delineates the principal structural features observed at rockhead. The bedrock geology is divided into seven stratigraphical units: Pembroke Limestone Group (PEMB); Mercia Mudstone Group (MMG); Penarth Group (PNG); the Lias Groups' St Mary’s Well Bay (STM), Lavernock Shales (LVN) and the Porthkerry (PO) members; and the Inferior Oolite Group (INO). The Lexicon code of the stratigraphical units is provided in parentheses, as defined in the ‘BGS Lexicon of Named Rock Units’. The superficial deposits mapped are comprised of only marine sediments that were classified based on their grain size. However, Folk classification was not used to define the sediment classes. The sediments are divided into Gravel (V); Sand and Gravel (XSG); Sand (S); Sand and Mud (XSM); Mud (M); and Gravel, Sand and Mud (XVSM). The RCS code of the stratigraphical units is provided in parentheses, as defined in the ‘BGS Rock Classification Scheme’.

  • Scanned geophysical records, reports and track charts from Tarmac (previously Lafarge Tarmac) aggregate industry marine surveys 1989 to 2004. The geophysical records include boomer seismic and side scan sonar data of varying quality. All records from 44 boxes of paper records have been scanned at BGS and are delivered online along with any additional digital file such as reports or data files. The data are stored as part of the National Geoscience Data Centre (NGDC) and the Marine Environmental Data and Information Network (MEDIN) Data Archive Centre (DAC) for Geology and Geophysics.

  • Data from Marine Conservation Zone (MCZ) surveys are archived in the MEDIN Data Archive Centre (DAC) for Geology and Geophysics at the British Geological Survey. This includes geology (Particle Size Analysis) data and multibeam backscatter data. Data are delivered via the BGS Offshore GeoIndex. Additional data are available on request enquiries@bgs.ac.uk. Other data types are archived with the other MEDIN DACs as appropriate (UKHO DAC for bathymetry data and DASSH DAC for biological data). https://www.gov.uk/government/collections/marine-conservation-zone-designations-in-england.

  • The British Geological Survey (BGS) holds an archive of multibeam backscatter data from BGS, Maritime & Coastguard Agency (MCA) and other organisations. The data are stored within the National Geoscience Data Centre (NGDC) and the Marine Environmental Data and Information Network (MEDIN) Data Archive Centre (DAC) for Geology and Geophysics. BGS works with the partner DAC for bathymetry at the United Kingdom Hydrographic Office (UKHO) to archive backscatter data. The majority of the data were collected and processed for the Maritime and Coastguard Agency (MCA) under the Civil Hydrography Programme (CHP). Backscatter data is useful for seabed characterisation for geological and habitat mapping. View the backscatter image layer and download backscatter data (geotiff) via the BGS Offshore GeoIndex www.bgs.ac.uk/GeoIndex/offshore.htm. The data underlying the images are available on request enquiries@bgs.ac.uk. If further backscatter processing is required, BGS can provide a quote. View and download the related bathymetry data via the UKHO INSPIRE portal https://www.gov.uk/guidance/inspire-portal-and-medin-bathymetry-data-archive-centre.

  • This is a 1:10,000 scale Bedrock geological map for some 800 km2 of the seabed across Weymouth Bay in Dorset. It joins seamlessly to the onshore BGS 1:10,000 scale Digital Geological Mapping (DiGMapGB-10) and therefore shows the coastal geology in detail. It comprises bedrock polygons, faults and limestone bed lines. The map was produced in 2015-16 by digitising against a seamless on- to offshore-shore elevation surface generated from high (1 m bin) resolution bathymetry and coastal Lidar data, collected as part of the Dorset Integrated Seabed Survey (DORIS) project and the Regional Coastal Monitoring Programme of England, made available by the Channel Coastal Observatory under the Open Government Licence. The map can be veiwed using the map viewer at www.bgs.ac.uk/research/marine/doris.html. This map has been produced under the auspices of the Marine Environmental Mapping Programme (MAREMAP), in collaboration between the BGS and the University of Southampton. The map itself should be referred to as: Westhead, R K, Sanderson, D J, Dix, J K. 2016. Bedrock map for the offshore Weymouth Bay area, with seamless coastal joint to BGS onshore (DiGMapGB-10) mapping. Bedrock Geology. 1:10 000 (Marine Environmental Mapping Programme, MAREMAP)

  • The BGS Seabed Geology 10k: Anglesey digital map portrays the distribution of the different types of bedrock and sediments that are interpreted to represent the dominant geology within to the top 1-2 metres of the seabed to the north-west of Anglesey, at a scale of 1:10 000. It also includes the distribution of the main seabed morphological and geomorphological features (e.g. drumlins, sandwaves) and the principal structural features observed at rockhead (fractures). This digital map is the result of the interpretation of two high-resolution, multibeam echo-sounder (MBES) bathymetry datasets: (i) the Off Skerries HI1420 survey, collected by Net Survey in 2013 as part of the Civil Hydrography Programme (CHP) surveys managed by the Maritime and Coastguard Agency (MCA) for the UK Hydrographic Office; and (ii) the North St George’s Channel candidate Marine Conservation Zone (rMCZ) survey, collected jointly by JNCC and Cefas in 2012 for the Department for Environment, Food and Rural Affairs (Defra). MBES backscatter, physical samples (e.g. grabs, cores, and boreholes), academic papers and previous BGS geological interpretations at broader scales (250k and 50k scales) were used to further inform this geological interpretation. The bedrock is divided into three units: (i) Neoproterozoic to Palaeozoic age metamudstones and metasandstones of the Monian Supergroup; (ii) undifferentiated Lower Palaeozoic age rocks (mudstone, volcaniclastics, siltstone, slate); and (iii) limestone and sandstone of the Carboniferous Limestone Supergroup. The superficial deposits are composed of various types of glacial sediments (e.g. glacial till and morainic deposits) that were deposited underneath and around the margins of the last British-Irish Ice Sheet in the area, and also more recently deposited marine sediments.

  • Geochemical data for the upper 300cm of giant piston core MD04-2832. Core MD04-2832 was collected from the middle basin of Loch Sunart a fjord on the west coast of Scotland from the research vessel Marion Dufresne on the 15th of June 2004. This data resource includes five data sheets: (1) Geochemical data, (2) Bulk radiocarbon, (3) ICP-MS, (4) FRUITS and (5) Age Model. 1. Geochemical data sheet includes Bulk elemental data (Organic Carbon, Nitrogen, C/N ratio, N/C ratio), Isotopic data (δ13C and ẟ15N), Biomarker data (Alkanes, Fatty Acids, GDGT's) and thermosgravimetric data (% labile, recalcitrant and refractory organic matter). 2. Bulk Radiocarbon data sheet includes bulk radiocarbon data for ten sediment samples presented as % modern, 14C Age (years BP), ẟ14C and Δ14C. 3. ICP-MS data sheet includes metal data associated with mining activities within the fjords catchment. Data includes Zinc (Zn), Lead (Pb), Copper (Cu), Barium (Ba), Aluminium (Al) and elemental ratios of these metal normalized with Al concentrations. 4. The FRUITS data sheet contains the outputs from the FRUITS Bayesian isotopic mixing model (Fernandes et al., 2014) used to constrain the source (terrestrial vs marine) of the organic carbon found at site MD04-2832. The model used bulk elemental ratios (N/C), Isotopic (δ13C and ẟ15N) and biomarker data (GDGT - BIT Index) to calculate the terrestrial and marine OC fraction from each downcore sample. 5. The Age Model datasheet contains the age model produced by the BACON software package (Blaauw and Christen, 2011). The age model was developed with a combination of shell/foraminifera radiocarbon dates and radiometric dating (210Pb and 137Cs). Further details on the data can be found in Smeaton, C., Cui, X., Bianchi, T.S., Cage, A.G., Howe J.A., Austin, W.E.N., (2021), The evolution of a coastal carbon store over the last millennium, Quaternary Science Reviews.

  • The Marine Photographs Archive held by BGS includes photographs of hydrocarbon well and (non-hydrocarbon) marine boreholes, cores and other samples. There are also photographs of the seabed and survey operations. The photos are primarily for the UKCS (United Kingdom Continental Shelf) and surrounding areas and date from the 1970s onwards. The photographs, which are a mix of prints, negatives and digital are applicable to a wide range of uses including environmental, geotechnical and geological studies. There are also some x-rays of cores.

  • The 3D multi channel seismic data were acquired as part of a collaborative investigation into models of magmatic segmentation between the Scripps Institute of Oceanography and BIRPS (the British Institutions Reflection Profiling Syndicate). The 3D EPR (East Pacific Rise) ARAD (Anatomy of a Ridge Axis Discontinuity) EW9707 cruise was undertaken in September and October 1997 to provide both refelction and wide-angle seismic data for the study of the overlapping spreading centre (OSC) at 9 degrees 3 minutes N on the East Pacific Rise. The data were acquired with a single source and a single streamer with a nominal line spacing of 100 m. The 3D-EPR ARAD survey was a joint NERC/NSF (US National Science Foundation) funded project and the copyright for this survey is held jointly. Reference: Bazin, S. Harding, AJ. et al. (2001) Three-dimensional shallow crustal emplacement at the 9 degree 03 minute N overlapping spreading center on the East Pacific Rise, Journal of Geophysical Research.