2003 Strategic Environmental Assessment SEA4 Technical report - Seafloor sediments and sediment processes on the outer continental shelf, continental slope and basin floor (north UKCS)

This report is a contribution to the Strategic Environmental Assessment (SEA4) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). The report describes the surficial sediments in the SEA4 area and the sedimentary processes that are active in the area at the present day. The report focuses on the deeper water areas from the outer continental shelf to the floor of the Norwegian Basin in the northernmost part of SEA4. The report is based on sidescan sonar images, multibeam bathymetry, sub-bottom profiles, seabed photographs and sediment samples. The Holocene and late glacial events and processes that contributed to the present day seafloor morphology and sediment distribution are reviewed, as is the present day oceanographic regime. It is concluded that the present day sedimentary environment, seaward of the continental shelf edge at about 200 m water depth, is dominated by low sediment input and deposition rates, and by reworking of surficial sediments by bottom currents. The large scale seabed morphology was shaped mainly during the last glacial, when high sediment input resulted in glacigenic debris fan formation.

Simple

Date (Publication)
2003-01-01
Citation identifier
British Geological Survey / BGS_SEA_49
Point of contact
Organisation name Individual name Electronic mail address Role

British Geological Survey (BGS)

Paul Henni

offshoredata@bgs.ac.uk

Custodian

Department for Energy and Climate Change (DECC)

enquiries@decc.gsi.gov.uk

Originator
Maintenance and update frequency
Not planned
Resource format
Name Version

Documents
Keywords

SeaDataNet Parameter Discovery Vocabulary

GEMET - INSPIRE themes, version 1.0

  • Geology

SeaVoX Vertical Co-ordinate Coverages
Use limitation

The SEAs data were produced as part of the UK Department of Energy and Climate Change's Offshore Energy Strategic Environmental Assessment programme; Crown Copyright, all rights reserved. The DECC SEA must be acknowledged in any maps or publications that make use of the data. All the data files are freely available to the public. The Strategic Environmental Assessment (SEA) data portal provides free access to available data and reports which have been produced through the SEA process. The site is run and managed by BGS on behalf of the Department of Energy and Climate Change (DECC). Many files can be downloaded directly from this website. Those that are too large to download can be ordered via the website for postal delivery from BGS. BGS (NERC) has been contracted by DECC to publish SEA datasets on its behalf. All intellectual property rights (including , without limitation, copyrights, database rights and all other rights which subsist or may at any time in the future subsist in the Dataset(s)) in the Dataset(s) ('Intellectual Property Rights') are owned by DECC (formerly the Department of Trade and Industry, and the Department for Business, Enterprise and Regulatory Reform). BGS has been authorised by DECC to use SEA datasets for all purposes but on a 'not-for-profit basis'. BGS has been authorised by DECC to pass on SEA datasets to third parties so that they can use them for all purposes but on a 'not-for-profit' basis.

Access constraints
Intellectual property rights
Distance
5  m
Language
English
Topic category
  • Environment
  • Geoscientific information
  • Oceans
Title

SeaVoX salt and fresh water body gazetteer
Date (Revision)
2006-01-01
Code
North Atlantic Ocean
N
S
E
W
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Begin date
1996-01-01
End date
2002-01-01
Supplemental Information

http://www.offshore-sea.org.uk/site/index.php

Reference system identifier
OGP / urn:ogc:def:crs:EPSG::4326
Distribution format
    OnLine resource
    Protocol Linkage Name
    http://www.bgs.ac.uk/data/sea/home.html

    Strategic Environmental Assessment (SEA) data portal
    Hierarchy level
    Dataset
    Statement

    This report was prepared by Dr D G Masson and colleagues from the Southampton Oceanography Centre as part of the UK Department of Energy and Climate Change's Offshore Energy Strategic Environmental Assessment programme. Survey data used in this report includes sidescan sonar images, multibeam bathymetry, subbottom profiles, seabed photographs and sediment samples. This data was collected during a number of surveys funded by the Atlantic Frontier Environmental Network (AFEN) in 1996 and 1998 and by the DTI in 1999, 2000 and 2002. Sidescan sonar data was collected using two systems, the 30 kHz TOBI system in water depths greater than 200 m and a 100 kHz ORE or Widescan system at depths shallower than 200 m. The TOBI instrument package included 30 kHz sidescan sonar, 7.5 kHz profiler, three axis fluxgate magnetometer, CTD and an ultra-short baseline navigation transponder beacon. Sub-bottom profiles were collected using the 7.5 kHz profiler mounted on TOBI and a 3.5 kHz surface towed profiler. Seabed photography was carried out using the SOC WASP system, an off bottom towed camera. Three different sampling devices were used to cope with the wide range of surface sediment types, ranging from coarse gravel to mud, found in the SEA4 area. In fine grained sediments, a hydraulically damped multiple corer with up to twelve 10 cm internal diameter core tubes was used to obtain high quality cores up to 30 cm in length. In coarser sediments, particularly where significant quantities of gravel were present, this was replaced with a USNEL-type box corer capable of collecting a square section sample of 0.25"m2 and up to 50 cm in length. In very coarse sandy gravels, where other sampling devices failed, a Day grab was used as a last resort.

    Metadata

    File identifier
    aba64100-c126-4de3-e044-0003ba6f30bd XML
    Metadata language
    English
    Hierarchy level
    Dataset
    Date stamp
    2011-08-30
    Metadata standard name

    MEDIN Discovery Metadata Standard
    Metadata standard version

    Version 2.3.5
    Metadata author
    Organisation name Individual name Electronic mail address Role

    British Geological Survey (BGS)

    Mary Mowat

    offshoredata@bgs.ac.uk

    		Point of contact
     
     

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