Wessex Archaeology (WSX) Geophysical Survey WESSEX3B: (23/Aug/2006 to 23/Aug/2006)
Wessex Archaeology was commissioned by Historic Scotland to undertake an Undesignated Site Assessment of the site known as the Tobermory Galleon in Tobermory Bay, Mull. The work was undertaken as part of the Contract for Archaeological Services in Relation to the Protection of Wrecks Act (1973). The assessment was carried out in advance of possible further commercial salvage work on the site. Wessex Archaeology conducted a geophysical survey at three sites within Tobermoray Harbour on the 23rd August 2006. The survey was conducted from the S/V Xplorer. A geophysical survey was followed by diver ground-truthing of anomalies was carried out to confirm the position, extent, stability and character of any significant archaeological deposits. The survey showed that part of the wreck and debris fields from both the sinking and subsequent salvage may still exist although the precise nature, extent and position of archaeological deposits associated with the wreck, in particular any surviving coherent ship structure, remained unclear. The survey included single beam echosounder, sub-bottom profiler and sidescan sonar. The geology and geophysics component of the data are archived at British Geological Survey (BGS) MEDIN Data Archive Centre (DAC) for Geology and Geophysics. Data were also provided to other archive centres as appropriate.
dataset
BGS Offshore Geoindex
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British Geological Survey
:
BGS_CMD_REF655
English
Geoscientific information
GEMET - INSPIRE themes, version 1.0:
SeaVoX Vertical Co-ordinate Coverages (L131):
SeaDataNet Parameter Discovery Vocabulary (P021):
Free:
-6.0712,
56.6135,
-6.0477,
56.6279
Tiree, Minches & Western Scotland, INNER SEAS OFF THE WEST COAST OF SCOTLAND
publication: 2006-08-23
2006-08-23
-
2006-08-23
grid
British Geological Survey (BGS)
The Lyell Centre, Research Avenue South,
Edinburgh,
EH14 4AP,
UK
tel: +44 (0)131 667 1000
email:
enquiries@bgs.ac.uk
Role: custodian
Wessex Archaeology
email:
offshoredata@bgs.ac.uk
Role: originator
Data Quality
Geophysical equipment types used included: CHIRP Sub-bottom Profiler, Echo Sounder and Sidescan Sonar. The survey was undertaken by Wessex Archaeology. Throughout the survey all co-ordinates were expressed in WGS84, UTM zone 29N. Single beam bathymetric data were recorded throughout all stages of surveying and was acquired using a Knudsen 320M single beam echo sounder. The echo-sounder transducer was mounted to the survey vessel, and the transducer draught was measured and entered into the echo sounder to obtain depths relative to the sea-surface. A TSS DMS 2.05 motion sensor was rigidly mounted above the transducer to measure the vertical displacement (heave) and attitude (roll/pitch) of the vessel; this data was interfaced with the echo sounder. The accuracy of the draught and velocity offsets were checked at the start of the survey using the bar check method. Sub-bottom profiler data were acquired using a chirp system. The chirp system used was the new EdgeTech 3100P portable sub-bottom profiling system using a SB-126S tow vehicle. The chirp is a high resolution wideband frequency modulated sub-bottom profiler. The system transmits a frequency modulated pulse that is swept over a full spectrum frequency range (in this case 2-12 kHz). The vertical resolution using 2 – 12 kHz frequency is 8cm and in an area of silts and clays, which is typical for the survey areas of concern, the typical sub-seabed penetration is expected to be up in excess of 10m. Sidescan sonar data were acquired using a Klein 3000 dual frequency towfish. This system collects data at 125kHz and 445kHz simultaneously. The Klein 3000 collects data at both high and low frequencies and therefore produces high quality images suitable for archaeological purposes. High and low frequency data were acquired at a range of 75m throughout the survey. Due to the number of moorings and moored vessels in the harbour navigating along planned survey lines was not always possible. However, full coverage of sidescan sonar data was ensured by acquiring sidescan sonar data at a smaller line spacing and running infill lines where necessary.
Minimal Distance:
5 urn:ogc:def:uom:EPSG::9001
INSPIRE Implementing rules laying down technical arrangements for the interoperability and harmonisation of unknown theme
Constraints
The copyright of materials derived from the British Geological Survey's work is vested in the Natural Environment Research Council [NERC]. No part of this work may be reproduced or transmitted in any form or by any means, or stored in a retrieval system of any nature, without the prior permission of the copyright holder, via the BGS Intellectual Property Rights Manager. Use by customers of information provided by the BGS, is at the customer's own risk. In view of the disparate sources of information at BGS's disposal, including such material donated to BGS, that BGS accepts in good faith as being accurate, the Natural Environment Research Council (NERC) gives no warranty, expressed or implied, as to the quality or accuracy of the information supplied, or to the information's suitability for any use. NERC/BGS accepts no liability whatever in respect of loss, damage, injury or other occurence however caused.
Metadata about metadata
c5bc60cd-04e9-3862-e044-0003ba9b0d97
British Geological Survey (BGS)
The Lyell Centre, Research Avenue South,
Edinburgh,
EH14 4AP,
UK
tel: +44 (0)131 667 1000
email:
enquiries@bgs.ac.uk
Role: point of contact
2024-04-24