Geophysical Investigations of the Cattewater Wreck 1997-2007 (original) (raw)
Related papers
The Cattewater Wreck Licensee's Report 2013
2013
The remains of the Cattewater wreck are completely buried beneath the seabed in the Cattewater, Plymouth, with no part of the wreck visible on the seabed to indicate its position. The precise location of the hull is currently unknown as is the actual depth of burial below current seabed level. As the location is unknown and the hull cannot be reliably detected by conventional remote sensing, how much of the hull still survives is a mystery. The position of the hull remains may be inferred from a number of different sources of information but none are definitive and all suffer from a significant degree of uncertainty. This document collates the information currently available and defines a current best estimate for the position and burial depth of the hull. The only associated feature visible on the flat mud seabed that covers the Cattewater wreck is the top of a vertical steel scaffold pole. This pole was originally thought to be a long upright ‘leg’ from the scaffold grid frame that was set up for the main site excavation. However this may not be the case. This report provides no background information about the Cattewater wreck or the work done previously on the site but this information can be found in the referenced documents and in the Redknap 1984 report in particular. The results of the recent sub-bottom profiler surveys over the site have also been omitted from this report as the data from these surveys has to be reprocessed in the light of conclusions from this document. The results of this work will be published in due course. The annual report also suggests further work that could be done on the site to avoid losing the hull again once it has been relocated. It is interesting to note that this is the second time this site has been lost; the first was after the initial investigation when the site was first found; the team took a year to relocate the site as again it was buried with few clues visible on the seabed (Bax 1976).
Journal of Archaeological Science, 2002
Between 1998 and 2000, a series of geophysical surveys were conducted over the site of La Surveillante, a French Frigate wrecked in 1797 in Bantry Bay, Co. Cork, Ireland. The objectives of the surveys were to accurately relocate the wreck-site, delineate the extent of site, map the seafloor and subsurface lithologies in the wreck-environs and provide basemaps for more detailed diver investigations. The integrated surveys employed a suite of equipment consisting of a digital echo-sounder, side-scan sonar, Chirp sub-bottom profiler and an Overhauser-effect magnetometer. Integration and interpretation of the geophysical data indicate La Surveillante was wrecked on a fine-grained substrate in a low energy environment, with site distribution limited to an area measuring 50 25 m centred on the wreck. Integration of geophysical-and diver-survey data, with tidal and sediment records, indicates site formation is dominated by biological and chemical processes.
This paper presents the way conventional marine geophysical methods may be used with the highest efficiency for deep-water archaeological research, especially for the detection of ancient shipwrecks. Their use becomes all the more effective, when the principles of oceanography and marine geology are being followed during the interpretation of the geophysical recordings. The integration of sub-bottom profiling data provides valuable information on the geological structure of the seafloor's shallow substrate, which are an almost absolute prerequisite for a geologically reasonable interpretation of the side scan sonar images. Otherwise, interpretation of the sonar recordings may be erroneous or may be in direct discrepancy with the shallow sub-seafloor geological structure. Limitations of the efficiency of the geophysical methods in the case of targets of biogenic or anthropogenic origin or in shallow water environments are also being discussed.
Proceedings of the Open University Geological Society, Vol. 1, 23-33. ISSN: 2058-5209
Detailed and accurate mapping of the marine environment is important for a number of stakeholder groups, including energy companies (oil and gas, and, increasingly, offshore renewables), policy groups who require environmental data for marine spatial planning, resource and conservation management, and academic researchers who aim to better understand the processes that initially formed, and continue to shape these environments. Since the 1960s both industry and researchers alike have undertaken systematic exploration of the UK offshore territory (e.g. Gatliff et al. 1994; Johnson et al. 1993; Ritchie et al. 2011 and references therein). More than 11,000 industry exploration and production wells, and 580 scientific boreholes have been acquired in UK waters. Other physical sampling techniques such as Shipek Grabs that sample the seabed sediments, vibrocorers, gravity corers, piston corers and rock corers total more than 45,000 samples in the territorial waters of the United Kingdom (U...