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Mandatory Fields
Thesis/Dissertation
Kozachenko, M.
2005
Present and Past Environments of the Belgica Mounds (deep-water coral carbonate mounds), Eastern Porcupine Seabight, NE Atlantic.
Author
Published
1
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Optional Fields
corals NE Atlantic Seabed Mapping Marine Geology Side-scan sonar Underwater video Survey Cold water Carbonate mounds

This thesis demonstrates a multidisciplinary approach to the study of deep-water coral reef ecosystems on the Atlantic European margin. It is concerned with the assessment of remotely sensed geophysical data, in conjunction with ground truthing ROV video surveys, sediment core analysis and subsequent GIS data integration. These techniques have been applied to assess the current state of deep-water coral reefs and also provide insights into the history of their development. This work was undertaken through detailed investigation of the Belgica Mounds (deep-water coral carbonate mounds rising up to 200m above seabed) in the eastern Porcupine Seabight, North East Atlantic. Additional data, from the western Porcupine Bank (Pelagia Mounds) and the northern Rockall Trough (Darwin Mounds), are also presented in order to provide a regional context. 

 The GIS integration of all the datasets showed that the Belgica mound province is strongly affected by the northerly bottom water current flows (with speeds up to 1.5m/sec) and associated drift sedimentation. The province can be subdivided into two belts: the eastern mound belt containing mainly retired forms, in terms of biological coral growth, and the western belt containing active (coral colonised) mounds. The assessment of sedimentary processes and water mass properties suggests that the mound retirement resulted from changes in oceanographic characteristics of the Mediterranean Outflow Water and the onset of contourite drift deposition (with sedimentation rates c.6-100cm/ka) during Quaternary. Palaeoenvironmental reconstructions show that climate changes played an important role in the development of the Belgica Mounds, with average mound growth rates of c.10cm/ka during interglacials and c.5.8cm/ka during glacials. Examination of particle size data show a regional pattern of temporal variations in the strength of bottom currents, suggesting that the province underwent six peak current events during MIS (Marine Isotope Stage) 2-4. Evidence indicates that the mounds began development c.1.8-2 million years ago. 

 This study provides a generalised model for the formation of the carbonate mounds. It defines seven stages in mound development and discusses factors imperative for the initiation, development and sustainability of the mounds. 

University College Cork
1
550
Grant Details