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Title: A geophysical investigation of the physical properties of subduction accretion complexes
Author: Tiley, Graham John
ISNI:       0000 0004 2715 056X
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 1988
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Geophysical measurements were made, which map the 3-dimensional variation in seismic velocity and density of the sediments of the Barbados Ridge Complex, and indioate their state of compaction. Profiles of velocity with depth were obtained from ESP and sonobuoy data, by a number of methods, and lateral density changes within the complex were inferred from gravity modelling. Comparison of velocity results with reflection profiles provided evidence for north-south changes in arc crustal structure, and a well defined uppermost velocity layer in the complex was identified with recent slope sediment. The pattern of physical properties indicates a division between undercompacted sediment at the toe of the complex, and a more oompacted region arcward, and variations in the arcward gradient of compaction were suggested to reflect episodic growth of the complex. Comparison of velocity profiles with reference data was used to infer the compaction state of the forearc sediments, and undercompacted material in the deeper coaplex was identified with the underplating of subdue ted material. Compaction modelling was used to examine the development of pore pressures at the toe of the complex, and in the incoming sediments. Very high pore pressures in the underthrust sequence were shown to be likely, with contrastingly lower pressures in the accreted sediments. Published physical property data from other accretionary margins were also considered.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available