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A seismic refraction line across Norfolk

Published online by Cambridge University Press:  01 May 2009

P. N. Chroston
P. N. Chroston
Affiliation:
School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K.
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Abstract

A simple seismic refraction line some 115 km long has been made across Norfolk to provide constraints on the depth to the ‘igneous/metamorphic’ basement. Shots were fired in the Wash and off the coast near Lowestoft and attempts were made to record at approximately 2 km intervals along the line. Recording quality was only fair, resulting in incomplete coverage of the line, and this restricts the quality of interpretation. The results show a refractor of about 6.05 km s−1 revealed over the whole line with no first-arrival evidence of the 4.5–5.5 km s−1 velocity expected from Palaeozoic sediments. Using estimated velocities of 2.4 km s−1 for the post-Palaeozoic succession, 4.5–5.5 km s−1 for the Palaeozoic succession and an estimated sub-crop position of the basement on the sub-Mesozoic floor, models are produced which suggest that the Palaeozoic sediments are no more than 600–1500 m thick at the eastern end of the line, depending on the Palaeozoic velocity assumed.

Type
Articles
Information
Geological Magazine , Volume 122 , Issue 4 , July 1985 , pp. 397 - 401
Copyright
Copyright © Cambridge University Press 1985

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