ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

2aUW1. The investigation of millimeter scale heterogeneity in Coastal Benthic Boundary Layer sediments using microresistivity and x-ray imaging of ``diver'' cores.

Peter D. Jackson

British Geological Survey, Keyworth, Notts NG12 5GG, UK

Kevin B. Briggs

Naval Res. Lab., Stennis Space Center, MS 39529-5004

Robert Flint

British Geological Survey, Keyworth, Notts NG12 5GG, UK

Michael A. Lovell

Peter K. Harvey

Univ. of Leicester, Leicester LE1 7RH, UK

A micro-resistivity imaging technique, developed for use on 70-mm ``half-round'' slabbed core has been adapted for use with larger ``diver'' cores, 33 mm thick, 350 mm wide, and 440 mm long. This resistivity technique is shown to have a resolution of 5 mm and to operate in a manner which is complimentary to x-ray photography. Theoretical and practical examples are presented showing responses to individual heterogeneity such as shells. The benefits of 3-D investigations are explored via numerical models are shown to be beneficial even in cores such as those above having a ``flat'' aspect ratio. The microresistivity method is shown to be particularly sensitive to layered structures and the presence of shells within the very high porosity surface layers in Eckernforde Bay (89% porosity 0--10 cm below sea floor). [Work supported by U.S. Navy.]