23. PHYSICAL PROPERTIES DATA AT HOLE 959D: COMPARISON OF CORE AND LOG MEASUREMENTS AND A PROPOSED REVISION OF LITHOLOGIC UNITS¹

A.G. Janik,² J.A. Hood,² and M.V. Ask³

ABSTRACT

A revised division of lithologic units is proposed for Hole 959D in the interval from 400 to 1000 meters below seafloor from Ocean Drilling Program Leg 159 based on combining the geophysical and sedimentological information. This new division is essential for further geological studies of the Cote d’Ivoire-Ghana Transform Margin area. A comparison is made between shipboard laboratory measurements made on core samples and in situ downhole logging data. Logging data, in conjunction with physical properties data, provide a more detailed record of the variation in the sediment column, which enables a more qualitative assessment of lithotype distribution. Emphasis is placed on distinguishing between the lithologic factors influencing the geophysical signals and artifacts resulting from imperfect data collection. Good overall agreement between core and log data for rotary core barrel cored sediments at Hole 959D is observed, and effects of core expansion caused by the removal of overburden pressure do not appear significant.

¹Mascle, J., Lohmann, G.P., and Moullade, M. (Eds.), 1998. Proc. ODP, Sci. Results, 159: College Station, TX (Ocean Drilling Program).
²Division of Marine Geology and Geophysics, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149-1098, U.S.A. ajanik@rsmas.miami.edu
³Engineering Geology, Royal Institute of Technology, S-100 44 Stockholm, Sweden.