A. Cramp,2 S.V. Lee,2 J. Herniman,2 R.N. Hiscott,3 P.L. Manley,4 D.J.W. Piper,5
M. Deptuck,5 S.K. Johnston,5 and K.S. Black6


It is known that variation can exist in grain-size data generated from automated sizing equipment currently in use; this is especially true for natural sediments, particularly for fine-grained marine muds. Over 98% of the sedimentary material recovered during Leg 155 consisted of fine-grained marine sediments, and since three shore-based laboratories have carried out the majority of the fine-grain-size analyses produced to date, it was deemed essential to carry out and present information on both analytical procedures and the sizing equipment used at each of the laboratories. This report presents interlaboratory comparisons carried out on identical samples using the Micromeritics SediGraph, the Coulter Counter, and the Coulter Laser system.

Results of the interlaboratory comparisons carried out on size data generated from two Micromeritics SediGraph machines are in reasonable agreement, though it is noted that high levels of dispersant concentration appear to produce biased data, especially within the very fine fraction. In addition, around 6 f (16 Ám), there are significant differences between the data generated using the SediGraph as compared with the Laser and Coulter Counter systems. These deviations are attributed to the different techniques adopted by each piece of analytical equipment in determining grain size, and are in general agreement with similar studies that have compared the various sizing techniques. Over 600 grain-size analyses are presented (in CD-ROM format) for subsamples of fine-grained material recovered from sites along the Upper Levee Complex and the Amazon Channel of the Amazon Fan.

1Flood, R.D., Piper, D.J.W., Klaus, A., and Peterson, L.C. (Eds.), 1997. Proc. ODP, Sci. Results, 155: College Station, TX (Ocean Drilling Program).
2Marine and Environmental Geosciences Research Group, Department of Earth Sciences, University of Wales Cardiff, Cardiff CF1 3YE, United Kingdom. cramp@cardiff.ac.uk
3Department of Geology, Memorial University, St. Johns, Newfoundland, Canada.
4Department of Geology, Middlebury College, Middlebury, Vermont 05753, U.S.A.
5Atlantic Geoscience Centre, Geological Survey of Canada (Atlantic), Bedford Institute of Oceanography, P.O. Box 1006, Dartmouth, Nova Scotia B2Y 4A2, Canada.
6Gatty Marine Laboratory, St. Andrews University, St. Andrews, Scotland, United Kingdom.

See Publisher's Note for correct authorship.