Analysis and Interpretation of X-Ray Images of Sediment Cores from Hole 910D, Yermak Plateau: Preliminary Results

Abstract

Ocean Drilling Program Hole 910D was drilled on the crest of the southern Yermak Plateau at 80°15.881'N, 6°65.424'E, in 567.7 m water depth. This hole consists of three cores recovered with the advanced hydraulic piston corer (APC) and 15 cores recovered with the extended core barrel (XCB), penetrating to a total depth of 160.6 meters below sea floor (mbsf). Three earlier holes were drilled at this site, but two of them (Holes 910A and 910B) failed to penetrate through a stiff horizon at about 20-24 mbsf, and a third hole (Hole 9IOC), drilled using the rotary core barrel (RCB), yielded poor core recovery in the upper 200 mbsf. As a first step in the study of individual core sections from Hole 910D, non-destructive, whole-core X-ray examinations were performed at the Atlantic Geoscience Center of the Bedford Institute of Oceanography in Dartmouth, Nova Scotia, Canada. Using a high-resolution video monitor, X-ray images of almost 96 m of core were visually examined and described; these X-ray images were simultaneously recorded on video tape for further digital processing and interpretation. Videotaped X-ray images of the Hole 910D core sections have been used to identify the relative position and size of individual clasts (>2 mm in diameter) and coarse sand layers, and to identify extensively bioturbated intervals, represented by burrow traces in these cores. Solid particles >2 mm in diameter, were counted for successive 10-cm intervals of core using the video X-ray images. The X-ray images provide "ground truth" for making comparisons with other nondestructive measurements made on these cores using sensors mounted on the multisensor track (MST), and for identifying changes in depositional environments at this site.