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doi:10.2204/iodp.proc.314315316.216.2012

Sampling and preparation

Before being sent to the onshore laboratory for further investigations, samples were shaped onboard the D/V Chikyu into ~20 mm thick cubes with a parallel diamond blade saw and measured for electrical conductivity and APV. In most cases, the orientation convention used for paleomagnetism was followed: +z points downcore along the core axis, +x points into the working half, and +y is perpendicular to the z-axis within the core face. Once received, samples were measured for magnetic remanence in order to allow azimuthal reorientation, were left at room temperature for several days, and then were shaped into polyhedrons before being measured for AMS and APV. Polyhedrons with 14 facets were prepared to allow P-wave velocity measurement in seven independent directions, as opposed to three directions in the original cubes. The seven directions measured consist of the three reference directions plus four diagonals (Fig. F2). For numerous reasons from recovery issues to orientation, drying, and preparation of the facets, a significant number of samples had to be discarded, and not all units cored are represented in this study. Our data set comprises 262 samples for AMS and 185 samples for APV. Individual counts per site for both measurements are given in Figure F1.

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