Three holes were cored at Site 1007: 1007A, 1007B, and 1007C. Onboard samples for magnetic studies were collected continuously in 7-cm3 cubes at Hole 1007B at ~20-cm intervals in the top six cores (above 57.5 meters below seafloor [mbsf]). The sampling interval mainly consists of nannofossil ooze and variably lithified wackestone to packstone. Nannofossil ooze lithofacies dominate above 10.9 mbsf in the section. Grainstone to packstone lithofacies measuring several tens of centimeters and apparently formed by turbidity currents also appear in this interval. Each of these turbidites is marked by a sharp basal contact that is overlain by bioclastic coarse grains fining upward into wackestone. The interval from 10.9 to 43.5 mbsf consists of a sequence of nannofossil ooze that grades downhole into unlithified mudstone and wackestone. In the upper part, light olive-brown silty peloidal wackestone alternates with white nannofossil ooze. In the lower part, unlithified to partially lithified bioclastic wackestone alternates with gray-colored clay and silt-rich unlithified mudstone. Below 43.5 mbsf, unlithified peloidal wackestone lithofacies dominate.
The remanent magnetization of discrete samples was measured using a 2G Enterprises model 760 superconducting pass-through magnetometer. Stepwise alternating field (AF) demagnetization was performed to examine the stability of the remanent magnetization. Subsequently, an anhysteretic remanent magnetization (ARM) was imparted by an AF of 100 mT superimposed on a direct-current field of 0.05 mT. We examined AF demagnetization of this ARM, together with isothermal remanent magnetization (IRM) acquisition and AF demagnetization. Magnetic susceptibility was also measured with a KappaBridge KLY-3S magnetic susceptibility meter.
After measuring magnetic properties, each sample was processed by a smear-slide preparation method for calcareous nannofossil study. The microslide was observed under binocular polarizing.