Paull Fluid Flow Cruise
October 2 - October 8, 2000
October 3, 2000: Day #2
Charlie Paull writes: Tiburon descended into the center of the canyon at 2700 meters. After taking two thermal gradient measurements, we began a transect across the axis of the canyon to the canyon wall taking push core samples along the way. The canyon bottom was a typical sequence of mud over fine sand. The transect continued parallel to the canyon wall along a scarp, which consisted of approximately one meter of fine sediment overlying a 1-2 meter layer of angular cobbles of granite. Granite is not known to outcrop in this area. This appears to be a massive turbidite deposite, exhumed by subsequent canyon floor erosion.
Heading upslope from 2717 meters to 2536 meters, we traversed canyon fill deposits. From 2538 meters to 2052 meters, we sampled horizontally bedded sedimentary rocks. From 2052 meters to 1693 meters, the sediment-covered seafloor lacked obvious outcrops. Push cores from this area suggest firm clays in the immediate subsurface. No chemosynthetic communities were observed.