Figure F21. Preliminary pressure data collected in the Expedition 301 CORK deployed in Hole 1026B and the previously existing CORK in Hole 1027C. Hole 1026B data were recorded using the new pressure monitoring systems (Fig. F20) deployed in September 2004. A. Pressure record during time when instruments were carried from the elevator to the CORK in Hole 1026B and connections were made to the valves on the CORK head. B. Detail of pressure record showing general quality of the data. C. Detail of end of initial record, indicating the presence of excess pressure (relative to hydrostatic) in Hole 1026B. As described in the text, this excess pressure comprises a combination of natural overpressure and additional thermal buoyancy in the borehole induced during seepage before the valves were closed. D. Evidence that the upper oceanic crust is hydrogeologically "connected" from Site U1301 to Site 1027, 2.4 km away. Rig pumping records from Site U1301 and pressure data downloaded from the CORK system in Hole 1027C. Pressure record has been corrected for tidal loading. There is a clear correlation between pumping in basement in Holes U1301A and U1301B and the pressure response in Hole 1027C. Several particularly abrupt "events" are marked with red arrows. ROV = remotely operated vehicle. JD = Julian day.
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