IODP NanTroSEIZE Stage 1:
Expedition 315: NanTroSEIZE "Megasplay Riser Pilot"
Weekly Report #1
Date 23/Nov/2007
Expedition 315 started on 16 November. After one day maintenance for drilling equipments, pre-spud meeting was held on 18th and description and routine measurements were done for Hole B cores (taken in the Expedition 314).Started RIH in the evening of November 19th.
Observed HPCS core barrel was broken during running with core line at 1515 m water depth, due to strong vibration caused by Kuroshio current. Fishing operation succeeded in the early morning of 20th, restarted running again to the seafloor and spud-in the Hole E.
13 cores were taken by HPCS until morning of 21st. Downhole temperature measurement was carried out by APCT3 for every third core from the Core 2H. After shooting the 14th core, inner barrel parted at bottom of 2nd rod connection. Abandoned the Hole E, moved 20 m east and spud-in the Hole F. Wash down to 108 meters below the seafloor (mbsf) and started coring with about 10 m of overlap with the previous hole. Core liner busted in the Core Cutting Area on Hole F Core 10H probably due to high gassy sediments. Co-chiefs, EPM, Lab Officer and OSI discussed about safer procedures: 1) punctuation on a liner in advance to coring, 2) cover a liner around the place to cut by half-round plastic pipe while cutting. Drilled to 220.3 mbsf and took 17 cores by HPCS. Downhole measurement with APCT3 was performed on Cores 2H, 5H and 8H.
Total 31 cores have been routinely described, measured and sampled by Science Party since 20th. Routine measurement subjects are:
Whole-round (WR) sampling for interstitial water at Core Cutting Area, CT-scan, WR sampling for microbiology, MSCL and thermal conductivity for WR core, WR sampling for other purposes (geotechnical, structural), Visual description, Image scanning, Colorimetry, Magnetic property, Moisture and density, Shear strength (Vane shear / penetrometer), XRD, Microfossil age determination (nanno, foraminifer) and Sampling for element analyses (total / inorganic C, N, S).
In the evening of 22nd, seemed to reach to the base of the slope sediments, which is the first major tectono-lithostratigraphic boundary defined by seismic profile. Downhole temperature measurement with APCT3 was carried out at total 7 depths down to 179 mbsf, and yielded good temperature gradient.
