During this expedition we will maintain a log of information relayed from the chief Scientist on the expedition.  Whenever possible, images will be displayed along with the text.

April 27 - Day 11 - Status Report

27 April 2005 - On Location Atwater Valley Block 13 - Coring

Location: On location Atwater Valley Block 13#2

Science Update: Coring activity picked up yesterday, with four cores recovered between 1600 and 2000 hrs. Two nonpressurized (4H and 6H) cores were processed, sampled and logged. Two pressurized cores (5R and 7P) successfully recovered sediment, but were only partially successful in retaining pressure. The valve on the Hyacinth rotary core (5R) did not close properly. The Fugro rotary core retained subsurface pressure, but could not be successfully transferred. Adjustments are being made and both tools are expected to function properly in future deployments. The nonpressureized (FHPC) cores (4H and 6H) contained abundant gas with numerous expansion gaps in the core liner, but no observable evidence of gas hydrate or no cold spots when imaged by IR. Gas samples from the cores were analyzed and contained relatively pure methane (99%) with increasing amounts of ethane (up to 180 ppm). These ethane levels are greater than would be expected in microbial methane at such shallow depths (36 mbsf), and probably indicate some input of migrated thermogenic gas.

Plans: Coring was interrupted just before midnight by an electrical malfunction in the top drive, which is not expected to be repaired until after 1700 hrs today. When we resume coring we will take one more FHPC core to a depth of about 44 mbsf, and then wash down without coring to a depth of 117 mbsf. The depth interval between 117 and 153 mbsf contains the most interesting indications of possible gas hydrate occurrence at this location, both from the seismic records and the Logging While Drilling (LWD) data.

Planning and Data Sheet for AT13 - #2   [PDF-10KB] 
Includes Scientific objectives for these drill sites

Photos:
Day 10 Photo Gallery  - Pressurized core prior to transfer to lab and seabed frame preparation
Day 6 Photo Gallery - Working with push cores and ROV photos of sample collection at AT 14
Day 4 Photo Gallery - Remotely Operated Vehicle (ROV), Sampling, Core Handling
Day 3 Photo Gallery - Preparation for Drilling
Day 2 Photo Gallery Loading the Uncle John [PowerPoint]
The drill ship out to sea - Setting up the lab [PowerPoint]