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 26 - Day 10 - Status Report

26 April 2005 - On Location Atwater Valley Block 13 - Core Processing

Location: On location Atwater Valley Block 13#2

Science Update: Due to mechanical problems with coring systems at AT13#2, only three cores were obtained and processed by 1400 hrs today. Next core should arrive by 1600 hrs. Core AT13#2 1H was a full 7 meter FHPC core with no gas expansion or obvious cold spots by IR. Each of the 1-m sections was sampled for pore water chemistry, and three of the sections sampled for headspace gas analysis. Preliminary results indicate that core 1H spans most of the sulfate reduction zone, with very faint H2S odor in the bottom section. Pore water salinity is that of normal seawater. Core AT13#2 -2H was an 8.5 m FHPC core with visible gas expansion voids near the bottom of the core. The gas was relatively pure methane (99%) with minor CO2 (1%) and ethane (<50 ppm) after correction for air contamination. MSCL logging of 1H shows P-wave velocity near 1500 m/s consistent with high porosity stiff clay. No major lithologic changes are evident in the MSCL logs. MSCL logging of core 2H was difficult for P-wave due to gas expansion cracks and voids. The third core was an FPC pressure core that overshot and prevented proper valve sealing at subsurface pressure. A full 1-m core was recovered as AT13#2-3P and will be processed as a regular non-pressurized core.

Plans: Continue with coring at AT13#2. Plan is to continuously core depth intervals 0-45m, 115-152m, 220-257m. Two more pressure cores will be deployed in the upper coring interval, and two each in the lower intervals for a total of seven. Five temperature measurements were planned, the first attempt at a depth of 15.5 mbsf was only partially successful. One piezoprobe measurement is planned deeper in the hole.

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]