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.

May 4 - Day 18 - Status Report

4 May 2005 - Atwater Valley Block 14 - coring on mounds at AT14

Location: Atwater Valley Block 14 Mound Sites

Miriam Kastner, of the University of California at San Diego, prepares core samples for analyses on board the Uncle John

Science Update: The depth interval 0-29 mbsf was cored at mound site ATM1 (AT14#3 - 27°56'11.62”N, 89°16'46.09”W) with three Fugro Hydraulic Piston Corer (FHPC) cores and three Fugro Pressure Corer (FPC)or HYACE Rotary Corer (HRC) pressure cores. The FHPC cores recovered a total of 21 meters of sediment. The pressure cores in some cases recovered sediment, but did not retain subsurface pressure. The FHPC cores contained gas--relatively pure methane (98.6-99%) with traces of ethane (40-170 ppm) and minor CO2 (1-1.4%). The apparent gas content (based on core voids and pressure) was at a maximum in core ATM1-2H and declined with increasing depth in core ATM1-5H. Pore water removed from the core had salinity of 56 ppt in core ATM1-1H, which declined to 51.5 ppt in the upper part of core ATM1-2H, then increased back to 56 ppt at the bottom of core 5H. The salinity variation has the appearance of localized dilution by fresh water, which could be due to gas hydrate decomposition. Additional analyses are underway and planned to test this possibility.

Plans: Core upper 29 m at the second mound site ATM2 (AT14#4 - 27°56'11.60”N, 89°16'47.0”W), leave the Atwater Valley area by 23:00 on 5/5/05 and transit to Keathley Canyon.

A time-lapse digital camera assembly installed on the seafloor recorded hourly images of the growth or dissolution of an exposed hydrate deposit. These photos were taken during a research expedition to the northern Gulf of Mexico (Green Canyon 185, known as Bush Hill) in June of 2002.  This expedition was taken as part of a study to determine the potential impacts of gas hydrate instability in terms of the release of methane into seafloor sediments. DOE/NETL project DE-FC26-02NT41328

Planning and Data Sheet for AT14#3 (ATM1)   [PDF-10KB] 
Planning and Data Sheet for AT14#4 (ATM2)   [PDF-10KB] 
Includes Scientific objectives for these drill sites

Photos:
Day 16 Photo Gallery  - Photos by NETL scientist showing core analyses process and equipment
Day 12 Photo Gallery  - Photos by NETL scientist showing core retrieval and processing
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]