The 64-nmi voyage from Site 1075 to Site 1076 was accomplished at an average speed of 11.4 kt. As the vessel slowly approached the location using Global Positioning System coordinates, the beacon was deployed at 2338 hr on 26 August. Hole 1076A was spudded at 0440 hr on 27 August. The seafloor depth was established at 1404.2 meters below sea level (mbsl) by drill-pipe measurement (DPM). APC Cores 175-1076-1H through 22H were taken from 0 to 204.3 mbsf (Table 1; also see expanded core summary table on CD-ROM, back pocket, this volume), with 204.3 m cored and 217.5 m recovered (106.3% recovery). Cores were oriented starting with 3H. The Adara heat-flow shoe was deployed at Cores 3H (23.8 mbsf), 5H (42.8 mbsf), 8H (71.3 mbsf), and 11H (99.8 mbsf). Headspace analysis of the cores indicates the presence of biogenic methane with minute amounts of ethane (<28 ppm) and no discernible amounts of heavier hydrocarbons. The methane concentration peaked at 66 mbsf (69,000 ppm) and gradually tapered off with depth. Although some of the cores exuded a mild sulphurous smell, concentrations of hydrogen sulfide were always <1 ppm and could not be measured. The drill string was pulled back with the bit clearing the seafloor at 1830 hr on 27 August, thereby ending Hole 1076A.
The vessel was offset 10 m to the east, and Hole 1076B was spudded at 1908 hr on 27 August. The seafloor depth was established at 1402.1 mbsl by DPM. After seven APC cores (0-60.9 mbsf), the hole was abandoned because virtually no sediment was recovered in Cores 175-1076B-5H, 6H, and 7H. The drill string was pulled out of the hole and cleared the seafloor at 2250 hr on 27 August, ending Hole 1076B.
The vessel was offset 20 m to the east, and Hole 1076C was spudded at 2325 hr on 27 August. APC Cores 175-1076C-1H through 22H were taken from 0 to 203.1 mbsf (Table 1), with 203.1 m cored and 216.8 m recovered (106.8% recovery). Cores were oriented starting with 4H. The drill string was pulled out of the hole with the bit clearing the seafloor at 1155 hr on 28 August.
The vessel was offset another 20 m to the east where the fourth and final hole of the site was spudded with the APC at 1230 hr on 28 August. The seafloor depth was established at 1401.0 mbsl by DPM. APC Cores 175-1076D-1H through 12H were taken from 0 to 113.5 mbsf (Table 1), with 113.5 m recovered (104.3%). The hole was aborted before the initial depth objective because of time constraints. The bit cleared the seafloor at 2030 hr on 28 August. While the drill string was being pulled out of the hole, the hydrophones and thrusters were retracted and secured, and the beacon was released and recovered at 2100 hr on 29 August, thereby ending operations at Site 1076.