After a 314-nmi voyage at an average speed of 10.7 kt, the vessel proceeded directly to the Global Positioning System coordinates of the site, where a beacon was deployed at 0407 hr on 7 September. Hole 1080A was spudded at 1020 hr on 7 September. The seafloor depth was established at 2765.8 meters below sea level (mbsl) by drill-pipe measurement (DPM). APC coring advanced to 50.8 mbsf (Table 1; also see the expanded core summary table on CD-ROM, back pocket, this volume), which was considered APC refusal when an attempt at the seventh piston core resulted in no advance because of contact with a very hard layer. Cores were oriented starting with Core 175-1080A-4H. The hole was then deepened with the XCB from 50.8 to 52.1 mbsf, with high torque and very little penetration. After 20 min of rotation, the core barrel was recovered containing 0.12 m of dolomite, and the hole was terminated. The bit cleared the seafloor at 1730 hr on 7 September.
The vessel was offset 40 m to the south, and Hole 1080B was spudded with the APC at 1845 hr. The seafloor depth was established at 2767.9 mbsl by DPM. APC coring advanced to 37.7 mbsf. When the attempt at Core 175-1080B-5H resulted in no advance of the core barrel because of a hard sediment layer, an XCB core barrel was dropped (5X) and advanced 0.5 m in 25 min of rotation. The decision was made to terminate the site, and the drill string was pulled back to 2767.0 m, clearing the seafloor at 0025 hr on 8 September. The hydrophones and thrusters were retracted, and the drilling equipment was secured for transit by 0600 hr, thereby ending operations at Site 1080.