SITE 1035

Hole 1035A (Proposed Site BH-3)

The ship was moved in DP mode to Hole 1035A at 48°26.020'N, 128° 40.920'W about 73 m west of Hole 856H. The beacon (S/N 1256) from Hole 856H could not be turned back on and a new beacon (S/N 614) was dropped. An APC/XCB/MDCB BHA was run as follows: 11-7/16" Security S86F 4-cone core bit (S/N 478459), LBS w/ LFV, SBDC,LSS, LTS, MHS, 10' DCS, MDCB latch sub, 5 X 8-1/4" DC, tapered DC, 6 jts 5-1/2"transition DP, crossover, and 5" DP. Hole 1035A was spudded at 0600 hr on 8 September. The seafloor was at 2456.4 mbrf. APC Cores 1035A-1H to 6H were taken from 0 to 55.0 m with 100% recovery in clays and sulfide sands and breccias. The last two cores were partial strokes with 20-40K lb overpull, and the liner was shattered on the last core, prompting a change to the XCB system. XCB Cores 169-1035A-7X to 19X were taken from 55.0 to 170.8 m with 55.6% recovery in clays and sulfides. Five of 13 cores jammed in the core catcher, and the XCB hard formation shoe was destroyed on the last core. A decision was made to return to Hole 857D to finish the cleanout and CORK installation. The bit cleared the rotary table at 2100 hr on 9 September. Beacon S/N 1256 was recovered and beacon S/N614 was turned off.

Return to Hole 857D

The ship was moved in DP mode back to Hole 857D while tripping pipe. The beacon (S/N 1253) was turned back on. A 9-7/8" RBI CC-7 core bit (S/N BK317) was run with a FV, BS, OCB, TS, HS, 4 DC, TDC, 2 stands 5-1/2" DP, XO. Hole 857D was reentered at 2200 hr on 9 September, and the bit was run in to 22 m. Silt stirred up in the water was being sucked down the hole, confirming that the hole was still taking water. A sinker bar was run in to 642 m, and an external temperature tab indicated the maximum temperature was less than 108°C. Drill pipe was run in to 377 m, where an obstruction was noted. The hole was washed and reamed from 359 to 446 m against generally light resistance using 5K lb wob. The pipe was run in to 621 m, and a WSTP water sample was taken. The temperature was 2°C, and the sample proved to be seawater, which confirmed a strong down flow to that depth. The hole was washed and reamed against light resistance from 611 to 929 m (3360 mbrf or 8 m above TD).

Left in Hole 857D are one 2-1/2" by 2-m-long 270-lb thermistor sinker bar and 4 each 1/2" X 3" long wireline spear prongs. A decision was made not to deepen the hole due to time constraints and a questionable long term weather forecast. Hole conditions appeared to be stable with occasional light resistance and minor ledges noted. The bit cleared the rotary at 2000 hr on 10 September and had anhydrite on the teeth and spiral stabilizer blades. The CORK assembly consisted of: stinger of 3 junk knobby joints, XO, CORK assembly (11-3/4" stretch version), CORK running tool, S. Sub, 5 DC, TDC, 2 std 5-1/2"DP, XO. Hole 857D was reentered at 0200 hr on 11 September. A 2-1/2" by 2-m-long 270-lb sinker bar, 898 m of 5/8" braided kevlar thermistor string with 9 thermistors, and a data logger were run on CWL, latched into the CORK, and test pulled to 15K lb. The ROV platform was dropped at 0845 hr. The installation was checked with the TV, and the CORK was released at 1000 hr. The running tool cleared the rotary at 1445 hr on 11 September.

Hole 1035B (Proposed Site BH-7)

The ship was moved in DP mode to Hole 1035B about 51 m south of the Bent Hill massive sulfide deposit. The same APC/XCB/MDCB BHA was run without a monel DC. Hole 1035B was spudded at 2130 hr on 11 September. Core 169-1035B-1H was a partial stroke in a hard layer near the seafloor, and the core barrel could not be pulled. The TV revealed that the core barrel was bent at ~90°. The pipe was pulled, and a small sample of mud was taken for paleontological reference from the bent core barrel and archived as Core 169-1035B-1H. The bit cleared the rotary at 0530 hr on 12 September.

Hole 1035C (Proposed Site BH-7)

The ship was not moved because hard massive sulfides at the seafloor were assumed to be the cause of the APC refusal on Hole 1035B. The VIT-TV was run because of the bent core barrel and an unclear seafloor indication on the PDR (2465.4-2469.4 mbrf), and the seafloor was found at 2459.0 mbrf. Hole 1035C was spudded at 1215 hr on 12 September. The XCB coring system was used for spudding because of the hard surface. XCB Cores 169-1035C-1X to 5X were taken from 0 to 44.0 m (2503.0 mbrf) with 4.8% recovery. Core 169-1035C-4X had some torque and a mud sweep was circulated. On Core 169-1035C-5X, there was 7 m of fill on the connection and the torque increased despite circulating another mud sweep. The pipe was pulled because the hole was unstable and caving in. The bit cleared the seafloor at 2050 hr on 12 September. A strobe light was noted on the surface about 1 nmi northwest of the ship. As soon as the bit cleared the seafloor, the ship gave chase on the assumption that one or both of the PUPPIs had released prematurely. Beacon 774 was recovered and had released for unknown reasons from near Hole 858G on Dead Dog mound.

Hole 1035D (Proposed Site BH-2)

The ship was moved in DP mode to Hole 1035D on the east side of the Bent Hill massive sulfide deposit about 73 m east of Hole 856H. The water depth was 2459.8 mbrf. Hole 1035D was spudded at 0100 hr on 13 September. APC Cores 169-1035D-1H to 5H were taken from 0 to 40.6 m (2500.4 mbrf) with 110.5% recovery. Core 169-1035D-5H was a partial stroke that penetrated no more than 7.0 m (the bit hit a hard layer) and had at least 2 m of suck-in for a 9.91-m apparent recovery. XCB Cores 169-1035D-6X to 7X were taken from 40.6 to 57.7 m with 2.9% recovery. Recovery was very poor in the black sulfide powder matrix with massive pyrite nodules. Broken sulfides, anhydrite, and pyrite nodules jammed in the core catchers. Massive sulfides with anhydrite cementation were cored successfully at TAG using the MDCB system, and anhydrite cementation was increasing; therefore, the MDCB system was run in an attempt to improve recovery. The hole was drilled with an XCB shoe and center bit from 57.7 to 59.3 m, and a mud sweep was circulated to clean the hole. The MDCB was run with standard thruster and bit nozzles, 5K lb wob, and no DP rotation, circulating 38 spm (190 gpm) at 1225-1200 psi. Core 169-1035D-8N was taken from 59.3 to 60.8 m (1.5 m stroke per paint marks on the core barrel) in 15 min. with 0.09 m (6.0%) recovery. The piece of massive sulfide and pyrite indicated rotation in the core catcher. XCB coring was resumed with Cores 169-1035D-9X to 24X from 60.8 to 178.5 m (2638.3 mbrf) with 5.0% recovery. Recovery was poor because 13 of 18 XCB cores jammed in the XCB shoe throat and core catcher. Operations were terminated when the objective of the hard layer at about 170 mbsf was reached.

Hole 1035E (Prospectus Site BH7)

The ship was moved in DP mode to the next location at Hole 1035E (site BH) about 100 m south of Hole 856H. The water depth was 2465.0 mbrf. APC Cores 169-1035E-1H to 5H were taken from 0 to 45.5 m (2510.5 mbrf) with 104.8% recovery. Core 169-1035E-5H was a partial stroke that bounced back and wrapped the coring wireline (CWL) around the sinker bars. The CWL then parted at 12K lb overpull when attempting to pull it, and the BHA was pulled.

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