We drilled Holes 1190A, 1190B, and 1190C (see Fig. F1 in the "Site 1189" chapter) with the aim of intersecting volcanic rocks below an area devoid of evidence of recent hydrothermal activity. Drilling reached no farther than 17.2 meters below seafloor (mbsf) and produced only 110 cm of core. Almost all the rocks recovered are fresh, black, glassy, moderately vesicular, plagioclase-clinopyroxene ± magnetite phyric rhyodacite (70% SiO2 on an anhydrous basis). Some samples are slightly altered, with evidence of incipient bleaching of the glassy volcanic groundmass. Most pieces exhibit rare, hairline siliceous (±clay) veinlets. The rocks recovered from Site 1190 are similar to those recovered at our other sites from the same depths. Thus, it is not possible to conclude whether or not intense alteration is present at shallow depths at Site 1190, as is the case in all of the other sites drilled, especially the nearby Roman Ruins high-temperature site.
The original objectives for Site 1190 were to obtain information on the volcanic architecture of Pual Ridge and to collect fresh material for comparison with the rocks recovered at other sites. Additionally, results obtained earlier in Leg 193 suggested that hydrothermal alteration may be more intense and widespread than previously thought. Consequently, we also wanted to test the possibility that below a few tens of meters of fresh or incipiently altered rocks lie deeply altered counterparts even at this background site. However, because of the technical and logistics difficulties (see below), we were not able to fully address either of these objectives, though the issue of volcanic architecture was effectively addressed by other holes drilled during Leg 193.
Upon completion of operations at Hole 1189A, we assembled a new rotary core barrel (RCB) bottom-hole assembly (BHA), and the ship was offset ~200 m in dynamic positioning mode to our third primary target, Site 1190 (Table T1). A brief seafloor survey with the subsea camera system preceded a jet-in test that resulted in no penetration. Hole 1190A was then spudded at 0300 hr on 24 November 2000, at a seafloor depth measured by drill pipe length at 1714.0 meters below rig floor (mbrf). The vibration-isolated television (VIT) was recovered, and RCB coring commenced at 0345 hr.
Core 193-1190A-1R was the only material recovered from this hole, cored to a depth of 9.1 mbsf. Recovery was a few small pieces (0.03 m). The drill string stuck while picking up off bottom at a depth of 6.0 mbsf. No rotation was possible; however, the pipe was pulled free with 200 klb of overpull. The bit cleared the seafloor at 0530 hr on 24 November 2000, ending Hole 1190A.
After deploying the subsea camera and conducting a brief survey, Hole 1190B was spudded at 0750 hr. The seafloor depth measured by drill pipe length was 1712.0 mbrf. Once again, the hole was limited to a single RCB core. Total penetration for the hole was 10.1 mbsf, of which the first 1.5 m was jetted in without rotation. The total cored interval for Core 193-1190B-1R was 8.6 m, and recovery totaled 0.24 m, or 2.8%. Tight hole conditions were encountered at a depth of 1720.0 mbrf, or 8.0 mbsf. The pipe was pulled free with 25 klb of overpull. The VIT was deployed, and we saw the bit pulling clear of the seafloor at 1105 hr on 24 November 2000, ending Hole 1190B.
With the camera still deployed, we conducted yet another seafloor survey to find another potential drilling location. Hole 1190C was spudded at 1215 hr at a seafloor depth of 1707.0 mbrf. Once the VIT was recovered, continuous RCB coring was initiated. Cores 193-1190C-1R through 3R were cut to a depth of 1724.2 mbrf (17.2 mbsf). Drilling in this hole was the hardest and slowest of all the holes spudded so far on this cruise. While cutting Core 193-1190C-3R, the driller noted an increase in drilling torque and pump pressure with a rapid increase in rate of penetration. We suspected that the drilling circulation was going into the formation rather than up the hole annulus and out at the seafloor. The subsea TV camera was deployed to verify if drill cuttings were getting back to the seafloor while the sandline was deployed to recover the last 4.0 m of RCB core. Seafloor observations confirmed that no returns were reaching the surface, and the VIT was recovered back to the ship. While retrieving Core 193-1190C-3R, the aft core line parted at ~577 m. Fortunately, the loose end hung up in the top drive, preventing a time-consuming fishing ordeal. T-bar clamps were used to remove the parted core line, and an additional 300 m of badly corroded line was removed. The drill string was pulled clear of the seafloor at 2400 hr and cleared the rig floor at 0520 hr on 25 November 2000, ending Hole 1190C.
The short survey (0240-0256 hr, 24 November 2000) was on target and did not extend far enough to sight the two markers laid at this site. No new beacon was deployed. Initially, the pipe tagged bottom on the lower side of a ledgelike lava outcrop with several rocks visible. A jet-in test here showed hard bottom. The pipe was then moved a few meters south, climbing onto the flat, lightly sediment-covered upper surface of the ledge, apparently a sheet flow as anticipated from the precruise site surveys. Hole 1190A was spudded on this spot.
After lowering the camera at Site 1190A without sighting a hole or the site markers, a short 20-m traverse (0720-0753 hr, 24 November 2001) to the southeast (along the presumed isobath) was conducted. This crossed moderately thick sediment cover on a gently sloping surface with occasional exposed rocks and hummocks over buried rocks. A jet-in test experienced hard bottom after blowing away a few centimeters of sediment, so the hole was spudded at this site.
The VIT was lowered with the pipe still inserted at Hole 1190B. After extracting the pipe, we moved along three sides of a rectangle before spudding (1048-1225 hr, 24 November 2001). The track passed over scattered rocks on a sedimented surface, initially 50 m southeast, while climbing 7 m gradually, then 25 m northeast descending 6 m, then 20 m northwest climbing 5 m up a lava ledge. Hole 1190C was spudded in sediment between two small rocks after a jet-in test penetrated only 1 m.
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