|
< December | February >
IODP Expedition 345
Hess Deep Plutonic Crust
Daily Science Report for 31 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Today, we RCB cored continuously from 45.6 to 73 mbsf. Cores U1415P-11R to ‑16R obtained 8.46 m of medium-coarse grained gabbroic rocks from this 27.5 m interval (31% recovery).
Daily Science Report for 30 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Today, we RCB cored continuously from 18.1 to 45.6 mbsf. Cores U1415P-5R to ‑10R obtained 12.19 m of medium to coarse grained gabbroic rocks from this 27.5 m interval (44% recovery).
Daily Science Report for 29 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Today, we obtained 5.27 m of coarse-grained gabbroic rocks. Core U1415P-2G (2.36 m recovery) was obtained while drilling down to the bottom of Hole U1415P (12.5 mbsf) to start RCB coring. Core U1415P-3R was cut from 12.5 to 18.1 mbsf and recovered 1.29 m (23%). Core U1415P-4G, our last core of the day, recovered 1.62 m of rock while drilling back down to the bottom of the hole. The last six hours of the day we spent cutting the next core below 18.1 mbsf.
Daily Science Report for 28 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: The 14.75 inch tri-cone bit arrived back on the rig floor at 0130 h. We assembled 12.5 m of 10.75 inch casing, hung it off on the moon pool doors, and then lowered the RCB coring bottom hole assembly and camera system to the seafloor. We positioned over Hole U1415P and observed that the free fall funnel (FFF) we deployed was not upright. After a failed attempt to enter Hole U1415P through the FFF cone, the bit was positioned over the hole near the base of the titled FFF cone and we successfully reentered the hole. Once we cleaned out 2 m of fill on the bottom, we dropped a FFF with 12.5 m of casing into the hole. At the end of the day, we deployed the camera to inspect the FFF cone and casing.
Daily Science Report for 27 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: At 1345 h, the 14.75 inch tri-cone bit had reached 12.5 mbsf in Hole U1415P. We decided not to drill any deeper without coring and prepared to deploy a free-fall funnel (FFF) with 10.75 inch casing to facilitate reentry. We conducted a short wiper trip that indicated good hole conditions and then deployed the camera to observe the bit being pulled out of the hole. The FFF cone was almost entirely obscured by mud coming out of the hole. The rest of the day was spent retrieving the drill string. Our plan is to install 12.5 m of 10.75 inch and then RCB below the casing.
Daily Science Report for 26 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: At the start of the day, our 14.75 inch bit was at 3 mbsf in Hole U1415O. Drilling was progressing very slow and consistently to ~5 mbsf. At that depth, the “bottom dropped out” and the bit penetrated from 10–15 mbsf in only 15 minutes. From ~15 mbsf, the next two meters drilled hard and consistently again so we prepared to deploy a free-fall cone (FFF) cone. However, hole conditions started deteriorating (even as far up at the hard formation at 5 mbsf) and we decided to abandon Hole U1415O. After pulling the bit out of the hole (0710 h), we deployed the camera, conducted a visual inspection of the seafloor, and started drilling with the 14.75 inch bit at Hole U1415P (~50 m west of Hole U1415O). At midnight, the bit had reached 5.5 mbsf.
Daily Science Report for 25 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: At 0200 h, the RCB bit from Hole U1415N arrived back on the rig floor. Our next step was to disassemble the 26 m of 10.75 inch casing that had been previously hung off in the moon pool for deployment at Hole U1415M. We assembled a 14.75 inch tri-cone bit and lowered it to the seafloor along with the camera system. We conducted a 2.75 h visual and 3.5 kHz sub-bottom survey of the seafloor to identify our next drill site. Drilling in Hole U1415O started at 1900 h and had reached 3 mbsf by midnight. Our plan is to drill a 14.75 inch hole, deploy a free-fall funnel cone, renter with a RCB coring bit, deploy 10.75 inch casing to stabilize the uppermost seafloor, and RCB below there.
Daily Science Report for 24 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Today we recovered Cores U1415N-3R and -4R. These were cut from 18.9 to 37.0 mbsf and recovered 0.96 m (5%) of olivine-phyric basalt and gabbro. After recovering Core U1415N-4R at 1320 h, we spent the next four hours attempting to get back to the bottom of the hole. At 1700 h, we decided to abandon Hole U1415N due to deteriorating borehole conditions and poor recovery. We spent the rest of the day recovering the drill string and at midnight the bit was 914 m below the rig floor.
Daily Science Report for 23 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: After abandoning Hole U1415M, we offset the ship 15 m to the west and started RCB coring in Hole U1415N at 0340 h. Cores U1415N-1R and -2R extended from 0 to 18.9 mbsf and recovered 0.6 m (3%) of olivine-phyric basalt. The evening was spent washing and reaming back down to the bottom of the hole. We began cutting Core U1415N-3R just before midnight.
Daily Science Report for 22 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: At 0330 h, we recovered the 14.75 inch bit on the rig floor after having drilled to 25.9 mbsf in Hole U1415M. After assembling 26 m of 10.75 inch casing and hanging it off on the moon pool doors, we lowered a RCB coring bottom hole assembly through the casing and to the seafloor. By mid afternoon, we were positioning to reenter Hole U1415M. The free-fall funnel (FFF) cone appeared to shift when the bit touched down in it. Although the bit clearly went through the opening in the bottom of the FFF, it did not enter the hole below. After several hours of attempting to rotate the bit to the hole below, at midnight we decided to abandon Hole U1415M.
Daily Science Report for 21 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: By noon, the 14.75 inch bit reached 25.9 mbsf in Hole U1415M. After washing and reaming the hole from 8 to 24 mbsf, we deployed the camera to observe the seafloor around the hole, the bit being withdrawn from from the hole (1602 h), and the FFF cone after pulling out to assess suitability for subsequent reentry. Although the FFF cone had settled into the seafloor and was mostly obscured by the cuttings pile and mud emanating from the hole, it appears to be properly set. We started retrieving the drill string and by midnight the bit was at 1979 mbrf. We are going to change to a RCB coring bottom hole assembly, reenter the hole, and deploy 26 m of 10.75 inch casing to stabilize the uppermost section to allow deeper RCB coring.
Daily Science Report for 20 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Early in the morning, we reached the seafloor with the 14.75 inch tri-cone bit and the camera system. After releasing a seafloor positioning beacon from the camera system, we conducted a short visual survey of the seafloor ~95 m east of Hole U1415K. This included verifying seafloor depth at several positions with the bit that indicated a slope of ~14°. We then conducted a short jet-in test (Hole U1415L) to determine near surface characteristics for a free-fall funnel (FFF) cone. The bit reached 4 mbsf and we used the camera to inspect the seafloor during and after the bit was pulled above the seafloor. At 1240 h, we started Hole U1415M. When the bit was at 11 mbsf, we deployed a FFF cone and then continued drilling deeper, reaching 19.6 mbsf by the end of the day. This 14.75 inch hole is intended for installing 10.75 inch casing to stabilize the uppermost section to allow deeper RCB coring.
Daily Science Report for 19 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: We conducted a camera survey around the Hole U1415K FFF cone that was tilted on its side to search for cuttings pile or other indications of the hole, but found none. We attempted to reenter Hole U1415K by placing the bit at the base of the FFF cone but were unable to successfully reenter the hole. We decided to abandon Hole U1415K so we spent the rest of the day retrieving the RCB bit and preparing to start a new hole with a 14.75 inch tri-cone bit. At midnight, the 14.75 inch bit was had reached a little over 2700 m below the rig floor.
Daily Science Report for 18 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: We used the camera system to inspect the free-fall funnel (FFF) cone we deployed yesterday. Unfortunately we observed it was not upright as intended but tilted substantially to one side. We decided to retrieve the 14.75 inch tri-cone bit, change to an RCB bit, and attempt to locate and reenter the FFF/hole. At the end of the day, the bit was back near bottom and we were conducting a camera survey around the FFF.
Daily Science Report for 17 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Today, we continued deepening Hole U1415J with a 14.75 inch tri-cone bit. We reached a total depth of 35.2 mbsf at 1600 h and then spent the next 5 h washing and reaming to stabilize the hole in preparation for casing installation. We dropped a free-fall funnel (FFF) cone without a stinger at 2200 h and then pulled out of the hole. At the end of the day, we were lowering the camera system to inspect the FFF. Our next step will be to reenter the hole to RCB core, deploy another FFF with 10.75 inch casing to stabilize the uppermost hole, and then RCB deeper.
Daily Science Report for 16 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Hole U1415J ended at 0130 h, when the bit arrived back on the rig floor. We offset the ship ~500 m to the Northwest, lowered the drill string with a 14.75 inch tri-cone bit to the seafloor, and conducted a short visual survey to identify where we want to locate Hole U1415K. At 2155 h, we started drilling (without coring) in Hole U1415K. At midnight, we had reached 5.6 mbsf. Our plan is to drill to ~15 mbsf and then deploy a free-fall funnel (FFF) cone to facilitate reentry, reenter to RCB core, deploy another FFF with 10.75 inch casing to stabilize the uppermost hole, and then RCB deeper.
Daily Science Report for 15 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: After we finished washing and reaming back to the bottom of the hole (103.8 mbsf), we retrieved the core barrel that was in place (Core U1415J-25G; 0.48 m recovery), dropped a new core barrel, and resumed RCB coring. We cut Core U1415J-26R from 103.8 to 111.8 mbsf and it returned with 0.78 m of gabbroic rocks. The penetration rate for the first ~4 m of that interval was 1.3 m/h. However, the last 3.8 m drilled in only 3 min. As we recovered this last core on the rig floor (0830 h), the pipe became stuck. After 6.5 h of working the pipe and attempting to release the bit, the pipe became unstuck at 1500 h. We pulled the bit clear of the seafloor at 1535 h and spent the rest of the day retrieving the drill string. We have decided to terminate operations in Hole U1415J.
Daily Science Report for 14 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: The majority of the day was spent lowering the drill string to the seafloor to drill out the cement and resume RCB coring in Hole U1415J. We reentered Hole U1415J at 1542 h. After the camera system was recovered, we lowered the bit down the hole. The bit first encountered resistance at 26 mbsf and we washed and reamed down to 78 mbsf where we encountered the top of the cement. The day finished with the drill bit at the base of the cement at 99 mbsf (the bit was at 93 m when we pumped the cement). We will resume RCB coring after drilling back down to the bottom of the hole (103.8 mbsf).
Daily Science Report for 13 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: After retrieving the core barrel that was in place while washing and reaming the hole (Core U1415J-22G with 0.07 m recovery), we continued having difficulty getting back to the bottom of the hole. So we conducted a wiper trip between 74.0 and 101.8 mbsf. Then, a single RCB core was cut from 101.8 to 103.8 mbsf that recovered 0.53 m of gabbroic rocks (Core U1415J-23R). We continued having trouble getting back to the bottom of the hole after recovering the core barrel. In addition, pump pressures had increased suggesting that some of the bit jets might have been clogged. We decided to cement a 20 m interval near the bottom of the hole (~73 to 93 mbsf). After pumping the cement, we raised the bit up to 15 mbsf (inside the casing) and circulated it clean. We pulled the bit out of the hole (1605 h) and spent the rest of the day retrieving the drill string.
Daily Science Report for 12 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: We finished drilling back down to the bottom of Hole U1415J, recovered the core barrel (Core U1415J-17G; containing 0.12 m of gabbroic rocks), and resumed RCB coring from 84.4 mbsf. Cores U1415J-18R to -21R were taken from 84.4 to 101.8 mbsf (17.4 m) and recovered 3.85 m of gabbroic rocks (22%). We had to spend time after recovering Cores U1415J-19R and -21R (1015 h to 1200 h; after 2115 h) conducting short wiper trips and washing/reaming the hole to maintain hole conditions.
Daily Science Report for 11 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: After preparing Hole U1415J for further RCB coring (two cement jobs and multiple wiper trips), we spent the majority of today assembling an RCB bottom-hole assembly and lowering it to the seafloor. We reentered Hole U1415J at 1700 h and lowered the bit to ~35 mbsf before it encountered any resistance (this has been a problem interval). We washed and reamed from there and had reached 82.5 mbsf by midnight (~7 m above the bottom of the hole).
Daily Science Report for 10 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: We reentered Hole U1415J and left the bit in the casing until 0630 h to allow the cement to fully harden. We drilled out the cement (63 to 73 mbsf), washed and reamed back down the bottom of the hole, deepened the hole without coring from 79.4 to 84.4 mbsf, and conducted a wiper trip. At the end of the day, we had pulled out of the hole so that we can change out the bottom-hole assembly and return to RCB coring. Scientists met to discuss initial results from Hole U1415J.
Daily Science Report for 9 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: We spent the early morning washing and reaming to ~2 m above the total depth of Hole U1415J. After circulating mud, we raised the bit up to 14 mbsf and paused for 30 minutes before lowering the bit back down. We had to drill from 35 to 76 mbsf. We placed the bit at 63 mbsf and started pumping 35 barrels of cement (more than two times the borehole volume). As the cement was being pumped, we lowered the bit to 71 mbsf. We raised the bit up to 14 mbsf and circulated the 10.75 inch casing and FFF clear of any excess cement. We pulled out of the hole, circulated the pipe to clear any remaining cement. Since we had to wait for the cement to harden, we used the time to conduct a seafloor survey of potential future drill sties. At 2215 h, we reentered Hole U1415J and retrieved the camera system.
Daily Science Report for 8 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: We re-entered Hole U1415J with a 9.975 inch tri-cone bit at 1130 h. We lowered the bit down to 47 mbsf without encountering any of the cement that we pumped yesterday when the bit was at ~49 mbsf. The tri-cone bit encountered fill at 57 mbsf and we spent the rest of the day washing and reaming to 71 mbsf (total depth of the hole is 79.4 mbsf). Scientists attended a presentation on the magma hydrothermal transition in fast spread crust.
Daily Science Report for 7 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: We finished cleaning out the hole in preparation for cementing to stabilize problematic intervals in the hole (e.g., 37–47 mbsf). After recovering the core barrel that was in place during washing and reaming (Core U1415G-15G; recovered 0.64 m of gabbroic rocks), we pumped cement with the bit at 57 mbsf. Our target is to cement from there up to ~20 mbsf. We raised the bit up to 15 mbsf and circulated the 10.75 inch casing and FFF clear of any excess cement. We pulled out of the hole, circulated the pipe to clear any remaining cement and spent the rest of the day was spent recovering the drill string. The bit arrived on the rig floor just before midnight.
Daily Science Report for 6 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Today we recovered Cores U1415J-12R and -13R. These extended from 69.7 to 79.4 mbsf and recovered 1.33 m of gabbroic rocks (14% recovery). After encountering some hole problems when recovering Core U1415J-13R, we decided to conduct a wiper trip. The bit was easily raised up to 6.5 mbsf. When lowering the bit back down, hole problems were first encountered at 37 mbsf that we were able to wash and ream past. We had to wash and ream continuously from 57 mbsf to the bottom of the hole. It appears that we have ~23 m of cuttings that we have not been able to circulate out of the hole. Once on bottom, the pipe became stuck (no rotation, unable to raise/lower bit, high pump pressure), but we were able to free the drill string after ~2 h. Once the pipe was free and the hole circulated clean, the bit was raised back up to 6 mbsf. We recovered Core U1415J-14G that recovered 0.15 m of gabbroic rocks. We lowered the camera system to observe the vertical placement of the upper “nested” free fall funnel with 15 m of 10.75 inch casing. We needed to do this to estimate the amount of cement we will use to stabilize the hole and help improve our chances of getting cuttings out of the hole. The top of the FFF appeared to be only ~2–3 m above the seafloor. At the end of the day we started washing and reaming back to the bottom of the hole to prepare for pumping cement.
Daily Science Report for 5 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Today started with washing and reaming Hole U1415J, primarily between 29.0 and 34.9 mbsf. Before resuming RCB coring, we retrieved the core barrel (Core U1415J-7G) that contained 1.54 m of cored gabbroic rocks. RCB coring continued for the rest of the day. Cores U1415J-8R to 11R were cut from 34.0 to 69.7 mbsf and returned 5.12 m of gabbroic rocks (15% recovery).
Daily Science Report for 4 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: We continued RCB coring in Hole U1415J. Core U1415J-5R arrived at 0650 h in the morning. It extended from 26.2 to 34.9 mbsf and recovered 1.88 m of gabbroic rocks (22% recovery). After recovering Core 5R, we spent the rest of the day working back to the bottom of the hole with particular difficulty from ~28 to 32 mbsf. After lunch we recovered a core (Core U1415J-6G) from this previously drilled interval that recovered 0.33 m of gabbroic rocks. The rest of the day was spent washing and reaming the hole so that we can continue coring deeper.
Daily Science Report for 3 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: The day started by locating and reentering Hole U1415J at 0420 h. After we recovered the camera system, we assembled a free-fall funnel (FFF) cone on top of the 15 m of 10.75 inch casing that was hung off in the moon pool. After we released this novel FFF system at 0730 h, we spent the rest of the morning washing and reaming back to the bottom of the hole. We recovered the core barrel, Core U1415J-2G, that arrived back on deck with 0.2 m of small pieces of gabbroic rocks and a large amount of sand (cuttings?). We then started RCB coring and cut Cores U1415J-3R and -4R from 15.0 to 26.2 mbsf. These recovered 0.86 m of gabbroic rocks (8% recovery). At the end of the day, we started cutting Core U1415J-5R. Scientists met today to share initial results from the first few holes.
Daily Science Report for 2 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: The first part of our day was spent finalizing our hole cleaning operations in Hole U1415J. After the 14.75 inch bit was worked back to bottom at 15 mbsf, we pulled out of the hole and the bit was back on the rig floor at 1400 h. We hung off 15 m of 10.75 inch casing in the moon pool, assembled an RCB coring BHA, and lowered it through the casing in the moon pool. At the end of the day, the bit was approaching the seafloor, the camera deployed, and we were preparing to reenter Hole U1415J. After re-entering, we plan to check hole conditions, attach a FFF cone to the casing in the moon pool, and free-fall it into the hole.
Daily Science Report for 1 January 2013
LOCATION: Site U1415 (HD-01B), Hess Deep
SCIENCE UPDATE: Today was spent drilling Hole U1415J with a 14.75 inch tri-cone bit. After penetrating to 15 mbsf, we conducted several wiper trips and the hole appeared to be stable and in good condition. We then deployed a free-fall funnel (FFF; without a stinger below) to aid in finding and reentering the hole. Before we deployed the camera system to monitor pulling the bit through the FFF and out of the hole, borehole conditions deteriorated. The drill string encountered an obstruction at 7.8 mbsf and we spent the rest of the day working the bit back toward the bottom of the hole. At the end of the day, we had worked the bit down to nearly 9.9 mbsf.
| 