IODP Expedition 336

Mid-Atlantic Ridge Microbiology

Daily Science Report for 31 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: Today we cored from 256.2 to 303.7 m (217.9 to 265.4 m below the sediment/basement interface). Cores 24R to 29R recovered 7.38 m of basalt (16%).

Daily Science Report for 30 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: Today we recovered 8.19 m of basalt from 211.6 to 266.2 m (173.3 to 227.9 m below the sediment/basement interface). We anticipate coring ~24 hr more before collecting downhole logs, conducting packer experiments, and installing a CORK observatory.

Daily Science Report for 29 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: As we assembled the new RCB bit and other parts of the bottom-hole assembly (BHA), we also repaired an air leak that had developed in a part of the heave compensator. The repair was completed at 0630 and we started lowering the bit to the seafloor. This will be our last coring trip before we proceed with downhole logging, packer experiments, and installing a CORK observatory.

Daily Science Report for 28 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: Today we took the last three cores with our first RCB bit. We recovered 2.8 m of basalt from 192.8 to 211.6 m (154.5 to 173.3 m below the sediment/basement interface). While taking these last three cores, a large long-period swell arrived. Eventually we decided to stop coring only 1 m into cutting the last core when large heave (~3 m) prevented us from being able to keep the bit on the bottom of the hole. We retrieved the drill string and bit; the bit was intact, but had loose roller cones. We are planning coring more with one last RCB bit before downhole logging, packer experiments, and installing a CORK observatory.

Daily Science Report for 27 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: We retrieved RCB Cores 11R to 15R from 153.5 to 192.8 m (154.5 m below the sediment/basement interface), and recovered 5.14 m of core (13%). Cores are variably altered, sparsely phyric basalt – some with glassy margins. Due to high torque, we pulled Core 15R after only 1 m of penetration to conduct a wiper trip. After cleaning out 20 m of fill on the bottom, we resumed RCB coring at the end of the day.

Daily Science Report for 26 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: We recovered RCB Cores 6R to 10R from 105.4 to 153.5 m and recovered 12.61 m (26%). Cores contain variably altered, sparsely phyric to plagioclase phyric basalts and a couple of pieces of highly lithified sediment. We plan to continue coring with this bit through tomorrow (27 October) when it will have accumulated ~50 rotating hours.

Daily Science Report for 25 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: We recovered RCB Cores 2R to 5R from 69.5 to 105.4 m and recovered 8.00 m (22%). The well-seasoned crew has retrieved basalt and peperite. The basalts are variably altered, sparsely phyric, and veined. A few pieces of highly lithified (baked) sediment were also recovered that include intermingled basaltic glass – appears to be peperite.

Daily Science Report for 24 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: Today we reentered Hole U1383C with an RCB bit and drilled out the cement at the bottom of the 10.75 inch casing. The cement extended 16.6 m up from the casing shoe and 4.4 m below it. At the end of the day, we started to retrieve the center bit so we could start coring.

Daily Science Report for 23 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: After the bit was recovered back on the rig floor (0700), the rest of the day was spent assembling, installing and cementing 10.75-inch casing 22.1 m into basement (60.41 mbsf). We released the casing running tool at 1940 h and started retrieving the drill string. Tomorrow, we'll start RCB coring of the oceanic crust below the casing shoe. Our current plan is to core as deeply as two RCB bits and the formation allow (~300 m?). Operations in Hole U1383C will conclude with downhole logging, hydrologic (packer) experiments, and installation of a multi-level CORK observatory for long-term coupled microbiological, biogeochemical, and hydrologic experiments.

Daily Science Report for 22 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: Today we finished drilling the hole for the 10.75-inch casing. This 14.75-inch hole reached 31.2 m into basement (69.5 mbsf). We conducted five wiper trips to clean and stabilize the hole before starting to pull out of the hole just before midnight. Our next step will be to install and cement ~60 m of 10.75-inch casing.

Daily Science Report for 21 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: The early part of today was spent recovering the drill string after installing a reentry cone and 16 inch casing extending to 34.8 mbsf. Next, we reentered with a 14.75 inch bit to prepare the hole for installing 10.75 inch casing into uppermost basement. After drilling only 3.5 m the bit encountered basement at 38.3 mbsf. Our current plan is to advance the 14.75 inch hole to ~70 mbsf (~32 m sub-basement) and run 10.75 inch casing to ~60 mbsf (~20 m sub-basement). Drilling is proceeding slowly as the top of the drill collars will remain above the seafloor.

Daily Science Report for 20 October 2011

LOCATION: Hole U1383C (NP-2; 22.8021°N, 46.0528°W, water depth 4425 mbrf)

SCIENCE UPDATE: We installed a reentry cone at Hole U1383C with 16 inch casing extending to 34.7 mbsf. Hole U1383C is located at the site of our original jet-in test and is 25 m southwest of Hole U1383B. Late in the day we began retrieving the drill string. Our next operation is to drill a 14.75 inch hole so we can install 10.75 inch casing into uppermost basement.

Daily Science Report for 19 October 2011

LOCATION: Hole U1383B (NP-2; 22.8022°N, 46.0526°W, water depth 4425 mbrf)

SCIENCE UPDATE: Today we continued deepening Hole U1383B to 89.9 m. The penetration rates had been rather slow (1.5 to 2.7 m/hr) and we started having hole problems and were not able to advance the hole any deeper. Even after conducting a wiper trip up to the 16 inch casing (at 54 m) and then back down to the bottom of the hole, drilling conditions did not improve. So, after a total of 5 hours without any improvement in drilling conditions or being able to advance the hole, we decided to recover the bit to inspect it. Unfortunately, the bit had completely lost two of its tri-cone cutting structures and the third had severe damage. We decided it was better to initiate a new hole rather than trying to salvage this one. At 1830, we started assembling a new reentry cone and 16 inch casing.

Daily Science Report for 18 October 2011

LOCATION: Hole U1383B (NP-2; 22.8022°N, 46.0526°W, water depth 4425 mbrf)

SCIENCE UPDATE: We reentered Hole U1383B with a 14.75 inch tri-cone bit to drill a hole for 10.75 inch casing. We lowered the bit it through the 16 inch casing that was installed to 54 mbsf (1 m into basement) and tagged cement 5 m up from the casing shoe - suggesting the cement job was successful. After drilling through the cement (which extended ~3 m below the base of the casing) and lowering the bit to the base of the 18.5 inch rat hole, we started drilling the 14.75 inch hole from 69 mbsf. The penetration rates are rather slow (1.5 to 2.7 m/hr) and by midnight we had reached 81.5 mbsf (~28.5 m into basement).

Daily Science Report for 17 October 2011

LOCATION: Hole U1383B (NP-2; 22.8022°N, 46.0526°W, water depth 4425 mbrf)

SCIENCE UPDATE: Today, we finished recovering the 58.7 m of 16 inch casing. We cut off 5 m and then were able to successfully cement it 1 m into basement in Hole U1383B. After releasing the casing running tool, we offset to circulate the drill string to flush out any remaining cement and then started to retrieve the drill string. Our next step will be to prepare the hole for 10.75 inch casing by drilling a 14.75 inch hole.

Daily Science Report for 16 October 2011

LOCATION: Hole U1383B (NP-2; 22.8022°N, 46.0526°W, water depth 4425 mbrf)

SCIENCE UPDATE: After drilling a hole to 68 mbsf (15 m into oceanic crust) with a 18.5-inch tri-cone bit, we attempted to install 58.7 m of 16 inch casing. Unfortunately, we were unable to lower the casing the final 3 m. At the end of the day, we started pulling the casing out of the hole. We intend to shorten the casing by 5 m (1 m into basement) and attempt installation again tomorrow.

Daily Science Report for 15 October 2011

LOCATION: Hole U1383B (NP-2; 22.8022°N, 46.0526°W, water depth 4425 mbrf)

SCIENCE UPDATE: After installing a re-entry cone and 20 inch casing to 34.7 m, we reentered Hole U1383B with an 18.5-inch tri-cone bit and drilled to 68 mbsf – 15 m into oceanic crust. We conducted multiple wiper trips until the hole stabilized and at the end of the day we started to retrieve the drill string. Our next step will be to install and cement 58.7 m of 16 inch casing. This will extend 6 m into basement.

Daily Science Report for 14 October 2011

LOCATION: Site U1383 (NP-2; 22.802°N, 46.053°W, water depth 4425 mbrf)

SCIENCE UPDATE: Today started with the re-entry cone and 34.7 m of 20 inch casing just above the seafloor. We were located ~25 m southwest of where we conducted the jet-in test with the 18.5 inch bit. Our jetting in of the reentry cone and casing proceeded well until 29 m. We spent three hours at this depth, but were unable to advance the casing any deeper into the formation. We pulled out of the seafloor and moved ~50 m to the northeast (~25 m NE of where our jet-in test was). At this location, we successfully installed the reentry cone and casing. We released the 20-inch casing running tool at 1035. Once the drill string and casing running tool was back on board, we assembled an 18.5-inch tri-cone bit and started lowering it to the seafloor. At the end of the day, the bit was about halfway to the seafloor. We'll use this18.5 inch bit to drill a hole ~15 m into basement into which we'll install 16 inch casing.

Daily Science Report for 13 October 2011

LOCATION: Site U1383 (NP-2; 22.802°N, 46.053°W, water depth 4425 mbrf)

SCIENCE UPDATE: We completed the jet-in test with an 18.5 inch bit to verify the length of 20 inch casing to be installed with the reentry cone. The bit reached 36 m with a low penetration rate during the last two meters. The rest of our day was spent assembling 34.7 m of 20 inch casing to the re-entry cone and lowering it to the seafloor.

Daily Science Report for 12 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)
and Site U1383 (NP-2; 22.802°N, 46.053°W, water depth 4425 mbrf)

SCIENCE UPDATE: We installed the ROV platform for the CORK at Hole U1382A and then released the CORK running tool. This completed the installation of a new CORK observatory to perform long-term coupled microbiological, biogeochemical, and hydrological experiments in the uppermost oceanic crust. After we recovered the CORK running tool and seafloor beacon, we assembled an 18.5 inch tricone bit and lowered it to the seafloor. At the same time, we used dynamic positioning to move ~6 nmi to Site U1383 (NP-2) and by the end of the day, we were starting a jet-in test with the 18.5 inch bit to verify length of 20 inch-casing to be installed with the reentry cone. Our main objective at this site is to install a new CORK observatory to perform long-term coupled microbiological, biogeochemical, and hydrological experiments at several deeper levels in the oceanic crust. To accomplish this we will install three casing strings extending ~120 m into basement, core ~350 m below that, collect downhole logs, conduct hydrologic (packer) experiments, and install the new CORK.

Daily Science Report for 11 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: Today we finished assembling the new CORK observatory, lowered it to the seafloor, and successfully installed it in Hole U1382A. At the end of the day, we had assembled the ROV platform and started lowering it to the seafloor.

Daily Science Report for 10 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: Our attempts to conduct hydrologic (packer) flow tests of the uppermost oceanic crust were not successful. Ship heave of up to 3 m prevented us from being able to keep the packer set in the base of the casing for sufficient time to conduct the planned experiments. After we deflated the packer, we lowered the logging bit to the bottom of the hole to verify hole conditions before assembling/installing the new CORK observatory to perform long-term coupled microbiological, biogeochemical, and hydrological experiments in the uppermost oceanic crust. We were able to run to the bottom without any problems and only 1.5 m of fill was encountered. After retrieving the logging/packer bottom-hole assembly, we spent the second half of the day assembling the new CORK.

Daily Science Report for 9 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: After reentering Hole U1382A with a logging bit and drill string packer, our first run down the hole with the new in situ tool for detecting microbial life in ocean floor boreholes - the Deep Exploration Biosphere Investigative tool (DEBI-t) - was successful. The tool was lowered only to 4 m above the bottom of the hole to prevent damaging it – no fill or tight spots were encountered to this depth. While logging upward, the tool string lost power about 20 m from the casing shoe and the tool string was retrieved. After the logging cable head was replaced, we deployed a modified FMS tool string. The tool reached the total depth of the hole (210 m) and we collected log data up to ~141 m. At that depth, the tool encountered an apparent tight spot and then we had a very difficult time getting the tool back inside the logging bit. At the end of the day, we had rigged down from logging and prepared for hydrologic (packer) experiments. Following these, we’ll install a CORK observatory to perform long-term coupled microbiological, biogeochemical, and hydrological experiments in the uppermost oceanic crust.

Daily Science Report for 8 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: After finishing RCB coring in Hole U1382A from 110 to 210 m, we performed a wiper trip to prepare the hole for downhole logging, hydrologic (packer) experiments, and the CORK installation. During the first trip up to casing and back down to bottom, we encountered several tight spots and found 3 m of fill on the bottom of the hole. During a second trip, no tight spots or fill were encountered but we were unable to rotate when back at the bottom of the hole. On the third trip, no fill was found on bottom, but a few tight spots were encountered. After two more wiper trips without any tight spots or fill, we pulled out of the hole and the bit was back on board at 1430. The next thing we did was to assemble and paint the perforated and coated drill collars for the lowermost part of the CORK to be deployed a few days from now. The rest of the day was spent assembling the logging and packer bottom hole assembly and lowering it to the seafloor.

Daily Science Report for 7 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: We took the final cores from Hole U1382A today. Cores 10R to 12R extend from 180.5 to 210.0 mbsf (29.5 m) and recovered 7.5 m (26% recovery). Basaltic rocks recovered are massive porphyritic flows and pillowed aphyric flows. Samples for microbiologic analyses continue to be taken immediately after the cores are opened in the lab. The cores are in various stages of processing with all cores through 8R completed with track system analyses and split. We are imaging the full outer surface of the whole round core pieces that are coherent and of sufficient length. Our next activity is to perform a wiper trip to prepare the hole for downhole logging, hydrologic (packer) experiments, and CORK installation.

Daily Science Report for 6 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: As of 0800 on 6 October, we've recovered RCB Cores U1382A-2R to 9R from 110.0 to 180.5 mbsf and recovered 24.3 m (34% recovery). Samples for microbiologic analyses are being taken immediately after the cores are opened in the lab. The cores are in various stages of processing, however we have recovered a wide range of rocks including massive aphyric basalt with alteration halos; massive aphyric pillow basalts with veins; breccia containing basalt, peridotite (some apparently mildly mylonitized), gabbros, and sediment; and porphyritic basalt. Current plan is to core 100 m (to 210 mbsf), and then log, conduct hydrologic (packer) test, and CORK Hole U1382A.

Daily Science Report for 5 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: We spent the majority of the day lowering the RCB bit to the seafloor. After we reentered Hole U1382A in less than two minutes (in a water depth of 4483 m), we lowered the bit into the hole and encountered cement in the casing within 1 m of the planned depth. We drilled the cement out and started cutting the first core at 2115 h from 110.0 to 113.3 mbsf. Just before midnight, Core U1382A-2R arrived on deck with 1.31 m of basalt (40% recovery). The current plan is to core 100 m (to 210 mbsf), and then log, conduct hydrologic (packer) test, and CORK Hole U1382A.

Daily Science Report for 4 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: After installing and cementing 102 m of 10.75 inch casing (~12 m into basement), we offset 50 m east to Hole 395A. We got as close as possible to the re-entry cone and ROV platform to obtain images for scientists to work with ROV pilots to plan what might be done to retrieve the instrument string in a few years. The rest of the day was spent retrieving the drill string. Our next step is to assemble an RCB bit, reenter Hole U1382A, drill out the cement at the bottom of the casing, and core ~100 m of basaltic crust. Anticipate core on deck around midnight tomorrow (5 Oct). Scientists continue to refine basalt and microbiology research and sampling plans in advance of core arriving.

Daily Science Report for 3 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: Today we drilled a 14.75 inch hole to 110 mbsf (~17 m into basement). Near the end of the day, we had recovered the drill bit and began preparing to run 102 m of 10.75 inch casing. Scientists continue to refine basalt research and sampling plans and attended a presentation on intra-terrestrial life.

Daily Science Report for 2 October 2011

LOCATION: Hole U1382A (22.756°N, 46.081°W, water depth 4494 mbrf; 50 m west of Hole 395A)

SCIENCE UPDATE: Today we installed the re-entry cone and 53 m of 16 inch casing in Hole U1382A. By the end of the day, we were lowering a 14.75 inch drill bit to the seafloor. We expect basaltic crust to be at ~93 mbsf and plan to drill a hole without coring 20 m into the crust. After that, we’ll install 10-3/4 inch casing about 10 m into basement, RCB core ~100 m of basalt, conduct downhole logging and hydrologic packer tests, and install a CORK observatory. Microbiologists met to finalize their basalt research and sampling plans. Scientists also met with lab specialists to discuss thin section capabilities and requirements.

Daily Science Report for 1 October 2011

LOCATION: Arrived at Site U1382, 50 m west of Hole 395A

SCIENCE UPDATE: We returned to the North Pond drilling area after tropical storm passed almost directly over the area. Our first operation here is to install the seafloor structure for the observatory. We assembled a re-entry cone and 53 m of 16 inch casing. Late in the day we started lowering it to the seafloor. Scientists met with operations superintendent and engineers to finalize the casing and logging plan for Hole U1382A. Scientists also met with lab specialists to get discuss ICP/XRD capabilities and requirements.