IODP Expedition 366
Mariana Convergent Margin and South Chamorro Seamount
Daily Science Report for 31 December 2016
Location: Hole U1492D (15°42.57′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: After slow penetration and very challenging conditions drilling the casing into the seafloor, progress was halted at 184 mbsf by poor hole conditions and the bit was pulled back up to 96 mbsf to free the casing. Over the afternoon and evening, the hole was reamed and drilled to the target depth of 214 mbsf, where the casing was finally landed in the reentry cone. It is not clear if the casing was fully latched, because visibility was obscured by mud in the reentry cone. The casing running tool was unlatched at 2240 h and by the end of the day the drill pipe was being raised back to the ship. The science party attended a presentation about iron in serpentinites during subduction. At 2400 h the science party, IODP JRSO technical staff, and ship’s crew gathered on the bow, and the youngest and oldest rang the ship’s bell to mark the New Year.
Daily Science Report for 30 December 2016
Location: Hole U1492D (15°42.57′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: Drilling the 211 m long casing string into Hole U1492D continued during the day, while battling against adverse hole conditions. The serpentinite mud in this environment appears to close up the hole more quickly than typical pelagic or siliciclastic sediments; moreover, rock clasts in the serpentinite mud fall to the bottom of the hole and take time to grind through and sweep out. Mud sweeps were employed to keep the hole open. By the end of the day drilling reached 145 mbsf. The science party attended a presentation about the ophiolite serpentinite mélange of the Coast Range, California.
Daily Science Report for 29 December 2016
Location: Hole U1492D (15°42.57′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: After completing our drilling of a 14.75 inch hole to 225 m yesterday, we finished recovering the drill string at 0315 h today. We then started preparing for our second attempt to install casing. The underreamer was tested and serviced, and the 211 m of casing was moved from its storage position back to the center of the moonpool. The bottom-hole assembly was made up and lowered through the casing, and the running tool latched into the casing. The drill string and casing were lowered to the seafloor and reentered Hole U1492D at 2300 h. By the end of the day the bit reached 38 mbsf. The science party attended a presentation about alkaline hyrdrothermal fluid vents from mafic and ultramafic rocks.
Daily Science Report for 28 December 2016
Location: Hole U1492D (15°42.57′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: Drilling progressed in Hole U1492D, reaching the target depth of 225 mbsf at 1015 h. The drill bit was raised to 67 mbsf then run back down to 225 mbsf, and the hole was swept three times with high-viscocity mud to clean out the hole prior to the casing operation. By the end of the day, the drill string was being pulled back up to the ship. The science party held a meeting to present and discuss the results obtained at Site U1492.
Daily Science Report for 27 December 2016
Location: Hole U1492D (15°42.57′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: After conditions in Hole U1492D prevented casing to be drilled in below 92.6 mbsf, we decided on a different approach. The hole is to be drilled without coring to 225 mbsf using a 14.75 inch bit, then reentered to drill in the casing using the mud motor and underreamer bit. The 211 m long casing was hung off the forward side in the moonpool and the drilling bottom-hole assembly was made up. Hole U1492D was reentered at 1415 h, and at the end of the day drilling reached 164.3 mbsf.
Daily Science Report for 26 December 2016
Location: Hole U1492D (15°42.57′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: At 0140 h while drilling casing into Hole U1492D with a mud motor and underreamer bit, a hard layer was encountered at ~83 mbsf, a similar depth to a hard layer encountered while coring in Hole U1492C. The layer was catching on to the bit, causing the drill pipe to torque up and then de-torque in the opposite direction when the bit was freed. On one such de-torque, the pipe rotated enough to release the reentry cone, and the reentry cone fell to the seafloor. At 0230 h, the 211 m long casing string disengaged from the running tool. We could still drill ahead and we were able to reengage the casing, reaching 92.6 mbsf. However, hole conditions remained poor and it was decided to pull the casing back to the ship and inspect the casing and drilling assemblies. On recovery, one cone was missing from the underreamer, but other parts of the assemblies were found to be in working order.
Daily Science Report for 25 December 2016
Location: Hole U1492D (15°42.57′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: After further testing of the underreamer bit, the bottom-hole assembly (BHA) with the drilling stinger (bit, underreamer, and mud motor) was made up, lowered through the reentry cone and casing, then latched into it. At 0630 h the driller began lowering the reentry cone/casing assembly to the seafloor. The camera system was deployed to observe the reentry cone while drilling the 210 m long casing string into the seafloor. Hole U1492D was started at 1620 h and by 2400 h the casing had been drilled in to 63.6 mbsf. Scientists continued report-writing, and celebrated Christmas with the IODP JRSO staff and ship’s crew.
Daily Science Report for 24 December 2016
Location: Hole U1492C (15°42.56′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: After pulling the drill string up to the ship following completion of Hole U1492C, the rig floor crew spent most of the day assembling equipment to drill casing into Hole U1492D. The 208 m total length of 10.75 inch casing includes four joints of screened casing placed near the base which, when deployed, will let formation pore fluids enter. The evening was spent making up and troubleshooting the running tool and casing hanger. Scientists continued geochemical analyses and writing reports.
Daily Science Report for 23 December 2016
Location: Hole U1492C (15°42.56′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: Coring of Hole U1492C continued, interspersed with wiper trips with high viscosity drilling mud to keep the hole open as drilling became progressively more difficult throughout the day. Cores U1492C-24F to 27F, 28G, and 29X to 31X penetrated to 139.1 mbsf and recovered 6.6 m (18%). Coring in Hole U1492C ended at 2100 h because of a further a loss of drill pipe rotation. The pipe was worked free and Core U1492C-31X was recovered. Cores 24F and below consist of bluish serpentinite mud with variably serpentinized ultramafic clasts. White brucite precipitates composed the lowermost ~30 cm of Core U1492C-31X.
Daily Science Report for 22 December 2016
Location: Hole U1492C (15°42.56′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: Half-length piston coring of Hole U1492C continued for most of the day. Cores U1492C-10X and 11F–23F penetrated to 98.7 mbsf and recovered 34.7 m (53%). At 2100 h, the T2P tool was prepared for deployment to measure downhole temperature and pressure. However, during hole conditioning prior to the T2P run, the drillers lost rotation of the drill string, but were able to free it. We decided that the hole would not be stable enough to stay open while the drill string remained non-rotational during the ~30 min required for the T2P measurements. The hole was swept with high viscosity mud to prepare for resumption of coring. Cores U1492C-10X and 11F–23F consisted of bluish serpentinite mud with variably serpentinized ultramafic clasts.
Daily Science Report for 21 December 2016
Location: Hole U1492C (15°42.56′N, 147°10.60′E, water depth 3666 mbsl; proposed Site MAF-15A)
Science Update: From 0000 to 1025 h, Cores U1492B-7F to 13F were recovered to 51.4 mbsf, completing the hole. Coring in Hole U1492B penetrated a total of 51.4 mbsf and recovered 52.0 m (101%). The ship was moved 100 m south to the location of the previously-identified seep and we started coring in Hole U1492C at 1230 h. Cores U1492C-1H and 2F–8F reached 32.9 mbsf, recovering 26.7 m (81%). Formation (APCT-3) temperature measurements were made while taking Cores U1492C-3F (9.5 mbsf) and 6F (23.5 mbsf). Cores U492B-3F to 13F consisted of serpentinite mud with variably serpentinized ultramafic clasts.
Daily Science Report for 20 December 2016
Location: Hole U1492B (15°42.62′N, 147°10.60′E, water depth 3669 mbsl; proposed Site MAF-15A)
Science Update: From 0000 to 0545 h the rig floor crew freed the core line that had been stuck in the oil saver, cut 115 ft to remove the damaged part, and reheaded the line to the sinker bars. Hole U1492A reached 38.3 mbsf with 38.5 m recovered (100%). The vessel offset 100 m to the south and Hole U1492B was spudded at 1045 h after two empty mudline cores that resulted from the ~12 m deeper seafloor at Hole U1492B compared to Hole U1492A. After the initial full-length APC core we switched directly to half-length APC, based on the coring characteristics of the material from the first hole at this site. Cores U1492B-2F to 6F then penetrated to 29.8 mbsf. The cores described today (U1492A-7F to 9F; U1492B-1H to 3F) consisted of serpentinite mud with variably serpentinized ultramafic clasts. The science party met to present and discuss the first results from Site U1491.
Daily Science Report for 19 December 2016
Location: Hole U1492A (15°42.68′N, 147°10.60′E, water depth 3657 mbsl; proposed Site MAF-15A)
Science Update: The seafloor video survey for Site U1492 began shortly after midnight and almost immediately observed our target, a seep, identified by a marker that scientists had left during a Jason II ROV dive in 2003. Therefore a full survey was not needed and the camera system was returned to the ship. Hole U1492A (proposed Site MAF-15A) was started at 0725 h, recovering 5.44 m of sediment and establishing a seafloor depth of 3657 mbsl. Coring started with the APC, but after some lengthwise compression of the Core U1492A-2H liner in the stiff sediment, we decided to switch to half-length APC (HLAPC) coring. Cores U1492A-3F to 8F penetrated from 19.3 to 33.6 mbsf with 90% recovery. Core U1492A-9F was cut, but on retrieval the core line became stuck in the oil saver above the top drive and at the end of the day the rig floor crew were working on freeing the line. Cores U1492A-1H to 6F consisted of serpentinite mud with variably serpentinized ultramafic clasts.
Daily Science Report for 18 December 2016
Location:
Site U1491 (15°47.12′N, 147°8.49′E, water depth 4511 mbsl; proposed Site MAF-16A)
Transit to Site U1492 (proposed Site MAF-15A)
Site U1492 (15°42.57′N, 147°10.60′E, water depth 3677 mbsl; proposed Site MAF-15A)
Science Update: Scientists continued to work on the remaining cores from Site U1491 and started to write up the Site U1491 chapter. At midday, the science party met for a presentation by our two Education and Outreach officers about the activities they have planned for the expedition. By the end of the day, the drill string had reached the seafloor in preparation for the video survey prior to starting Hole U1492A.
Daily Science Report for 17 December 2016
Location: Hole U1491C (15°47.19′N, 147°8.41′E, water depth 4492 m; proposed Site MAF-16A)
Science Update: We started coring in Hole U1491C at 0025 h. Cores 1H–2H, 3F–8F, and 9X penetrated to 34.2 mbsf and recovered 23.09 m (68%). Hole U1491C consists of similar sediments to those at Hole U1491B, but has a slightly different stratigraphy, which is unsurprising given that the two holes are 200 m apart and are located on an ~10% slope of a seamount. In Hole U1491C, the top unit of red-brown clay-rich pelagic mud is the same as in U1491, but underlying that there are intervals of breccia-conglomerate with a clay-silt matrix and carbonate clasts, matrix-supported conglomerate with carbonate and serpentinized ultramafic clasts, and grey-green serpentinite pebbly mud with ultramafic clasts. Downhole advance was slowed by gravel in the sequence, so we switched from full length APC to half-length APC, and then to XCB coring. Hole U1491C ended when a drill collar failed around the seafloor and left the lowermost ~30 m of the bottom-hole assembly in the hole.
Daily Science Report for 16 December 2016
Location: Site U1491 (15°47.12′N, 147°8.49′E, water depth 4511 mbsl; proposed Site MAF-16A)
Science Update: The day started with the rig floor crew continuing to trip pipe to the seafloor. The PDR (3.5 kHz precision depth recorder) seafloor depth value at this site is an underestimate because the seafloor slopes at ~10° on this side of Blue Moon Seamount, so for some tens of meters above the seafloor the pipe was advanced slowly, using the top drive, to tag the seafloor and estimate the water depth at Hole U1491A. The first core of the expedition, Core U1491A-1H, was recovered from this tag and is essentially a push core, composed of 1.32 m of brown clay. After recovering Core U1491A-1H, we spent the rest of the day coring in Hole U1491B. Cores U1491B-1H to 5H penetrated from 0–19.4 mbsf (18.98 m recovered; 98%); they were composed of a wide variety of materials including brown clay, carbonate gravel to pebble-sized pieces, serpentinite mud with rock clasts, and graded gravel beds. We attempted formation temperature measurements while taking Cores 2H (13.2 mbsf) and 5H (19.4 mbsf). Due to the continued presence of fine to coarse gravel, we stopped coring in Hole U1491B just before midnight, pulled the bit out of the hole, and started to offset the ship 200 m to the NW to start coring our next hole.
Daily Science Report for 15 December 2016
Location:
In transit
Site U1491 (15°47.12′N, 147°8.49′E, water depth 4511 m; proposed Site MAP-16A)
Science Update: Most of the day was spent in transit to Site U1491. The scientists met for a recap of CORK-removal operations at Site 1200C and to review the aims and setting of Site U1491. At the meeting we also discussed the plans for taking whole-round samples and gases on the catwalk, and selecting hard rock clasts for sampling during shift crossovers. IODP technicians made test measurements on the new cryogenic magnetometer and fixed the vane shear apparatus. The scientists continued to work on laboratory procedures and document these in their Methods chapters.
Daily Science Report for 14 December 2016
Location:
ODP Hole 1200C (13°47.07′N, 146°0.17′E, 2932 m water depth; Site MAF-4B)
In transit to Site U1491 (proposed Site MAP-16A)
Science Update: CORK fishing operations proceeded throughout the day. The fishing assembly latched onto the Hole 1200C CORK at 1015 h, but only part of the CORK came free. It was retrieved to the rig floor by 1700 h. The CORK parts were partially covered with precipitates and macrofauna, which were sampled by the scientists. The planned WSTP deployment could not be carried out because of the CORK parts that remained in the hole. At 2112 h, we started the ~137 nmi sea passage to Site U1491. The scientists spent most of the day working on laboratory procedures, documenting these in their Methods chapters, and continuing to transition onto their work shifts.
Daily Science Report for 13 December 2016
Location:
Dock F3, Port of Guam
In transit to ODP Hole 1200C (Site MAF-4B)
Science Update: We departed Guam at 0518 h, beginning our ~11 h transit to ODP Site 1200 on South Chamorro Seamount. The Operations Superintendent gave a presentation on coring operations and tools, then the scientists split into four groups to receive presentations on core sampling and core flow. Throughout the day, the laboratory groups met with their laboratory technicians to discuss sampling, analytical procedures, and core description. The scientists started to transition to their shifts. At 1624 h, the ship arrived on site, then the rig floor crew made up the fishing assembly and bottom-hole assembly for the attempt to retrieve the CORK from Hole 1200C.
Daily Science Report for 12 December 2016
Location: Dock F3, Port of Guam
Science Update: The science party divided into laboratory groups, and the core description scientists, physical properties specialists, geochemists, and microbiologists each met with the IODP JRSO technicians in their respective laboratories for an introduction to laboratory equipment and methods. Scientists continued to set up their third party instruments and prepare for sampling and analysis. In the afternoon, the science party was free to leave the ship, in anticipation of departure from Guam the following morning.
Daily Science Report for 11 December 2016
Location: Dock F3, Port of Guam
Science Update: The Expedition 366 science party met to discuss the Methods chapter for the Proceedings volume. The Geochemistry and Microbiology teams continued discussions on sampling, sample preparation, analysis, and storage. The Core Description team began discussion of how to describe the serpentinite mud volcano materials within the DESClogik core description software. Science party members started to set up their third party scientific instruments. Installation of the new cryogenic magnetometer was close to complete. In the afternoon, the science party was free to leave the ship.
Daily Science Report for 10 December 2016
Location: Dock F3, Port of Guam
Science Update: The Co-Chief Scientists introduced the scientific objectives of the Mariana Convergent Margin expedition, and each scientist presented a short summary of their scientific background and their proposed postcruise research. In the afternoon, the Captain welcomed the scientists to the vessel and gave an introduction to policies and procedures aboard the JOIDES Resolution, and the Ship’s Doctor conducted a shipboard safety meeting. The laboratory groups met to discuss sampling for shipboard analysis and postcruise research. Access to the core deck laboratories remained restricted because of the ongoing installation of the new cryogenic magnetometer.
Daily Science Report for 9 December 2016
Location: Dock F3, Port of Guam
Science Update: The Expedition 366 science party boarded the vessel at 0940 h and the scientists were shown to their berths. A short introductory meeting was held and the scientists had their photos taken. At 1300 h, the science party convened for presentations about life aboard the vessel and general safety. The science party then divided into three groups for a ship safety tour. The Marine Computer Specialists gave the scientists an introduction to I.T. and computing aboard the JOIDES Resolution and helped the scientists connect their computers to the ship’s network. The final science party member boarded the vessel at ~2000 h and was given a brief tour of the ship.
Daily Science Report for 8 December 2016
Location: Dock F3, Port of Guam
Science Update: The Mariana Convergent Margin Expedition (366) began with the first line ashore at 0648 h. Oncoming IODP JRSO technical staff and the Co-Chief Scientists boarded the vessel at 0930 h and completed crossover with the offgoing staff, who departed the vessel early in the afternoon. The Co-Chief Scientists settled in and received a tour of the ship from the Staff Scientist. They then spent the afternoon getting set up in the Science Office, going over the schedule for port call, and preparing for the arrival of the science party.