IODP Expedition 376
Brothers Arc Flux
Daily Science Report for 31 May 2018
Location: Hole U1528D (34°52.9219′S, 179°4.1164′E, water depth 1228 mbsl; proposed Site UC-1A)
Science Update: We continued drilling down in Hole U1528D from 39 to 50 m with the possibility that the casing would continue to slide into the hole following the bit. However, after observing that the casing was not following the bit, we attempted to move the casing with the underreamer arms to no avail for 2 h. We then continued drilling the 16½ inch hole from 50 m to the planned total depth of 61 m, which was reached at 0640 h. We reamed the hole and pulled the drill string out of the hole with the bit clearing the reentry cone at 0954 h. We were able to observe that the reentry cone remained standing independently despite being ~23 m above the seafloor. We also observed that Hole U1528D was drilled in the flat central area of the pit crater. We set back the top drive, recovered the subsea camera, and pulled the drill string out of the hole with the bit clearing the rig floor at 1605 h. Subsequent function tests of both the mud motor and underreamer were successful. Our next objective was to reenter Hole U1528D to get the reentry cone and casing to settle to the appropriate depth. For this purpose, we installed a 13⅜ inch cup seal on top of the drilling assembly to seal the inside of the casing while circulating. This is intended to clean the annulus between casing and surrounding formation to promote complete settling of the casing string into the hole. We deployed the subsea camera and sonar system at 2245 h and continued lowering the drill string to the seafloor for the rest of the day.
Scientists continued to collect, analyze, and write up Hole U1529A and Hole U1529B data. We held our second meeting for the laboratory groups to present a summary of their Hole U1528A/U1528C results.
Daily Science Report for 30 May 2018
Location: Hole U1528D (34°52.9219′S, 179°4.1164′E, water depth 1228 mbsl; proposed Site UC-1A)
Science Update: We continued preparing the reentry cone and ~59 m long casing string for drilling in Hole U1528D. We made up the 13⅜ inch casing connection in the moonpool, installed the reentry cone, and welded it onto the casing hanger. After we installed the hard rock frame and welded it to the casing by 0500 h, we waited for weather to improve to lower the reentry cone and casing to the seafloor. At 1200 h, we started lowering the reentry system to the seafloor. The subsea camera and sonar system was deployed at 1545 h and it was lowered to the seafloor along with the drill string. We picked up the top drive and started drilling the casing into Hole U1528D at 1750 h. We encountered firm formation between 13 and 15 m. At 2100 h, the casing running tool (hydraulic release tool) prematurely released at a depth of 33.5 m. We decided to continue drilling down with the possibility that the casing will continue to settle into the hole following the bit. The bit reached 39 m by the end of the day, and we pumped mud sweeps at 25.9 and 35.5 m.
Scientists continued to collect, analyze, and write up Hole U1529A and Hole U1529B data. Also, we held our first meeting for the laboratory groups to present a summary of their Hole U1528A/U1528C results.
Daily Science Report for 29 May 2018
Location: Hole U1528D (34°52.93′S, 179°4.10′E, water depth 1229 mbsl; proposed Site UC-1A)
Science Update: We continued recovering the drill string and the bit reached the rig floor at 0025 h, ending Hole U1528B. The rest of the day was spent preparing a reentry cone and casing that will be drilled into the seafloor at Hole U1528D. This consisted of (1) assembling a mud motor, underreamer, and 12¼ inch tri-cone drilling bit to form the drilling assembly; (2) connecting five joints of 13⅜ inch casing to form a ~59 m long casing string; (3) installing and testing the drilling assembly; and (4) landing the casing running tool (hydraulic release tool) in the moonpool and attaching it to the casing string. Scientists continued to collect, analyze, and write up Hole U1528C, Hole U1529A, and Hole U1529B data.
Daily Science Report for 28 May 2018
Location:
Hole U1529B (34°52.5217′S, 179°3.5207′E, water depth 1733 mbsl; proposed Site WC-1A)
Hole U1528B (34°52.93′S, 179°4.10′E, water depth 1229 mbsl; proposed Site UC-1A)
Science Update: Cores U1529B-2R to 3R penetrated from 15 m to a final total depth of 34.4 m and recovered 0.3 m (2%). We observed a tight hole at the total depth and attempted to work it back to ~15 m. We dropped a core barrel to improve circulation, but circulation was lost when the bit was at 15 m. We decided to abandon Hole U1529B, as the drill bit and jets were plugged with debris and the hole conditions were extremely unstable. We pulled the drill string out of the hole and the bit cleared the seafloor at 1015 h, ending Hole U1529B. We recovered the core barrel that was in place while attempting to get back to the bottom of the hole (ghost Core 4G; 8.17 m recovered). Then, we set back the top drive and continued raising the bit to a depth so that we could return to shallower water Site U1528 in the Upper Cone of Brothers volcano using the dynamic positioning system. We arrived at the location of cased Hole U1528B at 1530 h, deployed the subsea camera, and picked up the top drive. We started our attempts to reenter Hole U1528B at 1730 h, but immediately experienced excessive drill string torque and little downward progress. We were unable to operate below the reentry cone because the seafloor structure is tilted. We abandoned attempts to reenter Hole U1528B at 1915 h and started recovering the drill string.
Cores U1529B-1R to 3R have been split and described today. They consist of fresh to slightly altered plagioclase(-clinopyroxene) phyric, glomeroporphyritic dacite with high vesicularity and hypohyaline groundmass. The elongate vesicles are subrounded to angular. Minor alteration is dominated by iron oxide coating and vesicle infilling. The dacite lava occurs as pebbles embedded in an unconsolidated ash-lapilli matrix that has been extensively recovered by ghost Core 4G. The scientists attended a talk by the microbiologists on their archaea research and continued to collect, analyze, and write up Hole U1528C data.
Daily Science Report for 27 May 2018
Location:
• Hole U1528C (34°52.9215′S, 179°4.1128′E, water depth 1229 mbsl; proposed Site UC-1A)
• Hole U1529A (34°52.5161′S, 179°3.5139′E, water depth 1733 mbsl; proposed Site WC-1A)
• Hole U1529B (34°52.5217′S, 179°3.5207′E, water depth 1733 mbsl; proposed Site WC-1A)
Science Update: We continued pulling the drill string out of Hole U1528C, recovered the broken turbine-driven coring system core barrel section, and the bit returned to the rig floor at 0430 h, ending Hole U1528C. We then started making up the rotary core barrel (RCB) bottom-hole assembly and lowering the drill string to the seafloor. We deployed the subsea camera system while moving to Site U1529 on the western caldera floor. We surveyed the seafloor at Site U1529 and tagged possible hole positions. After picking up the top drive, we retrieved the subsea camera system and started RCB coring in Hole U1529A at 1610 h. After Core U1529A-1R penetrated to a depth of 12 m and recovered 1.9 m (16%), we observed high torque and had to work a tight hole from 12 m to the seafloor. We then pulled the drill string out of the hole because of bad hole conditions related to unconsolidated volcanic deposits. The bit cleared the seafloor at 1925 h, ending Hole U1529A. We retrieved Core 1R, dropped the core barrel, and started RCB coring in Hole U1529B at 2030 h. Core U1529B-1R penetrated to 15 m by midnight.
Core U1529A-1R has been split and described today. It consists of unaltered plagioclase phyric, highly vesicular, hypohyaline dark gray dacite pebbles and black to dark gray ash to lapilli, forming a deposit of loose tephra.
Daily Science Report for 26 May 2018
Location: Hole U1528C (34°52.9215′S, 179°4.1128′E, water depth 1229 mbsl; proposed Site UC-1A)
Science Update: After we were prevented from reentering Hole U1528B with the turbine-driven coring system (TDCS) by the angle of the reentry funnel, we offset the vessel and tagged the seafloor to establish a depth for Hole U1528C. The subsea camera system was recovered and we started drilling Hole U1528C at 0230 h and drilled down from the seafloor to 22 m, reached at 0630 h. We then installed the TDCS core barrel and began TDCS coring in the seafloor for the first time ever. Cores U1528C-2N to 8N penetrated from 22.0 m to a final total depth of 53.5 m at full 4.5 m advancements and recovered 3.6 m (11.5%). We pumped 30 barrels of mud sweeps at 31, 35.5, 40, 44.5, and 49 m. When Core 8N was pulled, we observed that only the top third of the core barrel was recovered. The core barrel had actually parted in the reduction gear, so that the lower core barrel remained in the bottom-hole assembly. We started pulling the drill string out of the hole, cleared the seafloor at 2330 h, and set back the top drive.
Cores 2N to 8N have been split and described today. They consist of poorly to well sorted, unconsolidated or cemented volcaniclastic rock, partially identified as lapilli tephra. The light gray to bluish gray rocks are intensely altered and made up of pebble-sized clasts of volcanic origin. Clay, disseminated pyrite, sulfates, native sulfur, and magnetite comprise the dominant alteration minerals. Haloed vuggy veinlets made up of clay, sulfate, and native sulfur rarely occur in Core 5N. Overall, the recovered material is similar to the rocks brought up from Hole U1528A. From 1130–1230 h, we held a meeting for the Expedition 376 laboratory groups to present a summary of their Site U1527 results.
Daily Science Report for 25 May 2018
Location:
Hole U1528B (34°52.93′S, 179°4.10′E, water depth 1229 mbsl; proposed Site UC-1A)
Hole U1528C (34°52.93′S, 179°4.10′E, water depth 1229 mbsl; proposed Site UC-1A)
Science Update: After observing the barely visible reentry funnel at the seafloor, we recovered the subsea camera system and pulled out of Hole U1528B. Once the drilling assembly had reached the moonpool, we flushed the mud motor and underreamer with fresh water. The bit returned to the rig floor at 0450 h, ending Hole U1528B. We reassembled the rig floor and carried out a routine cut and slip of 115 ft of the drilling line. At 1045 h, we started assembling the CDEX turbine-driven coring system (TDCS). Upon completing the assembly, we successfully tested the function of the TDCS core barrel on the rig floor. At 1800 h, we started lowering the TDCS bottom-hole assembly, including a polycrystalline diamond compact (PDC) bit. We then deployed the subsea camera system to assist in an attempt to reenter Hole 1528B and continued lowering the drill string. We picked up the top drive and attempted to reenter Hole U1528B at 2245 h. After making several attempts, we paused for reevaluation, as the PDC bit hung up in the reentry funnel throat, possibly due to the base of the reentry system not sitting flat on the seafloor. Scientists continued to collect, analyze, and write up Hole U1528A data, and they submitted the drafts of their Site U1527 reports to the Science Office and finalized their presentations for the Site U1527 science summary meeting.
Daily Science Report for 24 May 2018
Location: Hole U1528B (34°52.93′S, 179°4.10′E, water depth 1229 mbsl; proposed Site UC-1A)
Science Update: The day began with waiting on weather to improve enough to deploy the reentry system for Hole U1528B. At 1100 h, we finally picked up the reentry system and started it lowering through the open moonpool doors to the seafloor. We then deployed the subsea camera and sonar system at 1515 h and continued lowering the drill string to the seafloor. The position of Hole U1528B was located by sonar and it was reentered at 1645 h. We then drilled from 13.0 to 25.6 m. After dropping the go-devil to release the reentry system, we observed the hydraulic release tool (HRT) inside the throat of the reentry cone, but initially we could not pull the drill string out further. The underreamer arms apparently were not completely pulled inside the casing shoe. After working the drill string with varying pump strokes, we were able to retract the drilling stinger (mud motor, underreamer, and drill bit) from the reentry system. We retrieved the subsea camera system and pulled the drill string out of the reentry system with the drilling stinger sliding through the casing with drag, clearing the top of the reentry cone at 2330 h. We then lowered the subsea camera system back to the seafloor with a changed running sleeve for being able to pass the HRT to verify the landing position of the reentry cone. The cone appeared to be on the seafloor. Scientists continued to collect, analyze, and write up Hole U1528A data, as well as to prepare their Site U1527 reports and presentations for the Site U1527 science summary meeting.
Daily Science Report for 23 May 2018
Location: Hole U1528B (34°52.93′S, 179°4.10′E, water depth 1229 mbsl; proposed Site UC-1A)
Science Update: We continued pulling the drill string out of Hole U1528B, and the bit reached the rig floor at 0150 h. We then started casing operations. Our first step for Hole U1528B is to drill 10¾ inch casing into the seafloor to stabilize the uppermost formation. After assembling the 24 m long casing string, we lowered it to the moonpool and latched it to the mud skirt at 0930 h. We then prepared the drilling assembly (mud motor, underreamer, 9⅞ inch tri-cone bit) to drill in the reentry system. After we successfully tested the mud motor and underreamer in the moonpool, we lowered the drilling assembly through the casing and attached it with the hydraulic release tool to the casing flange on the mud skirt. Then, we assembled the reentry funnel and welded it to the casing hanger by 1500 h. The rest of the day was spent waiting for the weather to improve enough so that we could safely deploy the reentry system, given high surge in the moonpool as well as the need to precisely position Hole U1528B in the extremely limited areas of flat seafloor in the center of a steep-walled pit crater. Scientists continued to collect, analyze, and write up Hole U1528A data, as well as to prepare their Site U1527 reports and presentations for the Site U1527 science summary meeting.
Daily Science Report for 22 May 2018
Location:
• Hole U1528A (34°52.9177′S, 179°4.1070′E, water depth 1228 mbsl; proposed Site UC-1A)
• Hole U1528B (34°52.93′S, 179°4.10′E, water depth 1229 mbsl; proposed Site UC-1A)
Science Update: Half-length Cores U1528A-9R to 15R penetrated from 54.6 m to a final total depth of 84.4 m and recovered 7.5 m (25%). We pumped several mud sweeps at various depths to keep the hole clean. After cutting Core 15R at 1430 h, the drill string got stuck. We finally freed the drill string at 1730 h. While we were pulling it out of the hole, we had to work through poor hole conditions with high torque from 83 to 66 m, likely due to unconsolidated volcanic debris from the uppermost ~13 m of the hole. After the drill string cleared the seafloor, we offset the vessel 10 m to the south to the surveyed location of Hole U1528B. We then were able to retrieve Core 15R, ending Hole U1528A at 1945 h. Our primary objective for Hole U1528B is to determine the length of casing we will use to stabilize the uppermost unconsolidated formation so we can core deeply. At 2040 h, we started RCB drilling without coring using a center bit in Hole U1528B. After reaching a total depth of 13 m, we started pulling the drill string out of the hole, and the bit cleared the seafloor at 2100 h. We continued to recover the drill string for the rest of the day.
Cores 6R to 15R have been split and described today. They consist of cemented, mono- to polymict pyroclastic rock, being either matrix-supported lapilli-tuff or clast-supported lapillistone with pebble-sized volcanic clasts. These lithologies are highly to completely altered, reflecting an increasing degree of overprint with depth. The pervasive, gray to light bluish gray colored alteration is dominated by clay, barite, pyrite, native sulfur, and alunite. Interstitial veinlets and infillings of vugs are made up of barite with subordinate native sulfur and sulfide. The latter shows an increasing abundance downhole.
Daily Science Report for 21 May 2018
Location: Hole U1528A (34°52.9177′S, 179°4.1070′E, water depth 1228 mbsl; proposed Site UC-1A)
Science Update: We started the day with running the RCB bottom-hole assembly to the seafloor in preparation for coring. At 0400 h, we began a camera survey of the seafloor to identify four possible hole locations for Site U1528, tagging the seafloor at each location. After retrieving the subsea camera system and reassembling the rig floor, we picked up the top drive, dropped a core barrel, and started coring Hole U1528A at 0825 h. Cores 1R to 8R penetrated to 54.6 m and recovered 9.6 m (18%). We switched to half-length advances (4.8 m) on Core 7R. A substantial change to hard formation was noticed at 12.7 m. We pumped 30 barrels of mud sweeps at 35, 45, 49, and 54 m.
Cores 1R to 5R have been split and described today. Core 1R recovered unconsolidated polymict sand-sized lapilli tephra that contains blocks of subangular to subrounded, variably altered volcanic clasts of black to light gray color with disseminated native sulfur in vesicles. Sulfur is also present as lapilli. After two cores with no recovery, Cores 4R and 5R recovered poorly sorted, cemented lapilli tephra with blocks/bombs and matrix-supported lapilli-tuff, respectively, showing a matrix of highly altered volcanic ash and clay. Subrounded fine-grained clasts are made up of either highly altered vesicular volcanics or intensely silicified rocks. Bluish gray clay, silica, native sulfur, and pyrite are the predominant alteration minerals. Vugs are filled with fibrous or massive barite.
Daily Science Report for 20 May 2018
Location:
• Hole U1527C (34°51.6625′S, 179°3.2534′E, water depth 1464 mbsl; proposed Site NWC-1A)
• In transit to Site U1528 (proposed Site UC-1A)
• Hole U1528A (34°52.93′S, 179°4.10′E, water depth 1228 mbsl; proposed Site UC-1A)
Science Update: We continued to work the stuck drill string from 116 m to the seafloor, which was cleared at 0155 h. Unfortunately, the reentry system and casing again returned to the ship with the drill string. We secured the reentry system in the moonpool and removed the hard rock landing frame. Upon removal of the reentry funnel, we continued to work on releasing the drill string from the 94 m long 10¾ inch casing assembly. We broke the flange connection and cleaned out cuttings made of lapilli-sized tephra that clogged up the hydraulic release tool and upper casing sub. We worked the drill string up and down and eventually freed it from the casing. The bit was finally back on the rig floor at 1725 h, ending Hole U1527C. We laid out the casing—all eight joints were bent during the effort to pull out of hole. We moved the ship ~1.1 nmi to Site U1528 (proposed Site UC-1A) in dynamic positioning mode and began preparations for RCB coring in Hole U1528A. Scientists continued to collect, analyze, and write up Hole U1527C data.
Daily Science Report for 19 May 2018
Location: Hole U1527C (34°51.6625′S, 179°3.2534′E, water depth 1464 mbsl; proposed Site NWC-1A)
Science Update: Half-length Cores 16R to 20R penetrated from 214.0 to 238.0 m and recovered 8.5 m (35%). We pumped mud sweeps for hole cleaning at various depths. After cutting Core 20R at 0700 h, we observed a tight hole and had to work it from 234 to 125 m with high drill string torque and poor hole conditions, leading to stuck pipe at 125 m (30 m below the end of the casing string). We pumped mud sweeps at 234, 145, and 130 m. At 2045 h, we offset the vessel ~75 m to access a drill pipe connection at the rig floor to retrieve Core 20R and release the bit in an attempt to free the drill string. We offset the vessel to the original position at 2230 h and continued to work the stuck drill string from 125 to 116 m with high torque.
Cores 14R to 20R have been split and described today. They consist of pervasively altered, poorly sorted mono- to polymict lapilli-tuff to tuff-breccia, being either matrix- or clast-supported. Maximum cobble-sized, subrounded to subangular volcanic clasts show clay and chlorite alteration. Vugs are filled with zeolite, silica, and sulfide. The latter also occurs disseminated. Braided massive magnetite-pyrite and silica veins are rarely present. Cores 14R to 20R continue the highly to completely hydrothermally altered pyroclastic deposit recovered in Cores 11R to 13R.
Daily Science Report for 18 May 2018
Location: Hole U1527C (34°51.6625′S, 179°3.2534′E, water depth 1464 mbsl; proposed Site NWC-1A)
Science Update: Cores 2R to 15R penetrated from 99.9 to 214.0 m. The first nine of these cores partially took only 10 min to cut and had no to extremely poor recovery (0 to 0.54 m), retrieving pebbles of fresh to slightly altered, sparsely to highly plagioclase-pyroxene phyric, dark gray dacite lava with moderate to high vesicularity. While cutting Core 11R, we encountered a substantial formation change at ~187 m and core recovery increased to 29%. The time to cut Core 11R increased to 70 min. To enhance the core recovery even more, we decided to cut half-length cores (4.8 m), and recovery for the remainder of today’s cores improved to 72%. We circulated 410 barrels of mud sweeps for hole cleaning at various depths. The change in formation is reflected in the lithology—consolidated matrix-supported volcaniclastic breccia. Cores 11R to 13R have been split and described, revealing at least three different types of lapilli- to block/bomb-sized volcanic clasts (altered plagioclase phyric dacite, altered medium-grained clasts, fresh fine-grained clasts). The breccia is pervasively altered, displaying a yellowish brown to greenish blue color with secondary clay, iron oxide, zeolite, and subordinate pyrite.
Daily Science Report for 17 May 2018
Location: Hole U1527C (34°51.6625′S, 179°3.2534′E, water depth 1464 mbsl; proposed Site NWC-1A)
Science Update: Today we successfully drilled the 94 m long casing string into the seafloor when the pilot bit had reached 99.9 m. Immediately after this was completed, we deployed the go-devil to activate the hydraulic release tool, which freed the casing at 0045 h. We then started pulling the drill string out of the hole, reaching the seafloor at 0315 h. We set back the top drive, retrieved the subsea camera system, and the bit returned to the rig floor at 1150 h. After taking apart the drilling assembly, we flushed the mud motor and underreamer with fresh water. We then started making up the rotary core barrel (RCB) bottom-hole assembly at 1300 h and lowered it to the seafloor. We deployed the subsea camera system and reentered Hole U1527C at 2014 h. We picked up the top drive, dropped a core barrel, and recovered the subsea camera system. At midnight, the end of the casing string was reached and we began RCB coring from 99.9 m. Scientists continued to analyze and prepare reports on their Hole U1527A results. A scientist gave a talk on the alteration mineralogy of magmatic-hydrothermal systems studied at the surface of Brothers volcano to date.
Daily Science Report for 16 May 2018
Location: Hole U1527C (34°51.6625′S, 179°3.2534′E; water depth 1464 mbsl, proposed Site NWC-1A)
Science Update: We continued to recondition the drilling assembly and reentry system for our second attempt to drill it into the seafloor. We picked up the 94 m long casing string, reassembled the reentry funnel in the moonpool, welded the funnel and hard rock landing frame to the casing, inserted the drilling assembly, and lowered it to the seafloor. We deployed the subsea camera system at 0945 h to observe the reentry system while drilling in the casing, and we started drilling Hole U1527C at 1130 h. At midnight, the bit had reached 96.7 m with only a few more meters to achieve total depth. Scientists continued to collect, analyze, and write up Hole U1527A data. They also performed Kuster Flow-Through Fluid Sampler contamination tests in preparation for planned borehole fluid sampling.
Daily Science Report for 15 May 2018
Location:
• Hole U1527B (34°51.6519′S, 179°3.2526′E, water depth 1464 mbsl; proposed Site NWC-1A)
• Hole U1527C (34°51.65′S, 179°3.25′E, water depth 1464 mbsl; proposed Site NWC-1A)
Science Update: We continued drilling the 94 m long casing string into the seafloor until the pilot bit reached the final planned depth of 105.5 m at 0030 h. We activated the hydraulic release tool (HRT) to detach the drilling assembly from the casing at 0114 h, and we began recovering the drill string and the subsea camera system. When we attempted to pull the HRT through the moonpool, we observed that the reentry system was still attached to the drill string. We landed and dismantled the reentry system in the moonpool, and we were able to free the drilling assembly underreamer arms from the casing. When the drilling assembly was pulled up to the rig floor at 1530 h, we discovered that the pilot bit was missing. We started to recondition the drilling assembly and reentry system so that we can install it in Hole U1527C, 20 m south of Hole U1527B. Scientists continued to collect, analyze, and write up Hole U1527A data.
Daily Science Report for 14 May 2018
Location: Hole U1527B (34°51.6519′S, 179°3.2526′E, water depth 1464 mbsl; proposed Site NWC-1A)
Science Update: We continued to drill in casing from 34.3 to 102.1 m. We had to work several tight spots from 82 to 102 m. Scientists continued to collect, analyze, and write up Hole U1527A data. Portable X-ray fluorescence measurements confirmed the dacitic composition of the volcanics recovered in Hole U1527A.
Daily Science Report for 13 May 2018
Location: Hole U1527B (34°51.64′S, 179°3.22′E, water depth 1464 mbsl; proposed Site NWC-1A)
Science Update: We spent the entire day continuing casing operations, consisting of (1) assembling a mud motor, underreamer, and 9⅞ inch tri-cone bit; (2) connecting the hydraulic release tool to the 10¾ inch casing assembly; and (3) attaching the reentry funnel and hard rock landing frame to the casing. At 1000 h, we started lowering the entire 94 m long casing string and drilling assembly to the seafloor. We deployed the subsea camera system at 1530 h to observe the reentry system while drilling in the casing. We began drilling the casing into the seafloor in Hole U1527B at 1715 h. At midnight, the end of the casing had reached 34.3 m. Scientists continued to collect, analyze, and write up Hole U1527A data.
Daily Science Report for 12 May 2018
Location:
• Hole U1527A (34°51.6528′S, 179°3.2397′E, water depth 1464 mbsl; proposed Site NWC-1A)
• Hole U1527B (34°51.64′S, 179°3.22′E, water depth 1464 mbsl; proposed Site NWC-1A)
Science Update: We continued RCB coring from 87.0 to 101.4 m with extremely poor recovery. We pulled the drill string out of the hole at 0635 h, set back the top drive, and the bit was back on the rig floor at 1120 h, ending Hole U1527A. Overall, only 1.27 m of core was recovered from the 101.4 m cored in Hole U1527A. We offset the ship 20 m to the east and started preparing the rig floor for assembling a reentry cone and 94 m of casing that we will drill into the seafloor. Scientists continued to collect, analyze, and write up their final Hole U1527A data. The volcanic rock recovered at Hole U1527A probably represents dacite. The Co-Chief Scientists gave a short overview of the seafloor rock types and mineralization studies in caldera wall proximal to Hole U1527B.
Daily Science Report for 11 May 2018
Location: Hole U1527A (34°51.6528′S, 179°3.2397′E, water depth 1464 mbsl; proposed Site NWC-1A)
Science Update: We continued RCB coring throughout the day. Cores 2R to 12R penetrated from 9.7 to 87.0 m and recovered 1.27 m. The drill string occasionally became stuck, which required frequent pumping of mud sweeps. Core recovery (1.6%) was extremely poor in the unconsolidated volcanic deposits. The material recovered is mainly fresh to slightly altered, sparsely plagioclase phyric volcanic rock of gray to dark gray color, showing moderate to high vesicularity. Subordinate, polymict pumiceous lapilli tephra was also recovered.
Daily Science Report for 10 May 2018
Location:
• In transit
• Hole U1527A (34°51.65′S, 179°3.21′E, water depth 1464 m; proposed Site NWC-1A)
Science Update: After a 246 nmi transit from Auckland, we arrived at Site U1527 at 0800 h. Following lowering thrusters, we put together the rotary core barrel (RCB) bottom-hole assembly, and started running it to the seafloor in preparation for coring. We attached an APCT-3 temperature shoe to the subsea camera system and conducted a survey of the seafloor; we located the precruise site survey seafloor marker at 1745 h. After completing the survey of six potential hole locations, we retrieved the camera system, picked up the top drive, and reassembled the rig floor. We began coring in Hole U1527A from a water depth of 1464 m at 2240 h, pumping tracer material and measuring downhole temperatures through readings of temperature strips contained in a housing tool attached to the RCB core barrel head. By midnight, Core U1527A-1R was retrieved with no recovery. After a Site U1527 kickoff meeting, the science party broke out into laboratory groups to continue preparing their laboratories and methods. An inspection of the third-party Petrospec spool-in thermocouple assembly was conducted, including a ship-to-shore videoconference meeting to familiarize the petrophysics group and IODP JRSO technical staff with the equipment. The science party started their shifts at 1200 h.
Daily Science Report for 9 May 2018
Location:
• Wynyard Wharf, Port of Auckland, New Zealand
• In transit to Site U1527 (proposed Site NWC-1A)
Science Update: The science party was given a tour to the helideck by the Schlumberger logging engineers, where they received an introduction to the downhole logging tools and their preparation for high-temperature downhole measurements at Brothers volcano. The Education and Outreach Officers provided the scientists an overview of their plans for the expedition. In the afternoon, the captain held the first fire and boat safety drill. The Expedition Project Manager (EPM) gave a talk on downhole measurements. The IODP JRSO Operations Superintendent and CDEX technical engineers introduced drilling and coring operations. The Publications Specialist introduced the science party to IODP publications, as well as their obligations during the expedition and afterwards. The second half of the science party was given a core flow tour by the EPM. The laboratory groups continued learning their laboratories and preparing instruments and methods. Upon completion of fueling in the early morning, the pilot boarded the ship at 0758 h. The vessel departed Wynyard Wharf with the last line away at 0821 h, beginning our sea passage. The rest of the day was spent in transit to Site U1527 (proposed Site NWC-1A).
Daily Science Report for 8 May 2018
Location: Freyberg Wharf B/Wynyard Wharf, Port of Auckland, New Zealand
Science Update: The Expedition 376 Curator gave a talk on curation, followed by an introduction to core sampling on the core deck. Half of the science party was given a core flow tour by the Expedition Project Manager (EPM). All laboratory groups convened for meetings with the IODP JRSO technical staff to learn their laboratories and start preparing associated instruments. The loading of supplies and hardware was completed, including the CDEX turbine-driven coring system. A news team of the New Zealand nationwide TV channel “Three” visited the vessel and was given a tour and interview by the Co-Chief Scientists and EPM. The ship shifted to Wynyard Wharf for fueling with the first line ashore at 1930 h.
Daily Science Report for 7 May 2018
Location: Freyberg Wharf B, Port of Auckland, New Zealand
Science Update: Today began with introductions of the Expedition 376 scientists and IODP JRSO technical staff, a talk on the expedition science objectives by the Co-Chief Scientists, and a presentation of the expedition work plan by the Expedition Project Manager. In the afternoon, after the Captain’s introduction and safety orientation, scientists presented their individual research goals. The day was concluded with an introduction to the descriptive information system, given by IODP JRSO staff to the core describers. Initial laboratory team meetings took place. The loading of supplies and essential hardware (e.g., reentry systems) continued all day. We are tentatively scheduled to depart at 0800 h on May 9.
Daily Science Report for 6 May 2018
Location: Freyberg Wharf B, Port of Auckland, New Zealand
Science Update: The Expedition 376 scientists boarded the vessel at 0900 h, got settled in their rooms, and were given a short introductory talk and presentation on information technology aboard the JOIDES Resolution. They started to connect their computers to the shipboard network and had their photos taken. At 1300 h, the science party convened for presentations about life at sea and general safety that were concluded by a ship safety tour. Seven PR tours of the vessel took place as scheduled. Loading and discharge of freight continued throughout the day.
Daily Science Report for 5 May 2018
Location: Freyberg Wharf B, Port of Auckland, New Zealand
Science Update: The Brothers Arc Flux Expedition 376 started at 0652 h with the first line ashore at the Freyberg Wharf B in Auckland. The Co-Chief Scientists, IODP JRSO staff, and two CDEX technical engineers moved onto the ship around 0900 h. IODP JRSO technical staff conducted crossover with their Expedition 375 counterparts. Expedition 375 and 376 Co-Chief Scientists’ interviews with Radio New Zealand and a tour of the ship took place as scheduled. Initial loading of incoming freight began.