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IODP Expedition 395C

Reykjanes Mantle Convection and Climate: Crustal Objectives


Daily Science Report for 30 June 2021

Location: Hole U1554F (60°7.5136′N, 26°42.1140′W; water depth 1870 mbsl; proposed Site REYK-6A)

Science Update: The BHA for drilling in the casing string was made up and the HRT running tool and reentry cone were assembled. At 0638 h, the HRT reentry system was deployed through the moonpool. The casing and drill string were run to a depth of 1552 mbsl and the subsea camera was deployed to observe the casing operations. The drill string continued to be lowered and at 1345 h Hole U1554F was spudded. As of midnight, the bit had advanced 275 m into the seafloor, with a target depth of 602 mbsf for the end of the casing.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 32X to 42X were measured using the SRM. Pore water and sediment chemistry measurements are ongoing.


Daily Science Report for 29 June 2021

Location: Hole U1554F (60°7.5133′N, 26°42.1337′W; water depth 1870 mbsl; proposed Site REYK-6A)

Science Update: The day began with pulling up the pipe from Hole U1554E. At 0245 h the bit cleared the rotary table, ending the hole. The ship was positioned over the Hole U1554F coordinates and the rig floor crew began assembling the casing and reentry system. The mudskirt of the reentry system was moved over the moonpool and the hydraulic release tool (HRT) was made up and racked in the derrick. A 602.3 m long casing string, composed of 52 joints of 10¾ inch casing, was assembled. The HRT was attached to the casing and lowered to the mudskirt. The HRT was then detached and put back into the derrick. A drilling assembly with a mud motor, underreamer, and bit was assembled and tested in the moonpool. The first mud motor rotated too freely and was replaced with a second mud motor. After successfully testing that the underreamer arms open appropriately, the crew began making up the BHA.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores U1554E-24X to 31X were measured using the SRM. Pore water and sediment chemistry measurements are ongoing.


Daily Science Report for 28 June 2021

Location: Hole U1554E (60°7.5235′N, 26°42.1324′W; water depth 1870 mbsl; proposed Site REYK-6A)

Science Update: Downhole wireline logging continued with the triple combo tool string making two passes of the borehole. The tool string was able to descend to the base of the hole (~647 mbsf). The first attempt to pull the triple combo through the bit and into the drill pipe occurred at 0115 h. The lockable float valve (LFV) at the bit had closed, preventing the tool string from reentering the pipe. After several hours of pumping seawater and rotating the drill string, the triple combo was pulled past the LFV and the tools reached the surface at 0845 h. The FMS-sonic was assembled and deployed at 1120 h. A go-devil was attached to the top of the tool string to lock open the LFV. After two passes of the borehole, the FMS-sonic was unable to pass through the LFV and back into the pipe. After more pumping, the tools were successfully recovered and the FMS-sonic tool string reached the rig floor at 2055 h. Following logging operations the drill string was pulled out of the hole with the bit clearing the seafloor at 2210 h. The remainder of the day was spent pulling up the pipe and BHA.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 58X to 62X were split, imaged, and measured for point magnetic susceptibility and color reflectance. Cores 19X to 23X were measured using the SRM. The cores were sampled for paleontology and moisture and density analyses.

Cores 57X to 60X contain sediments that alternate between light green to dark gray with varying amounts of calcium carbonate and clay content. Sharp erosional contacts and burrows are observed in these cores. Core 61X transitions from the dark gray material to a light green and white nannofossil ooze. The basement was recovered in Core 62X and is composed of basalt alternating with carbonate. Pore water alkalinity decreases from 12.5 mM at ~350 mbsf to 2.3 mM at the base of the hole.


Daily Science Report for 27 June 2021

Location: Hole U1554E (60°7.5235′N, 26°42.1324′W; water depth 1870 mbsl; proposed Site REYK-6A)

Science Update: Coring continued in Hole U1554E from Core 56X to 62X (586.9–647.7 mbsf), with 50.5 m of core recovered (83%). Basement was encountered at ~647 mbsf while drilling Core 62X; the core contained 2.6 m of basalt interlayered with carbonate. After reaching the basement and a final depth of 647.7 mbsf, Hole U1554E was prepared for downhole wireline logging operations. The hole was cleaned and displaced with mud and the drill string pulled up to 72.8 mbsf. The triple combo tool string was made up and run in the hole at 2100 h.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 56X to 62X were run through the whole-round physical properties tracks and Cores 44X to 57X were split, imaged, and measured for point magnetic susceptibility and color reflectance. Cores 14H to 18X were measured using the SRM. We are collecting routine samples for interstitial waters, gas, microbiology, paleontology, and moisture and density analyses.

The cores contain dark gray clay and silt with dropstones, and pyritized gastropods are present. Core 56X contains a formation change to lighter material with soft sediment deformation and erosional surfaces. The XCB cores have prevalent biscuiting from the coring process.


Daily Science Report for 26 June 2021

Location: Hole U1554E (60°7.5235′N, 26°42.1324′W; water depth 1870 mbsl; proposed Site REYK-6A)

Science Update: Coring at Hole U1554E continued from Core 42X to 55X (451.1–586.9 mbsf), with 102.35 m of core recovered (75%). XCB coring will continue until the basement is reached, which is estimated at 700 mbsf.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 35X to 55X were run through the whole-round physical properties tracks and Cores 25X to 43X were split, imaged, and measured for point magnetic susceptibility and color reflectance. Cores 9H to 13H were measured using the SRM. We are collecting routine samples for interstitial water, gas, microbiology, paleontology, and moisture and density analyses.

The cores contain dark gray clay and silt with dropstones, and pyritized gastropods are present. The XCB cores have prevalent biscuiting.


Daily Science Report for 25 June 2021

Location: Hole U1554E (60°7.5235′N, 26°42.1324′W; water depth 1870 mbsl; proposed Site REYK-6A)

Science Update: Coring at Hole U1554E continued with Core 17H at a depth of 208.8 mbsf. After the core barrel was shot, it could not be pulled out of the sediment using the core winch line. The barrel was drilled over using the drill string to free the core. Following Core 17H, the XCB system was deployed. Cores 18X to 41X were collected (218.3–451.1 mbsf) with 98% core recovery. The Co-Chief Scientists and Expedition Project Manager hosted a review meeting of Site U1555 for the science party. The meeting reviewed the site operations, coring results, and some of the datasets.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 12H to 34X were run through the whole-round physical properties tracks and Cores 10H to 24X were split, imaged, and measured for point magnetic susceptibility and color reflectance. Cores 4H to 8H were measured using the SRM.

Catwalk sampling for interstitial pore water and microbiology began at Core 31X (~350 mbsf). The overlying sedimentary section will be sampled for these analyses during Expedition 395 when a sailing science party is available to assist with the measurements.

The cores contain dark gray clay and silt with intervals that are light gray and light greenish gray. The APC cores display mottling and bioturbation. Dropstones are occasionally observed. Foraminifers and biogenic silica can be seen in the split core sections using a hand lens. The XCB cores have prevalent biscuiting.

Following 14 d of isolation at sea, shipboard COVID-19 safety protocols were lifted at 1000 h.


Daily Science Report for 24 June 2021

Location: Hole U1554E (60°7.5235′N, 26°42.1324′W; water depth 1870 mbsl; proposed Site REYK-6A)

Science Update: The vessel arrived at Site U1554 early in the day. The ship’s thrusters were lowered at 0124 h and the vessel switched to dynamic positioning mode at 0136 h. The BHA and drill string were made up and run to the seafloor. At 0754 h Hole U1554E was spudded and drilled without recovery to 66.3 mbsf, based on initial coring operations conducted during Expedition 384 in July 2020. Coring using the APC advanced from 66.3 to 208.8 mbsf (Cores 2H–16H). A total of 148 m of sediment was cored, with 104% core recovery. The cores were expanding upon arrival on the core receiving platform. Formation temperature measurements using the APCT-3 tool were collected on Cores 2H, 5H, 8H, and 11H.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 2H to 11H were run through the whole-round physical properties tracks and Cores 2H to 9H were split, imaged, and measured for point magnetic susceptibility and color reflectance. Cores 2H to 3H were measured using the SRM. Methane concentrations increased downhole from 0 to 11,000 ppm.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 23 June 2021

Location:

  • Hole U1555I (60°13.6897′N, 28°29.9984′W; water depth 1523.5 mbsl; proposed Site REYK-13A)
  • In transit to Site U1554 (proposed Site REYK-6A)

Science Update: The day began with working to free the triple combo logging tool string from Hole U1555I. After many attempts to pull the tools free using the Schlumberger logging line winch, the decision was made to lower the drill pipe over the tools to clear the obstruction. The drill pipe was lowered and the top of the triple combo was encountered at 183.5 mbsf, ~7 m below the sediment/basement interface. The obstruction in the hole was at 225.5 mbsf. The drill pipe was lowered until the obstruction was pushed past the base of the tool string. At 1015 h, the tool string was free and the rig floor crew began pulling the tools up using the core winch line. At 1400 h, the tools arrived at the rig floor and were disassembled. The drill pipe was pulled from the hole. At 1700 h the pipe cleared the seafloor and at 2015 h it cleared the rotary table. The vessel was secured for transit and the thrusters were raised at 2036 h, ending Hole U1555I. At the end of the day, the ship had completed 40 of the 54 nmi transit to proposed Site REYK-6A (Site U1554).

The JRSO technical staff are processing the cores and samples in the laboratories. Cores U1555I-27R to 41R were sampled for thin sections and ICP-AES measurements.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 22 June 2021

Location: Hole U1555I (60°13.6897′N, 28°29.9984′W; water depth 1523.5 mbsl; proposed Site REYK-13A)

Science Update: Cores 37R to 41R were cut from 353.3–376.5 mbsf. Core recovery significantly decreased in Cores 38R to 40R with only 10% of the basalt section retrieved. After reaching a depth of 376.5 mbsf, or 200 m into the basement, coring concluded at Hole U1555I. A total of 40 rotary core barrel (RCB) cores were recovered from Hole U1555I with 48% core recovery (77% sediment recovery and 45% basalt recovery).

Following core operations, the borehole was prepped for downhole wireline logging operations. A high-viscosity mud sweep was used to clean the hole of debris. The drill bit was dropped at the bottom of the hole and the drill pipe brought up to 75.6 mbsf. The triple combination logging tool string was assembled and deployed at 1720 h. The tool descended to the bottom of the hole and began taking measurements as it was pulled up the hole. The triple combo became stuck at ~220 mbsf and the remainder of the day was spent trying to free the tool string.

The JRSO technical staff are processing the cores and samples in the laboratories. All cores from Hole U1555I have been measured.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 21 June 2021

Location: Hole U1555I (60°13.6897′N, 28°29.9984′W; water depth 1523.5 mbsl; proposed Site REYK-13A)

Science Update: Cores 27R to 36R were cut from 304.8–353.3 mbsf with 25.35 m of basalt recovered (52%).

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 27R to 32R were processed in all of the laboratories. Cores 33R to 36R have been measured for physical properties and are awaiting scanning in the SRM.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 20 June 2021

Location: Hole U1555I (60°13.6897′N, 28°29.9984′W; water depth 1523.5 mbsl; proposed Site REYK-13A)

Science Update: The crew began pulling the drill string out of the hole after reaching 49 rotating h on the drill bit. At 0320 h a free-fall funnel (FFF) was deployed to allow for reentry into the hole. The subsea camera was deployed to observe the placement of the funnel and to ensure that the pipe did not move it out of position when the bit exited the hole. The bit cleared the seafloor at 0450 h, the subsea camera was retrieved, and the bit cleared the rotary table at 0930 h. After changing the drill bit, the drill string was reassembled and the subsea camera was deployed for the reentry of Hole U1555I. The FFF remained in position and the bit reentered Hole U1555I at 1605 h. After recovering the subsea camera, the center bit was dropped and the drill string advanced to 304.8 mbsf. Mud sweeps were used to clean the hole of debris. The day ended while we were cutting Core 27R.

The conductivity, temperature, and depth (CTD) sonde was deployed on the subsea camera frame to collect conductivity, temperature, and pressure measurements of the seawater.

The JRSO technical staff are processing the cores and samples in the laboratories. All cores collected thus far from Hole U1555I have been processed.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 19 June 2021

Location: Hole U1555I (60°13.6897′N, 28°29.9984′W; water depth 1523.5 mbsl; proposed Site REYK-13A)

Science Update: Coring continued from Core U1555I-18R to 26R (261.3–304.8 mbsf) with 46% recovery. Whole-round samples for postcruise microbiology research were collected every ~10 m. After cutting Core 26R, the drill bit reached 49 rotating h. The crew began preparations for changing the drill bit.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 18R to 26R, containing basalt, were run through the whole-round and section half track systems. Select pieces from Cores 11R to 22R were run through the SRM.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 18 June 2021

Location: Hole U1555I (60°13.6897′N, 28°29.9984′W; water depth 1523.5 mbsl; proposed Site REYK-13A)

Science Update: Coring continued from Core U1555I-11R to 17R (227.2–261.3 mbsf) with 53% recovery. Whole-round samples for postcruise microbiology research were collected every ~10 m.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 11R to 17R, containing basalt, were run through the whole-round and section half track systems. Select pieces from Cores 5R to 10R were run through the SRM. We finished measuring the XRD, sediment chemistry, and gas samples from Hole U1555H. Pore water alkalinity, pH, and ion chromatography (IC) measurements from this hole are also complete.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 17 June 2021

Location: Hole U1555I (60°13.6897′N, 28°29.9984′W; water depth 1523.5 mbsl; proposed Site REYK-13A)

Science Update: The day began with cutting Core U1555I-5R at a depth of 191.5 mbsf. Cores 5R and 6R recovered 7.5 m of basalt (39% recovery). Following Core 6R the crew ran mud sweeps to clean the hole. Beginning with Core 7R, the drill string was advanced ~5 m for each core. Cores 7R and 8R recovered 5.06 m of basalt (52% recovery). Additional mud sweeps were performed following Core 8R as hole conditions had again deteriorated. Cores 9R and 10R were collected with 46% core recovery to a depth of 227.2 mbsf. Whole-round samples for postcruise microbiology research were collected every ~10 m.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores 4R to 10R, containing basalt, were run through the whole-round and section half track systems. The whole-round core measurements include magnetic susceptibility, gamma ray attenuation (GRA) bulk density, and natural gamma radiation (NGR). The split cores are being imaged and measured for P-wave velocity, thermal conductivity, color reflectance, point magnetic susceptibility, and X-ray fluorescence (XRF) using a handheld device. Cores 2R to 4R were run through the SRM. Sample preparation and measurements for chemistry and XRD are underway.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 16 June 2021

Location: Hole U1555I (60°13.6897′N, 28°29.9984′W; water depth 1523.5 mbsl; proposed Site REYK-13A)

Science Update: The vessel continued to wait on weather until 0900 h. After lowering the drill string, Hole U1555I was initiated at 1005 h. The hole was drilled without recovery to 159.3 mbsf. Cores 2R and 3R were collected from 159.3 to 178.7 mbsf with 77% sediment recovery. Core 4R recovered 5.95 m of basalt from 178.7 to 185.39 mbsf (61% recovery).

The JRSO technical staff are processing the cores and samples in the laboratories. Cores U1555H-15H to 20X were run through the SRM. Cores U1555I-2R and 3R were measured using the whole-round and section half physical properties track systems. Sample preparation for chemistry and XRD is underway.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 15 June 2021

Location: Hole U1555I (60°13.6903′N, 28°29.9997′W; water depth 1523.6 mbsl; proposed Site REYK-13A)

Science Update: The crew continued to assemble the drill string for operations at Hole U1555I. At 0315 h the vessel began waiting on weather and spent the remainder of the day monitoring weather conditions. Winds picked up to over 30 kt with waves up to 5.5 m, inhibiting operations.

The JRSO technical staff are processing the cores and samples in the laboratories. Cores U1555H-10H to 14H were run through the SRM and demagnetized at six steps, up to 35 mT. Sample preparation for chemistry and XRD is underway.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 14 June 2021

Location: Hole U1555H (60°13.69242′N, 28°30.0239′W; water depth 1523.6 mbsl; proposed Site REYK-13A)

Science Update: The day began with the Siem Offshore crew continuing to free the core winch line from the oil saver sub in the top drive. After removing, cutting, and reheading the line, coring continued from Cores U1555H-16H to 18H (138 to 166.5 mbsf). The extended core barrel (XCB) system was deployed for the remaining cores. Core 19X was advanced 6 m to ensure that Core 20X would recover the sediment/basement interface, which was encountered at 176.5 mbsf. The final depth of Hole U1555H was 177.5 mbsf. The crew began tripping pipe and the bit cleared the seafloor at 1525 h. At 2000 h, the bit cleared the rotary table, ending Hole U1555H. The rotary core barrel (RCB) bottom-hole assembly (BHA) was made up and the drill string assembled. All advance piston corer (APC) cores were oriented using the Icefield MI-5 tool. A total of 180.06 m of core was recovered form Hole U1555H, with 101% recovery.

The JRSO technical staff are processing the cores and samples in the laboratories. Samples for interstitial water, microbiology, gas, and paleontology are being collected regularly. Cores 15H to 20X were scanned using the whole-round track systems. Cores 12H to 20X were split, imaged, and measured for point magnetic susceptibility and color reflectance. Whole-round and split core Sections 20X-3A to 5A were imaged using the X-ray imaging system. Cores 5H to 9H were run through the SRM and demagnetized at six steps, up to 35 mT. Intervals of core disturbance are present, likely caused by the heave of the ship.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 13 June 2021

Location: Hole U1555H (60°13.69242′N, 28°30.02395′W; water depth 1523.6 mbsl; proposed Site REYK-13A)

Science Update: After assembling the drill string, coring in Hole U1555H was initiated at 0650 h. Core U1555H-1H recovered a good mudline with 5 m of sediment, placing the seafloor depth at 1523.6 m below sea level (mbsl). Cores 1H to 10H were cored to 90.5 m below seafloor (mbsf) with 101% recovery. Following Core 10H, 150 m of the core winch line was cut to remove damaged portions. Coring continued with Cores 11H to 15H to a depth of 138 mbsf, with 97% recovery. The core winch line was again damaged when it got stuck in the oil saver sub on the top drive. The day ended with the Siem Offshore crew working on the core winch line. Formation temperature measurements were collected on Cores 4H, 7H, 10H, and 13H using the APCT-3. All cores were oriented using the Icefield MI-5 tool.

The JRSO technical staff are processing the cores and samples in the laboratories. Samples for interstitial water, microbiology, gas, and paleontology are being collected regularly. Cores 1H to 14H have been scanned on the whole-round track systems. Cores 1H to 11H have been split, imaged, and measured for point magnetic susceptibility and color reflectance. Cores 1H to 4H have been run through the superconducting rock magnetometer (SRM) and demagnetized at six steps, up to 35 mT. The split cores are gray to brown in color and contain occasional dropstones. Intervals of core disturbance are present, likely caused by the heave of the ship.

Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 12 June 2021

Location: Hole U1555H (60°13.6915′N, 28°30.0207′W; water depth 1523.6 mbsl; proposed Site REYK-13A)

Science Update: After a 312 nmi transit averaging 11.6 kt, the ship arrived at Site U1555 (proposed Site REYK-13A) at 1225 h. The thrusters were lowered and the vessel switched to dynamic positioning mode, beginning Hole U1555H at 1300 h. The crew began to assemble the drill collars until the weather deteriorated with winds blowing up to 40 kt. From 1645 to 2045 h the vessel was waiting on weather. After the wind died down, the crew continued to assemble the drill collars and make up the drill bit. Shipboard COVID-19 safety protocols are being followed.


Daily Science Report for 11 June 2021

Location: In transit to proposed site REYK-13A (Site U1555)

Science Update: The final member of the JRSO staff boarded the vessel in the morning and at 0852 h the pilot boarded the ship. After some difficulties with the mooring lines, the ship left the dock with the last line away at 0948 h. At 1000 h the pilot departed and the ship was underway to proposed site REYK-13A (Site U1555). The first lifeboat drill was held in the afternoon. Shipboard COVID-19 safety protocols are being followed and the vessel will arrive on site at ~1300 h on 12 June.


Daily Science Report for 10 June 2021

Location: Berth 10 Scarfabakki, Reykjavík, Iceland

Science Update: Port call activities continued for Expedition 395C. The ship took on more fuel and the food shipment was loaded. We held the pre-site meeting for proposed Sites REYK-13A and REYK-6A (Sites U1555 and U1554) to review the operations with the Co-Chief Scientists, the Schlumberger engineer, and the Siem Offshore crew. Shipboard COVID-19 safety protocols are being followed and the ship is scheduled to depart Reykjavík at 0900 h on 11 June.


Daily Science Report for 9 June 2021

Location: Berth 10 Scarfabakki, Reykjavík, Iceland

Science Update: The remaining 26 Expedition 395C staff and crew members boarded the vessel in the morning. Port call activities continued and the ship began taking on fuel. The JRSO staff assembled a weather wall around the catwalk in anticipation of cool temperatures and adverse weather conditions while at sea. Shipboard COVID-19 safety protocols are being followed and the ship is scheduled to depart Reykjavík at 0900 h on 11 June.


Daily Science Report for 8 June 2021

Location: Berth 10 Scarfabakki, Reykjavík, Iceland

Science Update: The majority of the Expedition 395C JRSO staff and ship’s crew moved onto the vessel in the morning. The remaining staff and crew, who arrived in Reykjavík a day later, continued to isolate in their hotel rooms following JRSO quarantine and testing procedures prior to boarding on 9 June. Port call activities continued. The ship is scheduled to depart Reykjavík on 11 June.


Daily Science Report for 7 June 2021

Location: Berth 10 Scarfabakki, Reykjavík, Iceland

Science Update: Port call activities continued with the loading and offloading of freight. Virtual crossover meetings between the ongoing and departing staff have been taking place to minimize in-person contact. The Expedition 395C JRSO team and ship’s crew continued to isolate in their hotel rooms in Reykjavík, following JRSO quarantine and testing procedures, prior to boarding on 8 June. The ship is scheduled to depart Reykjavík on 11 June.


Daily Science Report for 6 June 2021

Location: Berth 10 Scarfabakki, Reykjavík, Iceland

Science Update: Expedition 395C officially began at 0818 h on 5 June 2021. Port call activities continued with the loading of freight. The Expedition 395C JRSO team and ship’s crew continued to isolate in their hotel rooms in Reykjavík, following JRSO quarantine and testing procedures, prior to boarding on 8 June. The ship is scheduled to depart Reykjavík on 11 June.