IODP Expedition 395C

Reykjanes Mantle Convection and Climate: Crustal Objectives

Daily Science Report for 31 July 2021

Location: Hole U1564C (59°51.0374′N, 23°16.0087′W; water depth 2208.1 mbsl; proposed Site REYK-2A)

Science Update: The drill string was run to a depth of 2220.0 mbsl to spud Hole U1564A, ~20 m west of the site coordinates. The exact site coordinates are to be reserved for future reentry system and casing installation during Expedition 395. Hole U1564A was initiated at 0245 h and Core U1564A-1H recovered a full core, prohibiting the establishment of the seafloor depth. The ship offset 20 m to the east—directly over the site coordinates—and Hole U1564B was spudded at 0342 h. Core U1564B-1H recovered 7.22 m of sediment, placing the seafloor at 2207.9 mbsl. Coring continued through Core 3H when the error in the ship’s offset was noted and operations at Hole U1564B were terminated. The bit cleared the seafloor at 0630 h, ending Hole U1564B. The ship was offset 20 m west, over the Hole U1564A coordinates, and Hole U1564C was spudded at 0707 h. The seafloor depth was calculated at 2208.1 mbsl, based on the recovery of Core U1564C-1H (7.02 m). Coring continued with the APC system recovering Cores 2H–17H (7.0–159.0 mbsf). Core 17H required significant overpull (90,000 lb) to release the core barrel from the sediment. Coring with the full-length APC was terminated and the crew began making up the HLAPC barrels.

All APC cores were oriented using the Icefield MI-5 tool. Formation temperature measurements were taken on Cores U1564C-4H, 7H, 10H, 13H, and 15H; however, the APCT-3 tool flooded on Core 4H and the data were not collected.

The JRSO technical staff continue to process samples in the laboratories. Because of the time constraints imposed by the single day of transit from the site to port, laboratory measurements were reduced for Site U1564. Cores U1564A-1H, U1564B-1H to 3H, and U1564C-1H to 17H were measured on the whole-round and the section half track systems. Headspace gas samples for safety monitoring and paleontology samples for postcruise biostratigraphy were collected on the catwalk. No other shipboard samples were collected from these cores. The whole-round core sections were immediately scanned without thermal equilibration on the Whole-Round Multisensor Logger and the Natural Gamma Radiation Logger. After being split, the section halves were imaged and measurements for color reflectance and point magnetic susceptibility were collected. Finally, the section halves were scanned on the SRM at 5 cm resolution using three demagnetization steps.

Cores U1564A-1H, U1564B-1H, and U1564C-1H are composed of clay to silt with brown, gray, and light gray banding. Cores U1564B-2H to 3H and U1564C-2H to 6H are a light gray to gray clay to silt. Within Core U1564C-7H, the sediment transitions from a lighter gray to a dark gray. From Core U1564C-8H to 17H, the clay to silt sediment shows gray to dark gray banding. Foraminifers can be seen on the split core surfaces and dropstones are occasionally observed. Methane values for these cores are under 3 ppmv.

Daily Science Report for 30 July 2021

Location:

Hole U1563B (60°11.9946′N, 27°59.9996′W; water depth 1417.8 mbsl; proposed Site REYK-11A)
Site U1564 (59°51.0377′N, 23°16.0071′W; proposed Site REYK-2A)

Science Update: The downhole wireline logging tools were put away and the drill pipe pulled up. The end of the pipe cleared the seafloor at 0105 h and the rotary table at 0513 h. The thrusters were raised and the vessel began the 144 nmi transit to Site U1564 (proposed Site REYK-2A) at 0518 h, ending Site U1563. The ship arrived on site at 1748 h. The APC/XCB BHA was made up and the drill string advanced to a depth of 1974 mbsl.

The JRSO technical staff began cleaning the laboratory spaces and preparing for the end of the expedition.

Daily Science Report for 29 July 2021

Location: Hole U1563B (60°11.9946′N, 27°59.9996′W; water depth 1417.8 mbsl; proposed Site REYK-11A)

Science Update: The drill pipe was pulled up to a depth of 87.6 mbsf in preparation for downhole logging operations. The triple combo tool string was assembled and deployed at 0410 h. The tool made two passes of the borehole, reaching a depth of 313.9 mbsf. At 0900 h, the triple combo reached the rig floor and was broken down. The second logging tool run was the VSI. At 1045 h, the VSI tool was deployed and the protected species observation protocols began. Whales were sighted in the area, delaying the start of operations. Once it was deemed safe to fire the air guns, the VSI was lowered to three stations: 283.9, 292.9, and 308.9 mbsf. Only the bottom two stations recorded successful measurements. At 1652 h, the protected species observation watch ended and the tools were pulled out of the hole, reaching the rig floor at 1810 h. After the VSI tool was broken down, the FMS-sonic tool string was assembled and deployed at 1935 h. The FMS-sonic tool descended to 311.0 mbsf and recorded resistivity images of the borehole. The tools were pulled up to the rig floor at 2325 h and the day ended while breaking down the FMS-sonic tool string.

The JRSO technical staff continued to process samples in the laboratories. Samples were collected for ICP-AES analysis and for thin sections.

Daily Science Report for 28 July 2021

Location: Hole U1563B (60°11.9946′N, 27°59.9996′W; water depth 1417.8 mbsl; proposed Site REYK-11A)

Science Update: Coring continued with Cores U1563B-25R to 32R advancing from 417.8 to 456.6 mbsf with an average ROP of 4 m/h. These cores recovered 8.4 m of basalt (22%). Following each core, the crew cleaned the hole with high-viscosity mud due to deteriorating hole conditions. After Core 32R was recovered, the drill pipe became stuck in the hole and was unable to rotate, circulate, or move. Coring operations were terminated and after ~1.5 h, the pipe was freed and the drill string was pulled up to a depth of 363.9 mbsf. The hole was prepared for downhole logging operations with another high-viscosity mud sweep. The rotary shift tool was deployed to release the drill bit and allow logging tools to exit the drill pipe. The RCB drill bit was released in the hole at 2325 h.

The JRSO technical staff continued to process cores and samples in the laboratories. Cores U1563B-25R to 32R were run through the whole-round and section half track systems. These cores are composed of dark gray basalt with vesicles and calcite veins. The basalts have some brown staining and contain infilled vesicles. Cores 26R and 27R contain intercalated carbonate beds.

Daily Science Report for 27 July 2021

Location: Hole U1563B (60°11.9946′N, 27°59.9996′W; water depth 1417.8 mbsl; proposed Site REYK-11A)

Science Update: Coring continued with Cores U1563B-15R to 24R advancing from 369.3 to 417.8 mbsf with an average ROP of 4 m/h. These cores recovered 15.66 m of basalt (32%).

The JRSO technical staff continued to process cores and samples in the laboratories. Cores U1563B-15R to 24R were run through the whole-round and section half track systems. These cores are composed of dark gray basalt with vesicles and calcite veins. The basalts have some brown staining and contain infilled vesicles. Core 15R contains intercalated carbonate beds and Cores 15R and 17R contain carbonate pieces with brecciated clasts of basalt.

Daily Science Report for 26 July 2021

Location: Hole U1563B (60°11.9946′N, 27°59.9996′W; water depth 1417.8 mbsl; proposed Site REYK-11A)

Science Update: Coring continued with Cores U1563B-6R to 14R advancing from 325.8 to 369.3 mbsf with an average ROP of 2.9 m/h. These cores recovered 16.81 m of basalt (40%).

The JRSO technical staff continued to process cores and samples in the laboratories. Cores U1563B-6R to 14R were run through the whole-round and section half track systems. These cores are composed of dark gray basalt with vesicles and calcite veins. The basalts have some brown staining and contain infilled vesicles. Thin intercalated carbonate beds are present in Cores 7R–9R and 14R.

Daily Science Report for 25 July 2021

Location: Hole U1563B (60°11.9946′N, 27°59.9996′W; water depth 1417.8 mbsl; proposed Site REYK-11A)

Science Update: Hole U1563B was advanced without coring to a depth of 301.4 mbsf. The center bit was retrieved and Cores U1563B-2R to 5R advanced from 301.4 to 325.8 mbsf. The sediment/ basement interface was encountered at ~315 mbsf, but was not preserved in Core 3R. While coring Core 5R, the wind increased to sustained speeds of 35 kt, gusting up to 45 kt, and the vessel began waiting on weather at 0800 h. It was noted that there was an unusual noise emanating from a transformer for three of the thrusters. To troubleshoot the issue, the three affected thrusters needed to be shut down. The vessel resumed operations at 1330 h once the wind speeds died down. Core 5R was recovered and the drill string pulled up 90 mbsf to work on the thrusters. It was discovered that the insulation around the cables going into the transformer was loose. Once this was repaired, the ship was able to resume operations at 1845 h. The crew deployed a wash barrel into the BHA and lowered the bit to 325.8 mbsf. After a high-viscosity mud sweep to clean the hole, the wash barrel was retrieved and a core barrel was deployed for Core 6R.

The JRSO technical staff continued to process cores and samples in the laboratories. Cores U1563B-2R to 5R were run through the whole-round and section half track systems. Core 2R contains 0.54 m of carbonate ooze with basalt clasts. Cores 3R to 5R are composed of dark gray basalt with vesicles and calcite veins. Thin intercalated carbonate beds are present in these cores.

Daily Science Report for 24 July 2021

Location:

Hole U1563A (60°11.9985′N, 28°00.0209′W; water depth 1417.8 mbsl; proposed Site REYK-11A)
Hole U1563B (60°11.9946′N, 27°59.9996′W; water depth 1417.8 mbsl; proposed Site REYK-11A)

Science Update: Coring continued with Core U1563A-49X advancing from 326.6 to 327.6 mbsf into the basement. Following Core 49X, the drill string was pulled out of the hole. The bit cleared the seafloor at 0400 h and the rotary table at 0715h, ending Hole U1563A. A total of 334.98 m of core was recovered from Hole U1563A (102% core recovery).

The ship was offset 21 m east of Hole U1563A and the RCB BHA was made up with a C-7 RCB drill bit. The drill string was made up and deployed to 1403 mbsl. Prior to initiating Hole U1563B, 115 ft of drill line was removed as part of regular maintenance. The center bit was dropped into the RCB bit and Hole U1563B was spudded at 1605 h. By midnight the bit had completed 279 m of the ~300 m drilling advance without core recovery.

The JRSO technical staff continued to process cores and samples in the laboratories. Cores U1563A-48X to 49X were run through the whole-round track systems and Cores 38F to 49X were split and run through the section half track systems. Cores 38F and 44F contain light gray to gray clay and silt with intervals of fine sand. Core 40F and the tops of Cores 41F and 43F contain brown, unconsolidated fine sand. Within Core 45F, the lithology transitions to a light gray silt and clay with gray and green mottling. This extends down to Core 47F where there is a sharp transition to yellow to white calcareous ooze. Core 47F contains three large (~3 cm) basalt clasts. The calcareous ooze extends to the basalt basement found in Section 48X-CC. Core 49X is dark gray basalt with intercalated carbonate beds.

Daily Science Report for 23 July 2021

Location: Hole U1563A (60°11.9985′N, 28°00.0209′W; water depth 1417.8 mbsl; proposed Site REYK-11A)

Science Update: The day began while replacing the piston rods on the APC core barrel. Once that was completed, Cores U1563A-17H to 21H (149.4–197.4 mbsf) were recovered. APC refusal was reached at Core 21H, when after the core barrel became stuck in the sediment, it required 130,000 lb of overpull to release the barrel from the formation. The HLAPC was deployed for Cores 22F to 47F (197.4–319.6 mbsf) and was switched out for the XCB coring system as the bit neared the estimated depth of the basement. Core 48X (319.6–326.6 mbsf) recovered the sediment/basement interface and the depth of basement at Hole U1563A was encountered at 326.4 mbsf. Catwalk sampling included interstitial water and paleontology whole-round samples and syringes for microbiology and headspace gas analyses.

The JRSO technical staff continued to process cores and samples in the laboratories. Cores 17H to 47F were run through the whole-round track systems and Cores 13H to 37F were split and run through the section half track systems. Cores 13H to 37F (111.9–272.5 mbsf) consist of clay and silt that are gray or display alternating gray and dark gray banding. Cores 13H, 17H, and 19H each contain a ~20 cm thick coarse sand bed.

Daily Science Report for 22 July 2021

Location:

In transit to Site U1563 (60°11.9964′N, 28°00.000′W; proposed Site REYK-11A)
Hole U1563A (60°11.9985′N, 28°00.0209′W; water depth 1417.8 mbsl; proposed Site REYK-11A)

Science Update: The vessel completed the remaining 23 nmi of the 39 nmi transit to proposed Site REYK-11A (Site U1563). The thrusters were lowered at 0212 h and the ship entered dynamic positioning mode at 0235 h, marking the start of Site U1563. The APC/XCB BHA was made up and the drill string deployed to 1415.7 mbsl. Hole U1563A was spudded at 0800 h and Core U1563A-1H recovered 7.4 m of sediment, placing the seafloor at 1417.8 mbsl. Cores 2H to 16H advanced to 149.9 mbsf, with 105% core recovery. During the collection of Core 16H, the core barrel became detached from the sinker bars and GS overshot tool when the shear pin in the GS overshot tool evidently failed. The sinker bars and GS overshot tool were recovered, the GS overshot tool replaced, and the core barrel retrieved. However, the APC piston rods twisted while the core barrel was in the BHA and the remainder of the day was spent replacing the rods. All of the APC cores were taken using nonmagnetic core barrels and were oriented with the Icefield MI-5 tool. Formation temperature measurements were collected on Cores 4H, 7H, 10H, and 13H. Catwalk sampling included interstitial water and paleontology whole-round samples, and syringes for microbiology and headspace gas analyses.

The JRSO technical staff continued to process cores and samples in the laboratories. Cores 1H to 16H were run through the whole-round track systems and Cores 1H to 12H were run through the section half track systems. The cores contain clay and silt with occasional fine sand beds and dropstones. Core 1H alternates between brown and gray layers and Cores 2H to 12H show light gray to dark gray banding. Methane values range from 0.4 to 2.15 ppmv.

Daily Science Report for 21 July 2021

Location:

Hole U1554F (60°7.5136′N, 26°42.1140′W; water depth 1870 mbsl; proposed Site REYK-6A)
In transit to Site U1563 (60°11.9964′N, 28°00.000′W; proposed Site REYK-11A)

Science Update: The vessel completed the 6.1 nmi transit in dynamic positioning mode to Hole U1554F at 0730 h. The subsea camera was deployed and the drill pipe was lowered to 1836 mbsl. The drill pipe was positioned over the reentry cone and reentered Hole U1554F at 0930 h. The subsea camera was retrieved and pipe was run to a depth of 68.5 mbsf, within the casing string, in preparation for downhole logging with the VSI tool. At ~1030 h, fog had formed around the vessel and reduced visibility. The vessel waited on the fog to clear and at 1250 h the VSI was deployed to the base of the casing string (602 mbsf), the air guns were set in the water, and the protected species observation protocols were initiated. Nearly immediately, whales were spotted within the exclusion zone, which delayed the start of the VSI operations. After two hours of tracking whales in the vicinity of the vessel, foggy conditions reduced visibility, prohibiting the continuation of protected species observation watch. With the fog forecasted to worsen throughout the evening and into the next day, the planned VSI operations were cancelled at 1600 h in favor of coring at the next site. The VSI was pulled from the drill pipe and the tool reached the rig floor at 1700 h. While retrieving the tool string, visibility briefly improved only to reveal that the whales had come closer to the ship. The drill pipe was pulled out of the hole and the end of the pipe cleared the seafloor at 1840 h and the rig floor at 2210 h. The rig floor was secured for transit and the thrusters were raised. The vessel began the 39 nmi transit to Site U1563 (proposed Site REYK-11A) at 2236 h, ending Hole U1554F. By the end of the day, the vessel had traveled 16 nmi.

The JRSO technical staff continue to process samples in the laboratories.

Daily Science Report for 20 July 2021

Location:

Hole U1562B (60°6.2993′N, 26°30.1026′W; water depth 2003 mbsl; proposed Site REYK-3B)
In transit to Hole U1554F (proposed Site REYK-6A)

Science Update: The day began with the continuation of downhole logging operations. After the triple combo tool string was laid out, the FMS-sonic was made up and deployed at 0100 h. Following two passes that extended to the base of the hole, the FMS-sonic was pulled from the hole and reached the rig floor at 0645 h. The next logging run used the VSI tool. The Protected Species Observation (PSO) protocols began at 0730 h and the JRSO technical staff ramped up the air guns starting at 0834 h. The VSI was lowered to the base of the hole and a total of four depth stations were completed, three within the basement section and one just above the sediment/basement interface. The VSI could not be successfully run throughout the sedimentary section due to the wide diameter of the borehole. Following the VSI run, the air guns were put away and tool reached the rig floor at 1320 h. The final logging run, using the UBI tool, began at 1445 h. The UBI made two passes of the basement section, acquiring 360° borehole images. The UBI was recovered at the rig floor at 2130 h. The drill string was pulled out of the hole to a depth of ~1489 mbsl and the ship began the transit in dynamic positioning mode to Hole U1554F at 2355 h, ending Site U1562.

The JRSO technical staff continue to process samples in the laboratories.

Daily Science Report for 19 July 2021

Location: Hole U1562B (60°6.2993′N, 26°30.1026′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: Coring continued with Cores U1562B-29R to 32R advancing from 542.1 to 561.5 mbsf at a rate of 2.6 m/h. A total of 6.94 m of core was recovered over this interval (36%). Following coring, the RST was run to release the bit into the bottom of the hole. The drill string was pulled up and the end of the pipe was set at a depth of 89 mbsf in preparation for logging. The triple combo logging tool string was made up and deployed at 1755 h. After completing two successful passes of the entire hole, the tools were retrieved and reached the rig floor at 2310 h. The day ended as we were laying out the triple combo tool string.

The JRSO technical staff continued to process cores and samples in the laboratories. Cores U1562B-29R to 32R were run through the whole-round and split core track systems. These cores are composed of gray to brown basalt that displays varying degrees of alteration with infilled vesicles, calcite veins, and staining. Many of the core pieces have glass rinds.

Daily Science Report for 18 July 2021

Location: Hole U1562B (60°6.2993′N, 26°30.1026′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: Coring continued with Cores U1562B-21R to 28R advancing from 503.3 to 542.1 mbsf at a rate of 2.3 m/h. A total of 15.53 m of core was recovered over this interval (40%).

The JRSO technical staff continued to process cores and samples in the laboratories, and chemistry measurements of samples from Hole U1562A are ongoing. Cores U1562B-20R to 28R were run through the whole-round and split core track systems. These cores are composed of gray to brown basalt, which displays varying degrees of alteration with infilled vesicles, calcite veins, and staining. Many of the core pieces have glass rinds.

Daily Science Report for 17 July 2021

Location: Hole U1562B (60°6.2993′N, 26°30.1026′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: The day began with the rig floor crew pulling up the drill pipe to change the drill bit. An FFF was deployed at 0220 h to allow for the reentry of Hole U1562B. The bit cleared the seafloor at 0312 h and the rotary table at 0708 h. A C-7 RCB coring bit was made up to the BHA and the crew assembled the drill string. The subsea camera was deployed at 1130 h to observe the hole reentry, which occurred at 1450 h. The subsea camera was retrieved and the drill string advanced to 500.7 mbsf. After cleaning the hole with a high-viscosity mud sweep, Core U1562B-20R advanced from 500.7 to 503.3 mbsf with 75% core recovery.

The JRSO technical staff continued to process cores and samples in the laboratories, and chemistry measurements of samples from Hole U1562A are ongoing.

Daily Science Report for 16 July 2021

Location: Hole U1562B (60°6.2993′N, 26°30.1026′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: Coring continued with Cores U1562B-13R to 19R advancing from 470.2 to 500.7 mbsf at a rate of 2 m/h. A total of 14.88 m of core was recovered over this interval (49%). While coring Core 19R, the penetration rate dropped to 1 m/h and there was erratic torque on the bit. It was suspected that the drill bit was damaged and the rig floor crew began pulling the pipe out of the hole.

The JRSO technical staff continued to process cores and samples in the laboratories. Cores U1562B-13R to 19R were run through the whole-round and split core track systems. These cores are composed of basalt, which displays varying degrees of alteration with infilled vesicles, calcite veins, and staining. Core 14R contains a 0.6 m long interval of nannofossil ooze within the basalt flows. Intercalated carbonate beds are found in Cores 15R to 19R.

Chemistry measurements of samples from Hole U1562A are ongoing. Total organic carbon has an average value of 0.59 wt% with a maximum concentration of 5.23 wt% at 413 mbsf.

Daily Science Report for 15 July 2021

Location: Hole U1562B (60°6.2993′N, 26°30.1026′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: Coring continued with Cores U1562B-6R to 12R advancing from 460.5 to 470.2 mbsf at a rate of 1.8 m/h. A total of 17.17 m of core was recovered over this interval (51%).

The JRSO technical staff continued to process cores and samples in the laboratories. Cores U1562B-6R to 12R were run through the whole-round and split core track systems. These cores are composed of basalt, which displays varying degrees of alteration with infilled vesicles, calcite veins, and staining.

Chemistry measurements of samples from Hole U1562A are ongoing.

Daily Science Report for 14 July 2021

Location: Hole U1562B (60°6.2993′N, 26°30.1026′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: The drill string was lowered and Hole U1562B was spudded at 0320 h. The hole was advanced without coring to a depth of 408.1 mbsf. The center bit was recovered and an RCB core barrel was deployed. Cores U1562B-2R to 5R were advanced from 408.1 to 436.8 mbsf, recovering 16.57 m of sediment and basalt (58%). The sediment/basement interface was recovered in Core 4R at a depth of 429.1 mbsf. Whole-round samples for postcruise microbiology analysis were routinely collected.

The JRSO technical staff continue to process cores and samples in the laboratories. Cores U1562B-2R to 5R were run through the whole-round and split core track systems. Core 2R through Section 4R-1 contain greenish gray, fine-grained, carbonate-rich, bioturbated sediment. Section 4R-2 to Core 5R are composed of dark gray vesicular basalt. The basalt displays varying degrees of alteration with infilled vesicles, calcite veins, and staining.

The sediments of the uppermost 150 m of Hole U1562A contain little carbonate, with values ranging from 0.04 to 33 wt%. Within the interval of 150–300 mbsf, carbonate values range from 4 to 65 wt%. Below 300 mbsf, values are consistently elevated with a maximum of 78 wt%. Pore water alkalinity increases downhole in Hole U1562A from ~2.5 mM at the top of the hole to a maximum value of 7.5 mM at 223 mbsf. Below 223 mbsf, alkalinity decreases to ~3.5 mM above the sediment/basement interface (~427 mbsf).

Daily Science Report for 13 July 2021

Location: Hole U1562A (60°6.3030′N, 26°30.1245′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: Coring continued with Cores U1562A-60X to 64X advancing from 380.6 to 429.1 mbsf with 49% core recovery. After coring Core 64X, the XCB cutting shoe was severely damaged and slightly melted and the base of the core catcher contained basalt. Core 65X was deployed to ensure that the bit had reached basement and advanced 0.7 m over an hour. Core 65X contained 0.68 m of basalt, confirming a basement depth of 429.1 mbsf. Samples for interstitial water, microbiology, and gas analyses were routinely collected on the catwalk. The final depth of Hole U1562A was 429.8 mbsf. A total of 411 m of core was recovered over a 429.8 m interval (96%) from Hole U1562A.

The drill string was pulled from the hole, with the bit reaching the seafloor at 1535 h. Hole U1562A ended when the bit reached the rotary table at 1935 h. An RCB BHA was made up and the day ended with the drill string being lowered to start Hole U1562B.

The JRSO technical staff continued to process cores and samples in the laboratories. Cores U1562A-60X to 65X were run through the whole-round track systems and Cores 46F to 65X were split and measured on the split core track systems. Cores 46F to 54F contain alternating gray to dark gray clays and silts with some intervals of fine sand. Bioturbation and soft sediment deformation are present in these cores. Core 55F captures a transition between the overlying clays and silts to a finer grained, carbonate-rich, greenish gray sediment with abundant bioturbation that continues to Core 64X. Cores 58X and 60X contain large (~5 cm) basalt clasts. The lithology in Core 64X transitions from the greenish gray, bioturbated, fine-grained sediment to a white carbonate ooze. Section 64X-CC and Core 65X are composed of dark gray, vesicular to avesicular basalt that contains white to green veins and infilled vesicles. The XCB cores are fractured and disturbed. Hydrocarbon gases in Hole U1562A are present in very low concentrations. Methane peaks at 2.61 ppmv at ~223 mbsf.

Daily Science Report for 12 July 2021

Location: Hole U1562A (60°6.3030′N, 26°30.1245′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: Coring continued with Cores U1562A-29F to 57F advancing from 224.9 to 361.2 mbsf with 103% core recovery. Core 57F experienced significant overpull and was drilled over with the drill string to release the core. The XCB core barrels were made up and coring continued with Cores 58X and 59X (361.2–380.6 mbsf). Core recovery for the XCB cores was 69%. Samples for interstitial water, microbiology, and gas analyses were routinely collected on the catwalk.

The JRSO technical staff continue to process cores and samples in the laboratories. Cores 29F to 59X were run through the whole-round track systems and Cores 18H to 45F were split and measured on the split core track systems. Cores 18H to 34F are composed of clay and silt that alternate between gray and dark gray and contain intervals of fine sand. Within Core 35F is a transition from the overlying gray clay and silt to a lighter gray clay. This core contains soft sediment deformation. Cores 36F to 45F range from light gray to dark gray clay with bioturbation. Core 43F displays soft sediment deformation. The tops of some of the cores are highly disturbed, likely resulting from the heave of the ship.

Daily Science Report for 11 July 2021

Location: Hole U1562A (60°6.3030′N, 26°30.1245′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: Coring continued with Cores U1562A-3H to 21H advancing from 11.5 to 192.0 mbsf. Core 21H experienced significant overpull and was drilled over with the drill string to release the core. The half-length APC (HLAPC) core barrels were made up and coring continued with Cores 22F–28F (192.0–224.9 mbsf) with 4.7 m advances. Core recovery for Hole U1562A was 104%. All of the APC cores were oriented and formation temperature measurements using the APCT-3 tool were collected for Cores 4H, 7H, 10H, and 13H. Samples for interstitial water, microbiology, and gas analyses were routinely collected on the catwalk.

The JRSO technical staff continued to process cores and samples in the laboratories. Cores 1H to 28F were run through the whole-round track systems and Cores 1H to 17H were split and measured on the split core track systems. Cores 1H to 4H alternate between brown and gray sediments. Cores 5H to 15H are dark gray and Cores 16H to 17H alternate between green and dark gray sediment. The sediments are primarily clay and silt, with intervals of fine-grained sand. Dropstones are interspersed in the core sections.

Daily Science Report for 10 July 2021

Location:

Hole U1554F (60°7.5136′N, 26°42.1140′W; water depth 1870 mbsl; proposed Site REYK-6A)
Hole U1562A (60°6.3027′N, 26°30.1256′W; water depth 2003 mbsl; proposed Site REYK-3B)

Science Update: At daybreak, visibility had worsened and conditions were not forecasted to improve until evening. The decision was made to abandon the VSI logging run and begin operations at proposed Site REYK-3B. The drill pipe was pulled up and cleared the seafloor at 0755 h, ending Hole U1554F and Site U1554. The vessel began the 6.1 nmi transit to proposed Site REYK-3B under dynamic positioning mode. The crew continued to pull up the pipe with the end of the pipe clearing the rotary table at 1130 h. At 1306 h, the vessel arrived at Site U1562 (proposed Site REYK-3B) and the APC/XCB BHA was made up. The drill pipe was run to 1996 mbsl to take the first APC core. Core U1562A-1H recovered the mudline and 2.08 m of core, establishing a seafloor depth of 2003 mbsl. Coring continued with the recovery of Core 2H from a depth of 11.5 mbsf.

The JRSO technical staff continue to process cores and samples in the laboratories.