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IODP Expedition 396

Mid-Norwegian Continental Margin Magmatism


Daily Science Report for 22 September 2021

Location: In transit on a heavy weather and seas avoidance course. Midnight position 66°8.50′N, 2°55.60′E.

Science Update: We continued navigating in a southwesterly direction to avoid the heaviest seas, changing course as needed to keep the seas on the bow. The heaviest seas (13–15 m wave height) were experienced in the morning, and lessened in the late afternoon to early evening. After the system passes, we plan to return to proposed Site VMVM-80A.

The scientists continued to analyze samples and data from Sites U1572 and U1573, and prepared site reports and science presentations.


Daily Science Report for 21 September 2021

Location: In transit on a heavy weather and seas avoidance course. Midnight position 67°6.10′N, 5°14.90′E

Science Update: Pipe tripping was completed by 0600 h and all RCB components were disassembled, inspected, and laid out. The rig floor was secured for transit and the thrusters and hydrophones were pulled up to start our sea passage. At 0730 h, we were underway at a 210° heading and reduced speed to avoid the heaviest seas and severe weather approaching Site U1573 in the Norwegian Sea. After the system passes, we plan to return to the area and continue operations at proposed Site VMVM-80A.

The scientists continued to analyze samples and data from Sites U1572 and U1573, and prepared site reports and science presentations.


Daily Science Report for 20 September 2021

Location: Hole U1573A (68°45.6240′N, 5°47.6880′E; water depth 3167.2 mbsl; proposed Site VMVM-09A)

Science Update: We continued to RCB core Hole U1573A until 1925 h when coring operations were ended due to approaching severe weather. The last core on deck was Core U1573A-19R, recovered from 440.9 mbsf. The rig floor crew began to raise the drill string and secure the coring tools. By the end of the day, the bit was raised to 2096 mbsl. The total amount of core recovered from Hole U1573A is 101 m (72%).

In the laboratories, we continued to measure and describe cores from Hole U1573A. Cores U1573A-12R to 18R primarily consist of aphyric basalt with interbedded dark greenish gray to very dark gray to black claystone with varying amounts of silt and sand. Slightly to moderately bioturbated, and finely (mm) to thickly (0.6–1 cm) laminated intervals are present. Palynological analyses confirmed a late early Eocene age for the sediments recovered between ~300 mbsf and the intrabasaltic sediments. We continued to analyze samples and data from Sites U1572 and U1573, and prepared site reports and science presentations.


Daily Science Report for 19 September 2021

Location: Hole U1573A (68°45.6240′N, 5°47.6880′E; water depth 3167.2 mbsl; proposed Site VMVM-09A)

Science Update: We continued to RCB core Hole U1573A. Cores U1573A-10R to 14R advanced the hole from 386.5 to 415.6 mbsf. The total amount of core recovered so far from Hole U1573A is 89.2 m (77%).

In the laboratories, we described Cores U1573A-7R to 11R. They consist of an alternating succession of greenish gray to dark gray, slightly to moderately bioturbated to finely laminated claystone with sand and claystone with silt. Pyrite is common throughout the sequence. The scientists continued to analyze samples and data from Sites U1572 and U1573, and prepared site reports and science presentations.

An abandon ship and fire drill was held at 1300 h followed by the expedition group photo.


Daily Science Report for 18 September 2021

Location: Hole U1573A (68°45.6240′N, 5°47.6880′E; water depth 3167.2 mbsl; proposed Site VMVM-09A)

Science Update: After advancing the hole without coring to 300 mbsf, we cut Cores U1573A-2R and 3R to 318.4 mbsf before we had to pause coring operations at 0745 h to secure the rig floor because of deteriorating weather and sea conditions. Coring operations resumed at 1200 h, once weather conditions had improved sufficiently that it was deemed safe for the drill floor crew to return to work. RCB coring then continued through the rest of the day, advancing the hole to 376.7 mbsf with Cores 4R to 9R by midnight. The total amount of core recovered from 300 to 376.7 mbsf was 70.81 m (92%).

In the laboratories, we described Cores U1573A-2R to 6R. They consist primarily of an alternating succession of dark greenish gray to dark gray, moderately to heavily bioturbated to finely laminated claystone. Biosiliceous content increases in the deeper part of the section. Gravel to large pebble size (8–65 mm) pyrite was observed in Cores U1573A-4R and 5R. The scientists continued to analyze data from Sites U1572 and U1573, and prepared site reports.


Daily Science Report for 17 September 2021

Location: Hole U1573A (68°45.6240′N, 5°47.6880′E; water depth 3167.2 mbsl; proposed Site VMVM-09A)

Science Update: We completed the 99 nmi transit to Site U1573 at 0130 h. After lowering the thrusters and switching the ship’s navigation system to automatic DP, the rig crew was cleared to begin operations. By 0400 h, the 4-stand RCB BHA was assembled and lowered to 172.1 mbrf. We continued deploying the drill string to the seafloor, filling the pipe with water every 20 stands. At 1140 h, with the end of the pipe at 3146 mbrf, we picked up the top drive, spaced out the bit, and spudded Hole U1573A. We spent the rest of the day drilling ahead with a center bit in place. By midnight, the drill bit had advanced to 233.6 mbsf. We plan to continue drilling ahead to 300 mbsf and then begin RCB coring to the target depth into basement before weather and sea conditions are anticipated to deteriorate in ~3 days.

In the laboratories, we continued to describe and measure cores from Hole U1572B. Cores U1572B-15H to 29F (130.3–209.6 mbsf) consist of a succession of biosiliceous ooze with ash-rich beds. A dark brown, organic-rich horizon with thin parallel laminations was documented throughout Core 19F. Cores 30X to 33X (209.6–224.3 mbsf) contain interbedded basaltic andesite, hyaloclastite, and volcanoclastic sediment.

The scientists continued to analyze data from Sites U1570, U1571, and U1572, and prepared site reports.


Daily Science Report for 16 September 2021

Location:

  • Hole U1572B (67°19.9178′N, 3°37.0570′E; water depth 1206.5 mbsl; proposed Site VMVM-07A)
  • Underway to Site U1573 (proposed site VMVM-09A)

Science Update: Today we completed coring in Hole U1572B. Cores U1572B-18F to 33X extended the hole to a final depth of 224.3 mbsf. Coring with the HLAPC ended when reaching APC refusal with Core U1572B-29F. We then deployed the XCB coring system using half-length advances to improve recovery of the sediment-to-basement transition. XCB coring was ended after Core U1572B-33X, when we determined that we were a few meters into basement. The total amount of core recovered from Hole U1572B is 218.3 m (97%). Following the recovery of the last core at 1045 h, we retrieved the drill string, disassembled and laid out all its components, and cleaned and secured the rig floor for transit. By 1645 h, we had raised and secured the hydrophones and thrusters and began our sea passage to Site U1573 (proposed Site VMVM-09A). By midnight, we had completed 87 nmi of the 99 nmi transit at a speed of 11.9 kt.

In the laboratories, we continued to describe and measure cores from Hole U1572B. Cores U1572B-5H to 14H (35.3–130.3 mbsf) consist of a succession of greenish gray to dark gray clay with varying amounts of sand to biosiliceous ooze and diatomite downhole. Ash-rich beds are common from Cores 11H to 14H. An interval of calcareous nannofossil ooze was documented in Core 10H. The micropaleontology team estimates a middle Miocene age for the base of Cores 12H and 13H, and a middle Eocene age for the base of Cores 18F and 19F, based on biosiliceous and organic microfossils.

The scientists continued to analyze data from Sites U1570, U1571, and U1572, and prepared site reports.


Daily Science Report for 15 September 2021

Location:

  • Hole U1572A (67°19.8477′N, 3°37.1620′E; water depth 1210.5 mbsl; proposed Site VMVM-07A)
  • Hole U1572B (67°19.9178′N, 3°37.0570′E; water depth 1206.5 mbsl; proposed Site VMVM-07A)

Science Update: After the logging equipment was stored and secured, we recovered the drill string, and inspected and laid out all the components while moving the ship 147 m west in DP mode to the location of Hole U1572B. At 0415 h, we began to assemble the outer APC/XCB core barrel and the BHA while deploying the drill string down to the seafloor, filling the pipe with seawater every 20 stands. At 0845 h, we picked up the top drive and spaced out the bit above the seafloor in preparation to spud Hole U1572B. We fired the mudline core, recovering 6.78 m of sediment, and spudded Hole U1572B at 1015 h. Based on core recovery, we determined the water depth to be 1206.5 mbsl. We continued coring with the APC system to 149.3 mbsf when 90,000 lbs of overpull were required to release Core U1572B-16H from the formation. We switched to the HLAPC and continued coring. Cores 17F to 23F advanced the hole to 182.1 mbsf by midnight. The total amount of core recovered today from Hole U1572B was 187.5 m (103%).

In the laboratories, we finished describing the last five cores from Hole U1572A and began measuring and describing cores from Hole U1572B. Cores U1572A-42R to 46R (301.3–330.5 mbsf) consist of aphyric basalt with varying vesicularity. Cores U1572B-1H to 4H (0–35.3 mbsf) consist of interbedded clay and sandy-rich clay. The micropaleontology team estimated a middle Eocene age for the base of Core U1572B-19F, based on biosiliceous and organic microfossils.

The scientists continued to analyze data from Sites U1570, U1571, and U1572, and prepared site reports.


Daily Science Report for 14 September 2021

Location: Hole U1572A (67°19.8477′N, 3°37.1620′E; water depth 1210.5 mbsl; proposed Site VMVM-07A)

Science Update: We completed RCB coring in Hole U1572A with Cores U1572A-42R to 46R, advancing the hole to a final depth of 330.5 mbsf. The total amount of core recovered from Hole U1572A was 139.53 m (42%).

Following the retrieval of the last core at 1240 h, we secured the coring tools and began preparations for wireline logging. We conducted a 50-barrel high viscosity mud sweep to clean the hole and then lowered the (RST) and released the bit at the bottom of the hole. We displaced the hole with 110 barrels of 10.5 ppg mud, raised the drill string to set the end of the pipe at 81 mbsf for logging, and further displaced the hole from the end of the pipe to the top of the hole with 20 barrels of 10.5 ppg mud. The triple combo tool string was rigged up by 1900 h and deployed, but was only able to reach 256 mbsf (74.5 m off bottom). We conducted an upward pass and could not complete a second pass as the hole had deteriorated. Logging activities were suspended, and the tool was recovered safely back onboard at 2330 h. We spent the rest of the day rigging down the logging equipment.

In the laboratories, we continued measuring and describing cores from Hole U1572A. Cores U1572A-28R to 41R mainly consist of basalt and interbasaltic sediment. The basalt is mainly hypocrystalline aphyric basalt, occasionally with trace copper, and rare sparsely plagioclase phyric basalt. The interbasaltic sediment is dark greenish gray to dusky red to black volcaniclastic sandstone or claystone likely from in situ breakdown of basalt.

The scientists continued to analyze data from Sites U1570, U1571, and U1572, and prepared site reports.


Daily Science Report for 13 September 2021

Location: Hole U1572A (67°19.8477′N, 3°37.1620′E; water depth 1210.5 mbsl; proposed Site VMVM-07A)

Science Update: We continued RCB coring in Hole U1572A from 242.2 to 296.5 mbsf (Cores U1572A-30R to 41R). Total core recovered for today was 44 m (75%).

In the laboratories, we continued measuring and describing cores from Hole U1572A. Cores 23R to 27R consist of a downhole succession of very dark greenish gray basaltic andesite to dark gray aphyric basalt with intervals of sparsely plagioclase phyric basalt and occasional interbedded intrabasaltic sediment. Palynological analyses confirmed the presence of abundant remains of the freshwater fern Azolla in Eocene sediment above the basalt. Interstitial water (IW) analysis showed very low alkalinity values in the porewater of intrabasaltic sediment layers.

The scientists continued to analyze samples and data from Sites U1570, U1571, and U1572, and prepared site reports.


Daily Science Report for 12 September 2021

Location: Hole U1572A (67°19.8477′N, 3°37.1620′E; water depth 1210.5 mbsl; proposed Site VMVM-07A)

Science Update: Rotary coring continued throughout the day with Cores U1572A-5R to 29R, deepening the hole from 38.5 mbsf to 242.2 mbsf. Basement was reached at 204 mbsf in Core 22R. Core recovery of the sedimentary succession was 46.44 m (22%). Core recovery throughout the basement section was 27.65 m (71%).

In the laboratories, we finished measuring and describing cores from Hole U1571B and began to measure and describe cores from Hole U1572A. Cores U1571B-15X to 21X consist of dark brown volcaniclastic claystone with varying sand content and parallel laminations. We observed hyaloclastite and aphyric basalt interbedded within the sediment.

Cores U1572A-1R to 11R consist of brown to gray to very dark gray clay with silt and some intervals of calcareous nannofossil ooze. Cores 12R to 13R consist of alternating ash-rich diatomite and diatom ooze. Cores 14R to 16R consist of alternating layers of radiolarian and diatom ooze and ash. Cores 17R to 21R consist of diatom-rich claystone and siltstone with ash. Core 22R contained sandstone and completely altered light gray andesite. Biostratigraphic and palynological analyses estimate an age of late early Eocene at the base of Core 21R.

The scientists continued to analyze samples and data from Sites U1570, U1571, and U1572, and prepared site reports.


Daily Science Report for 11 September 2021

Location:

  • Hole U1571B (67°18.4019′N, 3°44.2768′E; water depth 1205.3 mbsl; proposed Site VMVM-61A)
  • Hole U1572A (67°19.8477′N, 3°37.1620′E; water depth 1210.5 mbsl; proposed Site VMVM-07A)

Science Update: Today we completed coring operations at Site U1571 and began to RCB core at Site U1572.

At Site U1571, Cores U1571B-15X to 20X extended the hole from 120.3 mbsf to the final depth of 143.7 mbsf, with good recovery of the sediment-basement transition (68%). Total core recovered at Hole U1571B is 112.5 m (78%). At 1030 h, after recovery of the last core, we began pipe tripping operations, which continued during transit in DP mode to Site U1572 (proposed Site VMVM-07A). All APC/XCB BHA components were retrieved and stored, the rig’s traveling equipment was serviced, and a new RCB BHA was made up.

We arrived over the Site U1572 coordinates at 1600 h while deploying the drill string down to the seafloor. At 1930 h, with the end of the pipe at 1172.6 mbsl, we spaced out the bit and attempted to spud Hole U1572A based on a PDR depth of 1207.6 mbsl, but the core was retrieved empty. We added a single joint of pipe and dropped an RCB core barrel for a second attempt. This time we recovered 5 m of core, spudding Hole U1572A at 2145 h, and determining a water depth of 1210.5 mbsl. We continued RCB coring, retrieving Cores U1572A-2R to 4R (5 to 38.5 mbsf) with an overall recovery of 11 m (29%).

In the laboratories, we continued to measure and describe cores from Hole U1571B. Cores U1571B-4H to 9X consist of gray to greenish gray clay with increasing sand content with depth, Cores 10X to 12X mainly consist of greenish gray diatom ooze, and Cores 12X and 13X consist of an ash-rich clay overlying sand-rich claystone. Biostratigraphic markers estimate an age of 49 Ma for the base of this succession.

The scientists continued to analyze data from Sites U1570 and U1571 and prepared site reports.


Daily Science Report for 10 September 2021

Location:

  • Hole U1571A (67°18.4017′N, 3°44.2496′E; water depth 1205.8 mbsl; proposed Site VMVM-61A)
  • Hole U1571B (67°18.4019′N, 3°44.2768′E; water depth 1205.3 mbsl; proposed Site VMVM-61A)

Science Update: The day began while deploying the UBI logging tool to the bottom of Hole U1571A. The tool string reached 237.9 mbsf and we conducted two upward passes collecting measurements through the open hole. The UBI was brought back to the surface at 0345 h and rigged down. After all logging equipment was stored and secured, we recovered the drill string, disassembled it, and inspected and laid out all the components by 0745 h. We made up the outer APC/XCB core barrel and the BHA and deployed the drill string back to the seafloor to begin Hole U15671B. At 1215 h, we picked up the top drive and the drilling knobbies, spaced out the bit above the seafloor, and shot the mudline core, recovering 5 m. Based on the core recovery, we determined the water depth to be 1205.3 mbsl. We continued coring to APC refusal, which was reached at 57.2 mbsf (Core U1571B-7H) at 1845 h. Then we switched to the XCB coring system and cored to 120.3 mbsf, recovering Core 14X by midnight. Total core recovered today from Hole U1571B was 37.9 m (60%).

In the laboratories, we finished measuring and describing cores from Hole U1571A and began to process cores from Hole U1571B. Cores U1571A-35R to 39R consist of aphyric basalt with sparsely plagioclase phyric basalt. Cores U1571B-1H-3H consist of yellowish brown to olive green clay with varying amounts of silt and sand.

The scientists continued to analyze data from Sites U1570 and U1571 and prepared site reports.


Daily Science Report for 9 September 2021

Location: Hole U1571A (67°18.4017′N, 3°44.2496′E; water depth 1205.8 mbsl; proposed Site VMVM-61A)

Science Update: We completed coring operations in Hole U1571A after recovering Cores U1571A-37R to 39R from 228.1 mbsf to a final depth of 247.6 mbsf. Total core recovery for Hole U1571A is 116.55 m (47%).

Following the retrieval of the last core at 0525 h, we cleaned the hole by pumping 50 barrels of high viscosity mud and then lowered the (RST) and released the bit at the bottom of the hole. We displaced the hole with 75 barrels of 10.5 ppg mud, raised the drill string, and set the end of the pipe at 87 mbsf in preparation for downhole logging. At 1000 h, we rigged up the triple combo tool string and lowered it to 246.9 mbsf. We made two passes through the open hole, recovered the logging tool, and rigged it down by 1400 h. We deployed the FMS-sonic tool and conducted two passes from 246.9 mbsf upwards. After retrieving and rigging down the FMS-sonic tool at 1745 h, we lowered the drill pipe to the bottom of the hole, installed the circulation head, and circulated the hole with seawater in preparation for the deployment of the UBI tool. We raised the end of the pipe to 104.9 mbsf and, rigged up the UBI tool, and by midnight we were lowering the tool to the bottom of the hole.

In the laboratories, we continued to measure and describe cores from Hole U1571A. Cores U1571A-26R to 34R consist of aphyric basalt with sparsely plagioclase phyric basalt and few intervals of interbedded sediments.

The scientists continued to analyze data from Sites U1570 and U1571 and prepared site reports.


Daily Science Report for 8 September 2021

Location: Hole U1571A (67°18.4017′N, 3°44.2496′E; water depth 1205.8 mbsl; proposed Site VMVM-61A)

Science Update: Today we continued RCB coring with half-length advances in Hole U1571A from Cores 24R at 164.9 mbsf to 36R at 228.1 mbsf. The total core recovered over this interval was 53.2 m (84%).

Cores U1571A-19R to 26R consist of sparsely to highly vesicular aphyric basalt. Interbasaltic volcanoclastic sediments are common.

The scientists continued to analyze data from Sites U1570 and U1571 and prepared site reports.


Daily Science Report for 7 September 2021

Location: Hole U1571A (67°18.4017′N, 3°44.2496′E; water depth 1205.8 mbsl; proposed Site VMVM-61A)

Science Update: Today we continued RCB coring Hole U1571A from Cores 14R at 121.1 mbsf to 23R at 164.9 mbsf. The total core recovered over this interval was 17.1 m (39%).

Cores U1571A-4R to 8R mainly consist of gray to very dark gray clay with silt. Cores U1571A-9R to 12R consist of dark brown to dark greenish gray clay with silt-rich and sand-rich intervals, and moderate bioturbation. Cores 13R to 18R mainly contain yellowish brown to reddish brown volcaniclastic sediments with occasional nodules alternating with aphyric basalt. The scientists continued to analyze data from Sites U1570 and U1571 and prepared site reports.


Daily Science Report for 6 September 2021

Location: Hole U1571A (67°18.4017′N, 3°44.2496′E; water depth 1205.8 mbsl; proposed Site VMVM-61A)

Science Update: We completed the 97 nmi transit to Site U1571 (proposed Site VMVM-61A) in 9.1 h, ending the sea passage at 0918 h. The vessel was switched to DP mode and the drill floor was cleared for operations at 0952 h. We made up and deployed the RCB BHA with a new bit and bit release system to 172 mbrf and then continued to lower the drill pipe to the seafloor while filling it with water every 20 stands. Beginning at 1330 h, we picked up the top drive and the drilling knobbies, spaced out the bit to just above the seafloor, and spudded Hole U1571A at 1500 h at 1205.8 mbsl. Rotary coring continued from the seafloor to 121.1 mbsf by midnight (Cores U1571A-1R to 13R). The total core recovered was 35 m (29%).

Cores U1571A-1R to 3R were measured and described. They contain grayish brown clay with silt and foraminifers. Biostratigraphic markers suggest a middle Miocene age for Cores 9R and 10R. The scientists continued to analyze data from Sites U1570 and U1571 and prepared site reports.


Daily Science Report for 5 September 2021

Location: Hole U1570D (65°49.8708′N, 1°59.1743′E; water depth 2207.7 mbsl; proposed Site VMVM-56A)

Science Update: Cores U1570D-24R to 28R extended the hole from 149.2 mbsf to the final depth of 200 mbsf at 0230 h. The total amount of core recovered at Hole U1570D was 50.5 m (25%). Following the retrieval of the last core, we conducted a 50-barrel high viscosity mud sweep to clean the hole, then ran the RST in on the coring line and released the RCB coring bit in the bottom of the hole. We ran the RST again to reposition the bit shifting sleeve back to the circulating position and displaced the hole with 65 barrels of 10.5 ppg mud. We set back the top drive and raised the end of the pipe to 76 mbsf in preparation for wireline logging. We rigged up the triple combo tool string and lowered it to 199.8 mbsf. We conducted two upward passes of the open hole, collecting magnetic susceptibility, resistivity, density (with caliper), neutron porosity, temperature, and natural gamma radiation data. The triple combo tool string was recovered by 1220 h. We then rigged up and deployed the FMS-sonic tool and conducted two passes from 199.3 mbsf upwards. At 1800 h, after retrieving the FMS-sonic tool and rigging down all the logging equipment, the rig floor was cleared for pipe tripping operations. The drill pipe was picked up and stacked, the BHA drill collar stands were set back, and all core barrel components were broken down, inspected, and laid out. The rig floor was secured for transit at 2345 h. The thrusters were raised in preparation for departure and transit to the next site.

In the Core Laboratory, we measured and described the remaining cores from Hole U1570D. Cores U1570D-14R to 16R mainly consist of garnet-bearing dacite, with cordierite, pyrite, and graphite. Transitions between sediment and lava flows are present in part of this interval. Cores U1570D-17R to 19R mainly consist of very dark gray siltstone with clay with no bioturbation. Dewatering structures and pyrite are common. Cores U1570D-20R to 28R contain very dark gray to dark greenish gray siltstone with moderate bioturbation. Occasional carbonate-rich layers are present. Volcaniclastic (tuffaceous) sediments are common in Core U1570D-20R. Palynological proxies provide an estimated age of late Paleocene for the base of the cored section.

The scientists continued to collect and analyze data from Site U1570, and prepared site reports.


Daily Science Report for 4 September 2021

Location:

  • Hole U1570C (65°49.8485′N, 1°58.7077′E; water depth 2225.1 mbsl; proposed Site VMVM-56A)
  • Hole U1570D (65°49.8708′N, 1°59.1743′E; water depth 2207.7 mbsl; proposed Site VMVM-56A)

Science Update: After raising the drill bit to 2169 mbsl, we moved the vessel along the approved ribbon for Site U1570 to the position of Hole U1570D. We began rotary coring at 0250 h and Cores U1570D-1R to 26R penetrated from the seafloor to 179 mbsf by midnight. Total core recovered for this interval is 46.25 m (26%). Cores 10R (80.9 mbsf) through 23R (149.2 mbsf) were taken with half-length advances to improve recovery across this interval, which increased to 48%.

In the laboratories, we measured and described the remaining cores from Hole U1570C and began to process the cores from Hole U1570D.

Cores U1570C-14R to 16R sampled very dark greenish gray, moderately bioturbated claystone with silt. Cores 17R to 23R sampled very dark gray siltstone with clay with some sand-rich intervals with moderate bioturbation. Pyrite is observed. Some intervals show thin parallel lamination.

Cores U1570D-1R to 6R consist of brown and grayish brown clay with silt and foraminifers. Cores 6R-2 to 13R consist of dark gray claystone with various amounts of ash and some fining upwards structures with slight bioturbation and parallel lamination.

The scientists continued to collect and analyze data from Site U1570, and prepared site reports.


Daily Science Report for 3 September 2021

Location:

  • Hole U1570B (65°49.6788′N, 1°57.3605′E; water depth 2270.9 mbsl; proposed Site VMVM-56A)
  • Hole U1570C (65°49.8485′N, 1°58.7077′E; water depth 2225.1 mbsl; proposed Site VMVM-56A)

Science Update: After pulling out of Hole U1570B, we raised the end of the pipe to 2197 mbsl and moved along the approved ribbon for Site U1570 to Hole U1570C. At 0405 h, we began coring Hole U1570C at a PDR depth of 2208.1 mbsl. Cores U1570C-1R to 23R deepened the hole to a final depth of 200 mbsf by 2315 h. The end of the day was spent raising the end of the pipe out of the hole with the plan to core another hole at this site. Total core recovered at Hole U1570C is 49.59 m (25%).

In the laboratories, we measured and described the remaining cores from Hole U1570B and began to process the cores from Hole U1570C.

Cores U1570B-21R to 23R-3 consist of alternating layers of gray to dark gray siltstone, ash, and limestone. Cores 24R and 25R are predominantly clay-rich siltstone.

Cores U1570C-1R to 5R consist of grayish brown to dark olive gray clay with silt and foraminifers. Occasional sand-rich layers and nodules are observed. Sandstone and claystone clasts were found at the base of Core 5R. Cores 6R through 13R consist of very dark greenish gray bioturbated claystone with silt.

The scientists continued to collect and analyze data from Site U1570, and prepared site reports.


Daily Science Report for 2 September 2021

Location: Hole U1570B (65°49.6788′N, 1°57.3605′E; water depth 2270.9 mbsl; proposed Site VMVM-56A)

Science Update: Today we completed coring operations at Hole U1570B. Cores U1570B-7R to 25R advanced the hole from 46.6 mbsf to a final depth of 163.6 mbsf at 2345 h. Total core recovered at Hole U1570B is 71.42 m (44%). We secured the coring tools and prepared to pull out of the hole. Our plan is to move the ship to a new position along the approved ribbon for Site U1570 and core a third hole at this site.

In the laboratories, we measured and described the remaining cores from Hole U1570A and began to process the cores from Hole U1570B. Cores U1570A-31R to 36R mainly consist of dark gray to very dark grayish brown siltstone with clay, sometimes with parallel lamination. Dewatering structures are present through most of this interval and pyrite is also common.

Cores U1570B-1R to 3R mainly consist of pale yellow to brown to very dark gray clay-rich silt or sand, with foraminifers present in Core U1570B-1R. Cores U1570B-4R to 10R mainly consist of dark gray claystone, sometimes with parallel lamination. Cores 11R to 13R consist of sandstone dominated by volcanic ash, gravel, and conglomerate. Cores 14R to 20R consist of greenish black siltstone with clay with occasional gray volcanic ash beds and occasional limestone or carbonate-rich beds. Parallel lamination and pyrite are common.

In the afternoon, we held the science summary meeting for Sites U1567 and U1568 with the participation of the onshore members of the science party. The scientists continued to collect and analyze data from Site U1570, and prepared site reports.


Daily Science Report for 1 September 2021

Location:

  • Hole U1570A (65°49.8901′N, 1°59.6225′E; water depth 2196.1 mbsl; proposed Site VMVM-56A)
  • Hole U1570B (65°49.6788′N, 1°57.3605′E; water depth 2270.9 mbsl; proposed Site VMVM-56A)

Science Update: Today we completed rotary coring in Hole U1570A, from 142.1 mbsf (Core U1570A-25R), to a final depth of 200 mbsf (Core 36R). The total recovery for the hole was 98.59 m (49%). After coring was completed at 1045 h, we raised the drill bit out of the hole to a depth of 2153.7 mbsl, at 1230 h. We moved in DP mode to Hole U1570B, along the approved ribbon line for Site U1570. We picked up the top drive and conducted routine rig servicing. After positioning the ship over the new hole coordinates, we spaced out the bit above the seafloor, lowered an RCB core barrel, and started rotary coring in Hole U1570B, at 1610 h, at a PDR depth of 2270.9 mbsl. We recovered Cores U1570B-1R to 6R (46.6 mbsf) with a recovery of 18 m (38%).

Today we measured and described Cores U1570A-12R to 30R. They consist of gray to very dark gray claystone with silt and sand, often laminated, and with occasional microfault structures. Black ash beds are common throughout. Glendonite is observed at three stratigraphic levels, and trace mollusks are present in Cores U1570A-29R and 30R.

The scientists continued to collect and analyze data from Sites U1569 and U1570, and prepared site reports.