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IODP Expedition 393

South Atlantic Transect 2


Daily Science Report for 28 June 2022

Location:

  • Hole U1558F (30°53.7923′S, 24°50.4757′W, water depth 4337 mbsl)
  • Hole U1558D (30°53.7814′S, 24°50.4822′W, water depth 4334 mbsl)

Science Update: We completed disassembly of the BHA at 0035 h, ending operations at Hole U1558F. We then made up the RCB BHA and lowered it down to Hole U1558D, where a reentry system had been installed during Expedition 390C in November 2020. Guided by the subsea camera video feed, the ship maneuvered over the hole and the bit reentered Hole U1558D at 1505 h. We lowered the bit to the depth of the existing hole, 150 mbsf, and started coring at 1845 h. Cores U1558D-2R to 3R penetrated from 150 to 166.5 mbsf and recovered 3.27 m (20%). These cores contain sediment. The depth of the basement contact is expected to be between 159 and 176 mbsf, the depths of the contact at Holes U1558A and U1558F, respectively.

Cores U1558F-16F to 24X were split and described. Cores 16F to 20X are nannofossil ooze, Cores 21X to 22X are nannofossil chalk with clay in some layers, and Cores 23X to 24X are nannofossil chalk with clay. The lowermost 10 cm of Core 24X is basalt. Cores 16F to 24X are earliest Oligocene to middle Eocene in age.


Daily Science Report for 27 June 2022

Location: Location: Hole U1558F (30°53.7923′S, 24°50.4757′W, water depth 4337 mbsl)

Science Update: Cores U1558F-16F to 24X penetrated from 110.4 to 177.2 mbsf and recovered 60.0 m (90%). After a drillover on Core 19F we switched to XCB drilling for the rest of the hole. We contacted basement in Core 24X at 176 mbsf, drilled 1.2 m further in an effort to recover the uppermost basement rocks, and then ended the hole. Basement depth in Hole U1558F is 17 m deeper than the basement depth in Hole U1558A, indicating that there is steep basement topography at this site. At 1415 h we started to pull the BHA up to the ship and by midnight we had begun disassembling the BHA. Cores U1558F-6H to 15F were split and described. Core 6H is nannofossil ooze with clay and Cores 7H to 11F alternate between nannofossil ooze and nannofossil ooze with clay. Cores 12F to 15F are nannofossil ooze. Cores 6H to 15F are Oligocene in age.


Daily Science Report for 26 June 2022

Location:

  • Hole U1558E (30°53.7922′S, 24°50.4822′W)
  • Hole U1558F (30°53.7923′S, 24°50.4757′W, water depth 4337 mbsl)

Science Update: We lowered the bit to 4319 mbsl but bad weather delayed the start of Hole U1558E, and we waited until ship heave was starting to subside. At 0440 h we started Hole U1558E, but the core barrel was full and did not recover a mudline so we offset 10 m to the east and at 0610 h started Hole U1558F. Cores U1558F-1H to 15F penetrated from 0 to 110.4 mbsf and recovered 104.5 m (95%). Whole-round samples were taken for microbiological studies and oxygen content was measured by needle probe soon after the cores were recovered. Cores U1558F-1H to 5H are clayey nannofossil ooze. Core 1H contains a hiatus or condensed interval and Cores 2H to 5H are early Miocene to late Oligocene in age.


Daily Science Report for 25 June 2022

Location:

  • Underway to Site U1558 (proposed Site SATL-43A)
  • Site U1558 (30°53.77′S, 24°50.49′W, water depth 4337 mbsl)

Science Update: The ship completed the final 114 nmi of the 508 nmi voyage to Site U1558 (proposed Site SATL-43A). In November 2020, Expedition 390C cored Hole U1558A to recover sediment down to the basement interface at 159 mbsf and installed a reentry system in Hole U1558D. Holes U1558B and U1558C were the locations of unsuccessful attempts to install the reentry system. At 1130 h we arrived on site and lowered the thrusters. In preparation for Hole U1558E, we made up the advanced piston corer/extended core barrell (APC/XCB) BHA and lowered it down to 4310 mbsl. At 2300 h we picked up the top drive, and pumped down a pipecleaning device to clean the inside of the pipe. The science party worked on Site U1559 reports.


Daily Science Report for 24 June 2022

Location: Underway to Site U1558 (proposed Site SATL-43A)

Science Update: The ship completed 269 nmi for a total of 394 nmi of the 508 nmi voyage to Site U1558. COVID-19 mitigation protocols were lifted at 0700 h. The science party met in the conference room for presentations to review operations at Hole U1559B and plan for the next site, Site U1558. We completed sampling of the Hole U1559B cores for shipboard measurements.


Daily Science Report for 23 June 2022

Location:

  • Hole U1559B (30°15.6336′S, 15°2.0941′W, water depth 3055 mbsl)
  • Underway to Site U1558 (proposed Site SATL-43A)

Science Update: Core U1559B-13R penetrated from 104.1 to 107.9 mbsf and recovered 0.34 m (9%). Core 13R contains sparsely plagioclase phyric microcrystalline basalt with rare olivine and clinopyroxene phenocrysts. One core piece has a glassy rim. At 0300 h we stopped coring because of the slow penetration rate and because the bit was wearing down. We pulled the bit out of the hole and raised it to the ship. The rig floor crew disassembled the BHA and secured the rig floor for transit, ending operations at Hole U1559B at 1235 h. We raised the thrusters and were underway to Site U1558 at 1242 h. By midnight, the ship had completed 125 nmi of the 508 nmi voyage. COVID-19 mitigation protocols continue to be followed.


Daily Science Report for 22 June 2022

Location: Hole U1559B (30°15.6336′S, 15°2.0941′W, water depth 3055 mbsl)

Science Update: Cores U1559B-9R to 12R penetrated from 92.9 to 104.1 mbsf and recovered 5.13 m (46%). Cores U1559B-9R to 12R contain relatively fresh microcrystalline to fine grained sparsely plagioclase phyric basalt, with rare fresh olivine. Cores 11R and 12R also contain rare clinopyroxene phenocrysts. COVID-19 mitigation protocols continue to be followed.


Daily Science Report for 21 June 2022

Location: Hole U1559B (30°15.6336′S, 15°2.0941′W, water depth 3055 mbsl)

Science Update: Cores U1559B-5R to 8R penetrated from 73.5 to 92.9 mbsf and recovered 5.67 m (29%). The cores are half-length and the average rate of penetration is ~1.1 m/h. Cores U1559B-5R to 8R contain relatively fresh microcrystalline to fine grained sparsely plagioclase phyric basalt, with rare fresh olivine phenocrysts, and rare clay and carbonate veins. All shipboard personnel took their second-to-last COVID-19 antigen test of the mitigation period, and COVID-19 mitigation protocols continue to be followed.


Daily Science Report for 20 June 2022

Location: Hole U1559B (30°15.6336′S, 15°2.0941′W, water depth 3055 mbsl)

Science Update: At the start of the day we were preparing to reenter Hole U1559B. A “pig” was pumped down the drill pipe to clean out any debris from the inside, and the bit depth was set for reentry. We reentered the hole at 0143 h and washed down to 58.9 meters below seafloor (mbsf), the depth the hole had reached when casing was installed in it during Expedition 390C. The subsea camera was pulled back up to the ship. At 0430 h we began coring with the rotary core barrel (RCB) system. Cores U1559B-2R to 4R advanced from 58.9 to 73.5 mbsf and recovered 1.68 m (12%). The cores are half-length and Core 2R was empty. Cores 3R and 4R contain slightly altered basalt pieces, some with euhedral plagioclase phenocrysts. COVID-19 mitigation protocols continue to be followed.


Daily Science Report for 19 June 2022

Location:

  • Underway to Site U1559 (proposed Site SATL-13A)
  • Hole U1559B (30°15.6336′S, 15°2.0941′W, water depth 3055 mbsl)

Science Update: The ship transited 135 nmi and arrived at Site U1559 at 1220 h, completing its 1713 nmi voyage from Cape Town, South Africa. We lowered the thrusters and switched from cruise mode into DP mode. Operations started on the rig floor with assembly of the bottom-hole assembly (BHA). At 1630 h the BHA was complete and we started adding drill pipe to lower the bit down through the water column. At 2130 h the bit reached 2482 meters below sea level (mbsl) and we deployed the subsea camera in preparation for reentry into Hole U1559B. By midnight we had lowered the bit to 3031 mbsl and picked up the top drive. COVID-19 mitigation protocols continue to be followed.


Daily Science Report for 18 June 2022

Location: Underway to Site U1559 (proposed Site SATL-13A)

Science Update: The ship completed 260 nmi for a total of 1578 nmi of the 1706 nmi voyage to Site U1559. The science party met for presentations about the coring tools and they continued to prepare the laboratories for new core. COVID-19 mitigation protocols are being followed. We expect to arrive on site around midday on 19 June.


Daily Science Report for 17 June 2022

Location: Underway to Site U1559 (proposed Site SATL-13A)

Science Update: The ship completed 175 nmi for a total of 1318 nmi of the 1706 nmi voyage to Site U1559. We completed the description of cores from Hole U1560A, collected during Expedition 395E. Cores U1560A-7H to 11X are nannofossil ooze with clay, and Cores 12X to 14X are nannofossil ooze with clay and foraminifers. In preparation for coring, the science party laboratory groups finalized and submitted their methods sections. COVID-19 mitigation protocols are being followed. We expect to arrive on site on the afternoon of 19 June.


Daily Science Report for 16 June 2022

Location: Underway to Site U1559 (proposed Site SATL-13A)

Science Update: The ship completed 167 nmi for a total of 1143 nmi of the 1706 nmi voyage to Site U1559. The clocks were put back one hour, which was the second time change of the transit. The ship is now on the UTC + 0 h time zone and will remain there until the transit back to Cape Town after coring operations are complete. We described cores from Hole U1560A, collected during Expedition 395E. Cores U1560A-1H to 5H are nannofossil ooze with clay and foraminifers, and Core 6H is nannofossil ooze with clay. COVID-19 mitigation protocols are being followed. Despite being slowed by high winds, we still expect to arrive on site on 19 June.


Daily Science Report for 15 June 2022

Location: Underway to Site U1559 (proposed Site SATL-13A)

Science Update: The ship completed 193 nmi for a total of 976 nmi of the 1706 nmi voyage to Site U1559. Ship speed slowed to 8 kt today because of high winds and rough seas. We completed the description of cores from Hole U1558A, collected during Expedition 390C. Cores U1558A-6H to 13X are nannofossil ooze and Cores U1558A-14X to 18X are nannofossil chalk with clay. Micropaleontological samples from Hole U1558A are being analyzed for foraminifer and nannofossil biostratigraphy. We took X-ray images of Cores U1558A-1H to 11H to gauge whether to run the X-ray instrument on new cores later in the expedition. COVID-19 mitigation protocols are being followed.


Daily Science Report for 14 June 2022

Location: Underway to Site U1559 (proposed Site SATL-13A)

Science Update: The ship completed 258 nmi for a total of 783 nmi of the 1706 nmi voyage to Site U1559. We started description of cores from Holes U1558A and U1560A, which had been collected on Expeditions 390C and 395E in preparation for this expedition. Cores U1558A-1H to 6H are nannofossil ooze with varying concentrations of foraminifera and clay. Core U1558A-19X is moderately plagioclase-olivine phyric basalt, with slightly to moderately altered glass at chilled margins, baked pelagic ooze, and complex alteration haloes around carbonate and zeolite veins. Cores U1560A-15X and 16X, each less than 30 cm long, are sparsely plagioclase phyric basalt. Scientists continued to familiarize themselves with the procedures and instruments in their laboratories. COVID-19 mitigation protocols are being followed.


Daily Science Report for 13 June 2022

Location: Underway to Site U1559 (proposed Site SATL-13A)

Science Update: The ship completed 211 nmi for a total of 525 nmi of the 1706 nmi voyage to Site U1559. Five whole-round uppermost basement sections from Holes U1558A and U1560A were split and we started to make visual core descriptions (VCD). Core sampling training is being given for each laboratory group. COVID mitigation protocols are being followed. As part of this, all personnel are taking daily COVID-19 antigen tests during the first week of the 14-day COVID mitigation period. The ship is expected to arrive at Site U1559 on 19 June.


Daily Science Report for 12 June 2022

Location: Underway to Site U1559 (proposed Site SATL-13A)

Science Update: The ship completed 218 nmi for a total of 314 nmi of the 1706 nmi voyage to Site U1559. Five whole-round uppermost basement sections from Holes U1558A and U1560A, cored on Expeditions 390C and 395E, were recurated. The images of the 360° exterior of the sections were taken on the Deutsche Montan Technologie (DMT) scanner. The scientists took hazard communication and laboratory safety training and continued to prepare for coring.


Daily Science Report for 11 June 2022

Location:

  • Repair Quay 3, Cape Town, South Africa
  • Underway to Site U1559 (proposed Site SATL-13A)

Science Update: The final three scientists boarded the ship at 0630 h. The pilot boarded at 0910 h and the ship departed Repair Quay 3, with the last line released at 0949 h. Contractors came onboard during departure to conduct testing of the 50 kVA uninterruptible power supply (UPS) system under different levels of electrical load, which included dynamic positioning (DP) and running drilling equipment and mud pumps. This testing took place at a location outside of the harbor, and by 1443 h testing was complete and the contractors left by launch boat. We started the sea voyage at 1455 h. By midnight the ship had completed 96 nmi of the 1706 nmi voyage to Site U1559.

All shipboard personnel took a COVID-19 antigen test today, day 1 of the 14-day mitigation period. All scientists continued to familiarize themselves with their laboratories and instruments, and work started on imaging the outside of the two whole-round core sections from Hole U1558A and three from Hole U1560A. These sections had been cored on Expeditions 390C and 395E and contain the uppermost basaltic rocks at these sites.


Daily Science Report for 10 June 2022

Location: Repair Quay 3, Cape Town, South Africa

Science Update: Port call activities continued. A group of six JRSO staff and scientists boarded the ship. All shipboard personnel took a final PCR test for COVID-19 before departure, after which we will use antigen testing for the duration of the 14-day COVID-19 mitigation period. Scientists on the night shift took a safety and orientation tour of the ship. The captain gave ship safety and orientation presentations to the day shift and night shift scientists. All scientists continued to familiarize themselves with their laboratories. Some final items of freight were loaded. The ship is scheduled to depart on 11 June.


Daily Science Report for 9 June 2022

Location: Repair Quay 3, Cape Town, South Africa

Science Update: The majority of the Expedition 393 ship’s crew, JRSO staff, and science party cleared immigration, boarded the vessel, and moved into their cabins. All oncoming participants went onto shift straight away, as part of the COVID-19 mitigation protocols. Scientists who were on shift in the afternoon took a safety and orientation tour of the vessel and began familiarizing themselves with the laboratories and connecting to the ship’s computer network. Other port call activities included unpacking and distribution of oncoming freight. The vessel is scheduled to depart on 11 June.


Daily Science Report for 8 June 2022

Location: Repair Quay 3, Cape Town, South Africa

Science Update: Representatives of the National Science Foundation (NSF) toured and inspected the ship. The oncoming IODP freight was loaded and all onboard personnel took antigen tests for their disembarkation on 9 June.

The Expedition 393 scientists, JRSO staff, and ship’s crew continued to quarantine at a hotel in Cape Town and took PCR tests following the JRSO COVID-19 mitigation protocols. All scientists who were due to board the ship on 9 June were cleared after receiving test results.

The scientists met virtually for presentations about the science results of Expedition 390, South Atlantic Transect 1, shipboard computing and imaging resources, and preboarding orientation. The ship is expected to depart Cape Town on 11 June.


Daily Science Report for 7 June 2022

Location: Repair Quay 3, Cape Town, South Africa

Science Update: IODP Expedition 393, South Atlantic Transect 2, officially began in the port of Cape Town, South Africa, at 0800 h. Port call activities included bunkering 530 mt of marine gas oil. Frozen and refrigerated samples and cores from Expedition 390 were offloaded. All onboard personnel were tested for COVID-19.

All oncoming Expedition 393 personnel, including JRSO staff and the science party, continued to quarantine in a hotel in Cape Town as part of preboarding COVID-19 mitigation protocols. The seven-day hotel quarantine period, which includes two COVID-19 tests, will end on 9 June for most participants. On 9 June the majority of the JRSO staff and science party plan to board the JOIDES Resolution. Five members of the JRSO staff and five scientists whose flights were delayed and arrived one or two days late will remain in the hotel for additional quarantine. During the hotel quarantine period, the Expedition 393 scientists began expedition preparation through a series of virtual meetings. These meetings included an introduction to the expedition, IODP curation and publications services, and presentation of individual research and shipboard outreach plans. Laboratory teams began meeting to discuss methods and shipboard sampling strategies.