IODP Expedition 392

Agulhas Plateau Cretaceous Climate

Daily Science Report for 28 February 2022

Location: Hole U1580A (40°47.1535′S, 26°36.4137′E; water depth 2560.3 mbsl; proposed Site AP-09B)

Science Update: Cores U1580A-25R to 36R advanced from 232.8 to 349.2 mbsf and recovered 82.8 m (71%). Sepiolite mud sweeps were pumped on Cores 29R and 34R.

Core U1580A-22R is composed primarily of white to grayish brown nannofossil chalk with varying clay content and low to intense bioturbation. Cores 23R to 30R are composed primarily of light greenish gray to greenish gray to light gray calcareous chalk with varying clay content. Cores 29R and 30R also contain intervals of dark grayish brown and grayish brown claystone. In Core 31R there is a transition from calcareous chalk to dark greenish gray to greenish black zeolitic sandstone with glauconite, which continues through Core 32R. Cores 22R to 32R span from the early Paleocene to Late Cretaceous in age.

Daily Science Report for 27 February 2022

Location: Hole U1580A (40°47.1535′S, 026°36.4137′E; water depth 2560.3 mbsl; proposed Site AP-09B)

Science Update: Cores U1580A-13R to 24R advanced from 116.4 to 232.8 mbsf and recovered 58.9 m (50%). Sepiolite mud sweeps were pumped on Cores 16R and 23R.

Cores U1580A-9R to 21R consist primarily of light greenish gray nannofossil ooze. Bioturbation is low to moderate. There are cm-scale pieces of chert in several cores. Cores 9R to 21R span from the late to early Paleocene in age.

Daily Science Report for 26 February 2022

Location: Location: Hole U1580A (40°47.1535′S, 026°36.4137′E; water depth 2560.3 mbsl; proposed Site AP-09B)

Science Update: Cores U1580A-3R to 12R advanced from 19.4 to 116.4 mbsf and recovered 59.4 m (61%).

Core U1580A-1R consists primarily of light gray foraminiferal ooze and transitions to pale yellow and white nannofossil ooze in Section U1580A-1R-3 which continues through Core 2R. The upper 1–2 sections of Cores 1R and 2R are heavily disturbed by drilling (soupy). Cores 3R to 8R consist primarily of light greenish gray nannofossil chalk with varying clay content. Cores 1R to 8R span from the early Eocene to late Paleocene in age.

Daily Science Report for 25 February 2022

Location:

Hole U1579D (39°57.0725′S, 026°14.1793′E; water depth 2492.9 mbsl; proposed Site AP-10A)
Underway to proposed Site AP-09B (Site U1580)
Hole U1580A (40°47.1535′S, 026°36.4137′E; water depth 2560.3 mbsl; proposed Site AP-09B)

Science Update: The pipe was tripped out of Hole U1579D, clearing the seafloor at 0110 h. We continued tripping pipe back to the rig floor and Hole U1579D ended at 0735 h. The rig floor was secured for transit, the thrusters were raised, and at 0740 h we began our sea passage. After completing the 53 nmi voyage we arrived at Site U1580 at 1306 h. The thrusters were lowered and the vessel switched to DP mode at 1326 h. The BHA was assembled and the pipe was tripped to the seafloor, tagging at 2560.3 mbsl. Hole U1580A was spudded at 2015 h. Cores U1580A-1R to 2R advanced from 0 to 19.4 mbsf and recovered 13.9 m (76%).

The science party received a presentation from the Co-Chief Scientists on the scientific objectives of proposed Site AP-09B (Site U1580) and prepared reports for Site U1579. The lowermost two sections of Core U1579D-65R are composed primarily of moderately altered basalt with vesicles.

Daily Science Report for 24 February 2022

Location: Hole U1579D (39°57.0725′S, 026°14.1793′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: Core U1579D-65R advanced from 722.4 to 727.2 mbsf and recovered 4.9 m (101%). The bit was released in the bottom of the hole at 0310 h and the hole was displaced with heavy mud. The pipe was tripped back to 70.7 mbsf and the Schlumberger Quad Combo tool was prepared. The hole was logged to 727.7 mbsf, with some high-resolution passes. We began pulling up the logging tools at 2040 h and the Quad Combo was back at the rig floor by the end of the day.

Core U1579D-61R to the middle of Section 64R-3 is plagioclase-clinopyroxene phyric basalt that ranges from highly altered to well preserved downhole. The grain size also increases downhole. In the middle of Section 64R-3 to the middle of Section 65R-3 the composition is primarily light greenish gray to grayish green lithic sandstone. The lower portion of Section 65R-3 is composed primarily of aphyric, moderately vesicular basalt. At the boundary between sediment and basalt in Section 65R-3 the contact is recovered, consisting of baked sediment and highly altered basalt.

Daily Science Report for 23 February 2022

Location: Hole U1579D (39°57.0725′S, 26°14.1793′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: Cores U1579D-59R to 64R advanced from 678.7 to 722.4 mbsf and recovered 40.3 m (92%).

Cores U1579D-55R through 59R are composed primarily of greenish gray to light greenish gray to pale green glauconitic sandstone, with some intervals of siltstone and claystone. Bioturbation ranges from absent to intense. Cores 55R through 59R are Late Cretaceous in age. Core 60R is composed primarily of grayish green glauconitic sandstone; however, in Section 60R-6 the lithology transitions to layers of gray silty claystone and light gray lithic sandstone. The bottom of Section 60R-7 and all of Section 60R-CC are composed of highly altered basalt. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 22 February 2022

Location: Hole U1579D (39°57.0725′S, 026°14.1793′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: Cores U1579D-52R to 58R advanced from 610.8 to 678.7 mbsf and recovered 58.2 m (86%).

In Hole U1579D, Core 50R through Section 52R-2 is composed primarily of light greenish gray to greenish gray calcareous chalk. There are also cm-scale layers of gray to reddish brown silicified limestone. Section 52R-3 through Core 53R is composed primarily of light and dark reddish brown and pale red calcareous chalk with cm-scale layers of silicified limestone. Core 54R is composed primarily of red to dark reddish brown calcareous chalk; however, the lowermost 4 cm of Section 54R-CC are composed of grayish green glauconitic sand. Varying amounts of clay are present throughout Cores 50R to 54R. In Cores 51R to 53R P-wave velocities increase, and in Core 54R magnetic susceptibility (MS) more than doubles. Cores 50R to 54R are Campanian in age. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew will now be tested every other day for COVID-19.

Daily Science Report for 21 February 2022

Location: Location: Hole U1579D (39°57.0725′S, 26°14.1793′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: Cores U1579D-43R to 51R advanced from 523.5 to 610.8 mbsf and recovered 68.4 m (78%).

Cores U1579D-39R to 45R are composed primarily of light greenish gray calcareous chalk with thinner layers of greenish gray claystone. There are occasional layers of light gray silicified limestone. Cores 46R to 49R are composed primarily of reddish brown and light brownish gray intervals of calcareous chalk with varying clay content. Bioturbation is moderate to intense throughout these cores. Cores U1597D-39R to 49R are Late Cretaceous in age, spanning from the Maastrichtian to the Campanian. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 20 February 2022

Location: Hole U1579D (39°57.0725′S, 26°14.1793′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: Cores U1579D-30R to 42R advanced from 397.4 to 523.5 mbsf and recovered 73.1 m (58%).

Cores U1579D-23R to 38R consist primarily of white to light greenish and pinkish gray to brown nannofossil chalk with varying clay content. Bioturbation is sparse to intense and small intervals of chert are present. The Cretaceous/Paleogene (K/Pg) boundary is present in Core 33R and is distinguished by a reddish-brown interval of calcareous ooze surrounded by white and light greenish gray calcareous chalk. Core 38R is Late Cretaceous in age. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew will now be tested every other day for COVID-19.

Daily Science Report for 19 February 2022

Location: Hole U1579D (39°57.0725′S, 026°14.1793′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: Cores U1579D-16R to 29R advanced from 261.6 to 397.4 mbsf and recovered 90.4 m (67%).

Cores U1579D-9R to 22R consist primarily of white to light gray and light greenish, pinkish gray nannofossil chalk and calcareous chalk with varying clay content. Bioturbation is low to intense with distinct burrows. Cores 9R to 22R span from the late Eocene to early Paleocene in age. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 18 February 2022

Location: Hole U1579D (39°57.0725′S, 026°14.1793′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: Hole U1579D was drilled down from 59.1 to 130 mbsf and the center bit was retrieved at 0245 h. Cores U1579D-2R to 15R advanced from 130.0 to 261.6 mbsf and recovered 105.6 m (80.29%).

Cores U1579D-2R to 8R consist of white to light brown to light greenish, bluish, and pinkish gray nannofossil chalk with varying clay content. Some silt size lithics are also present. Bioturbation is sparse to intense. Cores 2R to 8R span from the early Oligocene to the late Eocene in age, with the latest Eocene in Core 6R. Carbonate content for Holes U1579A and U1579B is generally high (>80%), with slightly lower carbonate content in light brown sediments coinciding with increased bioturbation. Throughout Site U1579 alkalinity continues to increase with depth. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew will now be tested every other day for COVID-19.

Daily Science Report for 17 February 2022

Location:

Hole U1579C (39°57.0588′S, 26°14.1785′E; water depth 2492.9 mbsl; proposed Site AP-10A)
Hole U1579D (39°57.0725′S, 26°14.1793′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: We continued waiting on weather until 0930 h, at which point we were able to bring the BHA to the rig floor, ending Hole U1579C at 1055 h. The RCB BHA was assembled and we began tripping pipe back to the seafloor. Hole U1579D was spudded at 2124 h and drilled down to 59.1 mbsf.

Scientists began writing reports for Site U1579. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 16 February 2022

Location: Hole U1579C (39°57.0588′S, 26°14.1785′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: Cores U1579C-9F to 21F advanced from 82.0 to 130.5 mbsf and recovered 48.8 m (112%). Short drilled intervals without recovery were made between 86.7–88.2, 102.3–103.3, and 115.4–116.4 mbsf for stratigraphic correlation. We then drilled down 31.5 m with the center bit to 162 mbsf to resume XCB coring. Cores U1579C-23X to 25X advanced from 162.0 to 186.9 mbsf and recovered 2.78 m (9.67%). At 1630 h we began pulling out of Hole U1579C and completed the pipe trip with the BHA almost to the rig floor at 2330 h when we had to stop to wait on weather.

Cores U1579C-2F to 21F consist primarily of light gray to white nannofossil ooze with varying foraminifer and pyrite content. Low to moderate bioturbation is observed. Some cores are highly disturbed by fall-in, voids, and fracturing. Cores 23X to 25X consist primarily of white nannofossil chalk, with some biosilica in Core 24X. The bottom of Hole U1579C is latest Eocene in age. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 15 February 2022

Location:

Hole U1579B (39°57.0565′S, 26°14.1729′E; water depth 2492.9 mbsl; proposed Site AP-10A)
Hole U1579C (39°57.0588′S, 26°14.1785′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: Cores U1579B-16F to 24F advanced from 99.3 to 141.6 mbsf and recovered 44.4 m (105%). Cores 23F and 24F required drillovers and had 100,000 lb overpulls. Cores U1579B-25X to 27X advanced from 141.6 to 167.2 mbsf and recovered 19.2 m (77%). We then pulled out of the hole, clearing the seafloor at 1643 h and ending Hole U1579B. The vessel was offset 10 m east and 10 m south, and Hole U1579C was spudded at 1720 h. We drilled down with the center bit to 56.5 mbsf and collected Cores U1579C-2F to 8F, advancing from 56.5 to 82.0 mbsf and recovering 22.7 m (97%).

Cores U1579B-8F through 27X consist primarily of white nannofossil ooze, with increasing clay content and bioturbation downcore. Drilling disturbance (biscuits) is observed in the XCB cores. Core 8F is late Oligocene in age, and the bottom of Core 27X is just above the Eocene/Oligocene boundary. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 14 February 2022

Location: Hole U1579B (39°57.0565′S, 26°14.1729′E; water depth 2492.9 mbsl; proposed Site AP-10A)

Science Update: The BHA and remaining parts of the core barrel were retrieved by 0045 h. The barrel parted at the lower thread pin and the majority of the barrel, including core liner and any sedimentary material, was not recovered. The BHA was made up, pipe was tripped back to the seafloor, and the vessel was offset 20 m north in preparation for Hole U1579B. At 0910 h Hole U1579B was spudded and the seafloor was established as 2504 mbrf. Core U1579B-1H recovered 9.97 m (105%). Cores 2H to 6H advanced 57 m, recovering 60.1 m (106%). A temperature measurement using the APCT-3 tool was taken on Core 4H. Based on conditions in Hole U1579A we switched to the half-length APC (HLAPC) system. Cores 7F to 15F advanced from 57 to 99.3 mbsf and recovered 43.3 m (102%).

Cores U1579A-7H and 8H consist primarily of white nannofossil ooze with varying foraminifer content. Core U1579B-1H consists of gray nannofossil-rich foraminifer ooze with sand sized grains of a dark material throughout and is lower Miocene age. Cores U1579B-2H to 7F consist primarily of white nannofossil ooze with varying foraminifer content spanning through the upper Oligocene. Magnetic susceptibility is low and alkalinity is increasing downhole. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 13 February 2022

Location: Hole U1579A (39°57.0512′S, 26°14.1497′E; water depth 2498.4 mbsl; proposed Site AP-10A)

Science Update: Pipe was tripped to 2476 mbrf with a seafloor depth of 2509.4 mbrf. Hole U1579A was spudded at 0440 h from 2508 mbrf. Core U1579A-1H was on deck at 0500 h with a recovery of 8.07 m. Cores 1H to 8H advanced from 0 to 74.6 mbsf and recovered 73.51 m (98.5%). Temperature measurements using the advanced piston corer temperature tool (APCT-3) were taken on Cores 4H and 7H. On Core 9H an overpull on the barrel was observed. After drilling over the barrel by 3 m, we attempted to pull the core barrel free again and were successful, but the core line was retrieved with no barrel attached. An attempt to fish the barrel was unsuccessful and the decision was made to abandon the hole. We began tripping the pipe and BHA, clearing the seafloor at 1735 h, and continuing toward the rig floor.

Cores U1579A-1H to 6H consist primarily of white nannofossil ooze with varying foraminifer content. The Oligocene/Miocene boundary is tentatively identified in Core 1H or 2H. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 12 February 2022

Location:

Underway to proposed Site AP-10A (Site U1579)
Site U1579 (39°57.0512′S, 26°14.1497′E)

Science Update: After completing the final 154 nmi of the 557 nmi voyage from Cape Town, South Africa, to proposed Site U1579, we arrived on site at 1430 h. We started lowering the thrusters at 1451 h and switched to full dynamic positioning (DP) mode at 1452 h. The rig floor was released for operations and commenced assembling the bottom-hole assembly (BHA) and preparing drill collars for the rotary core barrel (RCB) in Hole U1579C. The advanced piston corer/extended core barrel (APC/XCB) BHA was assembled and run down to 136.8 meters below rig floor (mbrf). We continued tripping pipe to 1147.6 mbrf through the rest of the evening and repaired a hose on the pipe racker while measuring pipe.

The science party continued final preparations for the first core on deck and the science office reviewed methods chapters. Surface seawater sampling (every 6 h) began outside the exclusive economic zone (EEZ) of South Africa. A safety meeting was held for staff and scientists that are involved in the use of hydrofluoric acid (HF). A practice run through of HF procedures in the laboratory was also conducted. Shipboard COVID-19 mitigation protocols continue to be followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 11 February 2022

Location: Underway to proposed Site AP-10A (Site U1579)

Science Update: The vessel completed 277 nmi, and a total of 403 nmi, of the 557 nmi voyage from Cape Town to proposed Site AP-10A (Site U1579) at an average speed of 11.5 kt. The estimated time of arrival on site is midday on 12 February.

The scientists continued preparing methods, orienting to the laboratories, and setting up instruments. Shipboard COVID-19 mitigation protocols are being followed. All members of the science party, staff, and crew were tested for COVID-19.

Daily Science Report for 10 February 2022

Location:

Repair Quay 3, Cape Town, South Africa
Underway to proposed Site AP-10A (Site U1579)

Science Update: The pilot boarded the ship at 0942 h, and the vessel departed Repair Quay 3 with the last line released at 1024 h. Our sea passage then began at 1048 h. At 1115 h, with the vessel at full throttle, the newly installed 50 kVA uninterruptible power supply (UPS) rejected the ship’s power and began running off batteries. The vessel was throttled back to half speed at 1116 h while the situation was diagnosed. Beginning at 1245 h, JRSO IT services were taken offline. The UPS was bypassed and regulated power was restored at 1445 h. The vessel returned to full speed at 1448 h and JRSO IT services were restored at 1715 h. The rest of the day was spent in transit and we completed 126 nmi of the 557 nmi voyage from Cape Town to proposed Site AP-10A (Site U1579). The estimated time of arrival on site is midday on 12 February.