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IODP Expedition 392

Agulhas Plateau Cretaceous Climate

Daily Science Report for 31 March 2022

Location: Underway for waiting on weather (midnight position 36°57.507′S, 22°13.437′E)

Science Update: We continued to wait on weather. During the day we changed our heading and began transiting back toward Site U1582 to resume coring possibly on 1 April. The science party continued to work on reports and prepare for the end of the expedition.


Daily Science Report for 30 March 2022

Location: Underway for waiting on weather (midnight position 35°48.900′S, 21°1.670′E)

Science Update: We continued to wait on weather. The science party worked on report edits for Site U1581 and began writing reports for Site U1582.


Daily Science Report for 29 March 2022

Location:

  • Hole U1582A (37°1.5002′S, 24°59.7168′E; water depth 3429.4 mbsl; proposed Site AP-07A)
  • Underway for waiting on weather (midnight position 35°16.500′S, 23°47.000′E)

Science Update: We continued to trip pipe back to the vessel, with the bit clearing the rig floor at 0455 h, ending Hole U1582A. The vessel was secured for transit, switched to cruise mode, and the thrusters were raised. We began a transit to the north at 1615 h to wait on weather. At 1818 h we turned to a westerly heading.

Cores U1582A-6R and 7R are composed primarily of plagioclase phyric basaltic pillow lava. Several intervals of light yellowish-brown to pale green limestone are present in the top of Core 6R.


Daily Science Report for 28 March 2022

Location: Hole U1582A (37°01.5002′S, 24°59.7168′E; water depth 3429.4 mbsl; proposed Site AP-07A)

Science Update: Hole U1582A was spudded on the sixth attempt, after five water cores. Core U1582A-1R was cut at 0405 h and recovered 1.9 m, placing the seafloor at 3429.4 mbsl. Cores U1582A-1R to 7R advanced from 0.0 to 48.0 mbsf and recovered 18.5 m (55%). Cores 6R and 7R were advanced as half cores. With bad weather approaching, we began to pull out of the hole at 1915 h in preparation to leave the site. By the end of the day we had tripped pipe back to 1673.8 mbrf.

Cores U1582A-1R to 4R are primarily composed of light yellowish-brown to brown nannofossil ooze (with clay and sand in Cores 3R and 4R). Pale brown and light brown silt intervals are present in Core 2R, and in Section 2R-1 there is a ~10 cm manganese nodule. There is another manganese nodule in the top of Core 5R and the remainder of Core 5R is light gray and pale yellow limestone. The first sections of Cores 1R and 5R are severely disturbed, mousse-like and fragmented respectively. Core 1R is Oligocene in age and Core 4R is Coniacian. The science party continued to edit reports and give summary presentations for Site U1581.


Daily Science Report for 27 March 2022

Location:

  • Underway to Site U1582 (proposed Site AP-07A)
  • Site U1582 (37°01.5001′S, 24°59.7180′E)

Science Update: We completed the remaining 152 nmi of our 239 nmi sea passage, arriving at Site U1582 at 1420 h. The thrusters were lowered and the vessel switched to DP mode by 1440 h. The PDR indicated that seafloor was 3384.4 mbsl. The BHA and a new C-7 RCB bit were prepared for Hole U1582A and the drill pipe was tripped to the seafloor. The first attempted core at 2340 h was empty (water core).

The science party continued to edit reports and began giving summary presentations for Site U1581.


Daily Science Report for 26 March 2022

Location:

  • Hole U1581B (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)
  • Underway to Site U1582 (proposed Site AP-07A)

Science Update: We ran the Schlumberger triple combo tool down to 1300.0 mbrf before an electrical fault occurred. The tool was pulled out of the hole and was back on the rig floor by 0250 h. It was decided to not make any further attempts at downhole logging at Site U1581. The remainder of the drill pipe was tripped out of the hole, clearing the seafloor at 0555 h and the rig floor at 1510 h, ending Hole U1581B. The rig floor was secured for transit, we switched out of full DP mode, and the thrusters were raised. The sea passage toward Site U1582 (proposed Site AP-07A) began at 1548 h. During the remainder of the day, 87 nmi of the 239 nmi transit were completed. The estimated time of arrival on site is 1430 h on 27 March.

The science party continued to edit reports and received a presentation on the scientific objectives of the next planned site (proposed Site AP-07A).


Daily Science Report for 25 March 2022

Location: Hole U1581B (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: The drill pipe was tripped up to 77.8 mbsf in preparation for downhole logging. The Schlumberger Versatile Seismic Imager (VSI) tool was made up and we began running into the hole at 0415 h. At 222.4 mbsf the tool tagged a ledge. The tool was worked up and down unsuccessfully and brought back to the rig floor at 1120 h. The drill pipe was then tripped back down to 408.5 mbsf to avoid other potential ledges and still allow downhole logging of the lower portion of the hole. Due to the limited number of daylight hours remaining, the Schlumberger triple combo tool was made up. There was a problem with powering up the tool string; however, this was repaired and we began running into the hole with the tool at 1630 h. With the tool lowered to 2606.8 mbrf, an electrical fault occurred. The tool was pulled out of the hole and was back on the rig floor by 2010 h. Troubleshooting suggested that a new head was needed for the tool. The repair was made, the tool was powered up, and we once again began running into the hole with the triple combo.

The science party continued to edit reports and received an introduction to postcruise sample request software.


Daily Science Report for 24 March 2022

Location: Hole U1581B (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581B-69R to 74R advanced from 938.9 to 997.1 mbsf and recovered 38.6 m (66%). Mud sweeps were pumped on Cores 70R and 71R. Two additional mud sweeps were pumped after Core 74R in preparation for downhole logging. The bit was released in the bottom of the hole at 1835 h and the hole was displaced with heavy mud. We began tripping the pipe toward the seafloor and had pulled up to 480.8 mbsf.

Cores U1581B-62R to 74R consist primarily of very dark greenish-gray to greenish-black claystone with less common intervals of siltstone. Siderite, pyrite, and shell fragments are present in some sections. Intervals of very dark gray to light gray and dark grayish-brown limestone are present in Cores 68R through 71R. Cores 62R to 74R are Campanian in age.


Daily Science Report for 23 March 2022

Location: Hole U1581B (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581B-59R to 68R advanced from 841.9 to 938.9 mbsf and recovered 69.7 m (72%). Mud sweeps were pumped on Cores 61R, 64R, and 67R.

Cores U1581B-53R to 61R consist primarily of very dark greenish-gray to greenish-black siltstone, and claystone. Shell fragments and siderite are present in many sections of Cores 60R and 61R. The cores are Campanian in age.


Daily Science Report for 22 March 2022

Location: Hole U1581B (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581B-48R to 58R advanced from 735.2 to 841.9 mbsf and recovered 86.8 m (81%). Mud sweeps were pumped on Cores 49R, 52R, 55R, and 58R.

Cores U1581B-43R to 52R consist primarily of very dark greenish-gray to greenish-black sandstone, siltstone, and claystone. Pyrite and shell fragments are present in many sections. The cores are Campanian in age.


Daily Science Report for 21 March 2022

Location: Hole U1581B (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581B-37R to 47R advanced from 628.5 to 735.2 mbsf and recovered 100.8 m (95%). Mud sweeps were pumped on Cores 40R, 43R, and 46R.

Cores U1581B-34R to 42R consist primarily of very dark greenish-gray to greenish-black sandstone, siltstone, and claystone. Nannofossil content varies throughout the cores and foraminifers are present in Core 41R. Pyrite and shell fragments are also present in many sections and glauconite appears occasionally. The cores are Campanian in age.


Daily Science Report for 20 March 2022

Location: Hole U1581B (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581B-26R to 36R advanced from 521.8 to 628.5 mbsf and recovered 96.9 m (91%). Mud sweeps were pumped on Cores 28R, 31R, 34R, and 37R.

Cores U1581B-23R to 33R consist primarily of very dark greenish-gray to greenish-black sandstone, siltstone, and claystone. Nannofossil content varies throughout the cores, and glauconite, pyrite, and shell fragments are also present in many sections. There are occasional greenish-gray calcareous chalk intervals. The cores are Cretaceous in age, spanning into the Campanian.


Daily Science Report for 19 March 2022

Location: Hole U1581B (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581B-16R to 25R advanced from 424.8 to 521.8 mbsf and recovered 69.5 m (72%). Mud sweeps were pumped on Cores 19R and 25R.

Cores U1581B-13R to 22R consist primarily of dark greenish-gray and greenish-black sand, silt, and clay. Glauconite and pyrite are commonly present in Cores 19R to 22R. Cores 13R to 22R span from the Paleocene to the Cretaceous in age.


Daily Science Report for 18 March 2022

Location: Hole U1581B (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581B-6R to 15R advanced from 327.8 to 424.8 mbsf and recovered 52.6 m (54%). Mud sweeps were pumped on Cores 8R and 14R.

Cores U1581B-3R and 4R consist primarily of greenish-gray and dark greenish-gray silt with varying nannofossil and clay content. Some thin sand layers are also present and drilling disturbance (primarily biscuiting) is slight to severe. Core 5R consists primarily of brown clayey silt. Cores 6R through 12R are greenish-gray to dark greenish-gray. Core 6R consists primarily of silt, followed by a transition to primarily nannofossil ooze and chalk in Cores 8R to 10R, and a return to silt in Cores 11R and 12R. Glauconite and pyrite are observed throughout the cores. Cores 3R to 12R span from the Oligocene to the Paleocene in age.


Daily Science Report for 17 March 2022

Location: Hole U1581A (35°40.8660′S, 29°39.0192′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: We continued to trip pipe to the seafloor and Hole U1581B was spudded at 0230 h. An RCB barrel with a center bit was used to drill ahead to 289 mbsf, with several mud sweeps during the drill down. The center bit was recovered and Cores U1581B-2R to 5R advanced from 289.0 to 327.8 mbsf and recovered 25.5 m (66%).

Core U1581B-2R consists of dark grayish-green and greenish-gray clayey silt with zeolite. There are several intervals of nannofossil-rich silt with glauconite.


Daily Science Report for 16 March 2022

Location:

  • Underway to Site U1581 (proposed Site TB-01A)
  • Site U1581 (35°40.886′S, 29°39.000′E)

Science Update: We completed the remainder of our sea passage to Site U1581, arriving at 1156 h, with thrusters down and the vessel switched to DP mode by 1216 h. The rig floor crew began making up the RCB BHA and the pipe was tripped to 4499.7 mbrf before a slip and cut of the drilling line was started.

The science party continued to edit reports.


Daily Science Report for 15 March 2022

Location:

  • Underway to Port Elizabeth, South Africa
  • Underway to Site U1581 (proposed Site TB-01A)

Science Update: We completed the remainder of our sea passage to Port Elizabeth, South Africa, arriving at 0700 h. We reduced speed and waited offshore. Clearance for the departing crew member was received at 1300 h and they disembarked the vessel via launch at 1402 h. We then began the transit to Site U1581, with 125 nmi remaining at the end of the day. The estimated time of arrival at Site U1581 is midday on 16 March.

The science party continued to edit reports.


Daily Science Report for 14 March 2022

Location:

  • Hole U1581A (35°40.8654′S, 29°39.0055′E; water depth 4591.4 mbsl; proposed Site TB-01A)
  • Underway to Port Elizabeth, South Africa

Science Update: Pipe was tripped back to the vessel, clearing the rig floor at 0825 h and ending Hole U1581A. The rig floor was secured for transit to Port Elizabeth, South Africa, for a compassionate evacuation. After continued attempts to retrieve the acoustic positioning beacon, it was deemed lost. We switched out of full DP mode, the thrusters were raised, and the sea passage toward Port Elizabeth, South Africa, began at 1014 h. During the remainder of the day 144 nmi of the 225 nmi transit were completed.

The science party continued to edit reports.


Daily Science Report for 13 March 2022

Location: Hole U1581A (35°40.8654′S, 29°39.0055′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581A-32F to 38F advanced from 243.2 to 276.1 mbsf and recovered 33.3 m (101%). We then switched to the XCB system. Cores 39X to 41X advanced from 276.1 to 300.5 mbsf and recovered 6.0 m (30%). Based on recovery, we stopped coring with the XCB system and began to trip the pipe out of the hole. The pipe cleared the seafloor at 1945 h and we continued to trip through the water column.

Cores U1581A-28H to 41X consist primarily of greenish-gray and dark greenish-gray layers of silt and sand. Nannofossils are present in many of the sections, and in Cores 39X and 40X there are intervals of nannofossil ooze and chalk. The cores span from the Miocene to Oligocene in age.


Daily Science Report for 12 March 2022

Location: Hole U1581A (35°40.8654′S, 29°39.0055′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581A-19H to 24H advanced from 162.5 to 207.2 mbsf and recovered 34.6 m (71%). Pressure in the pipe increased while drilling the rathole of Core 24H. A mud sweep was pumped and the core barrel was pulled back to the surface while the crew continued to circulate and condition the hole with an additional two mud sweeps. When the core barrel returned to the rig floor it had recovered 8.11 m (Core 25G). A fray in the core line was also discovered and this was repaired. Cores 26H to 29H advanced from 207.2 to 233.8 mbsf and recovered 26.8 m (101%). We then switched to the HLAPC system. Cores 30F to 31F advanced from 233.8 to 243.2 and recovered 9.2 m (98%).

Cores U1581A-14H to 23H are composed of dark greenish-gray and greenish-gray nannofossil ooze, sand, and silt layers. Bioturbation is generally absent to low. Cores 24H, 25G, and 26H are composed primarily of light brownish-gray and brown silt and sand, with some calcareous and nannofossil ooze in Core 26H. Core 27H is composed of greenish-gray silt and sand. Drilling disturbance is common in the sand intervals. Cores 14H to 27H span from the Pleistocene to the Miocene in age.


Daily Science Report for 11 March 2022

Location: Hole U1581A (35°40.8654′S, 29°39.0055′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: Cores U1581A-3H to 18H advanced from 16.4 to 162.5 mbsf and recovered 146.6 m (100%). Temperature measurements using the APCT-3 tool were taken on Cores 4H, 7H, 10H, and 13H.

Cores U1581A-1H to 13H are composed primarily of light greenish-gray to greenish-gray nannofossil ooze, with biosilica in Core 1H. Bioturbation is generally absent to low and intervals of dark gray sand (centimeters to tens of centimeters) are more common and thicker downhole. Drilling disturbance is common in the sand intervals. The cores are Pleistocene in age.


Daily Science Report for 10 March 2022

Location: Hole U1581A (35°40.8654′S, 29°39.0055′E; water depth 4591.4 mbsl; proposed Site TB-01A)

Science Update: The APC/XCB BHA was assembled and we began tripping pipe to the seafloor. An acoustic positioning beacon was deployed and the precision depth recorder (PDR) indicated that seafloor was 4578.2 mbsl. We attempted to shoot the first APC core from 4573.8 mbsl; however, this resulted in no recovery (water core). Two additional attempts from 4578.8 and 4583.8 mbsl also resulted in no recovery. Hole U1581A was successfully spudded at 2115 h, recovering 6.88 m, and the seafloor was calculated at 4591.4 mbsl. Cores U1581A-1H and 2H advanced from 0 to 16.4 mbsf and recovered 16.9 m (103%).

The science party presented further results from Site U1580 and continued to edit reports.


Daily Science Report for 9 March 2022

Location:

  • Underway to proposed Site TB-01A (Site U1581)
  • Site U1581 (35°40.866′S, 29°39.006′E)

Science Update: After completing the final 243 nmi of the 338 nmi voyage to proposed Site TB-01A (Site U1581), we arrived on site at 2345 h. The thrusters were lowered and we switched to full DP mode at 2357 h.

The science party began presenting results from Site U1580 and continued to edit reports.


Daily Science Report for 8 March 2022

Location:

  • Hole U1580B (40°47.1542′S, 26°36.4282′E; water depth 2560.3 mbsl; proposed Site AP-09B)
  • Underway to proposed Site TB-01A (Site U1581)

Science Update: Cores U1580B-3R to 5R advanced from 48.7 to 77.8 mbsf and recovered 16.3 m (56%). We then began tripping pipe back to the vessel, clearing the seafloor at 0710 h and the rig floor at 1430 h, ending Hole U1580B. The rig floor was secured for transit, the thrusters were raised, and the transit to proposed Site TB-01A (Site U1581) began at 1524 h. We completed 95 nmi of the 338 nmi voyage. The estimated time of arrival at Site U1581 is 2330 h on 9 March.

Cores U1580B-2R to 5R consist primarily of light greenish-gray nannofossil chalk with varying clay content. Bioturbation is moderate throughout the cores and pyrite is common in Core 5R. The cores span from the late Eocene to early Paleocene in age.


Daily Science Report for 7 March 2022

Location:

  • Hole U1580A (40°47.1535′S, 26°36.4137′E; water depth 2560.3 mbsl; proposed Site AP-09B)
  • Hole U1580B (40°47.1542′S, 26°36.4282′E; water depth 2560.3 mbsl; proposed Site AP-09B)

Science Update: The first pass of basement with the UBI tool was successful to 504.5 mbsf. At the start of the second pass the transducer subassembly motor began stuttering and sticking, most likely from settled debris from higher in the hole. The UBI was brought to the surface and we tripped the remainder of the pipe out of Hole U1580A, clearing the seafloor at 0150 h. Pipe was tripped back to the ship and Hole U1580A ended at 0705 h. The BHA and a new C-4 RCB bit were prepared for Hole U1580B. A slip and cut was performed on the drilling line and pipe was tripped back to the seafloor. The vessel was offset 20 m to the east and an RCB core barrel with a center bit was installed. Hole U1580B was spudded at 1710 h and drilled without recovery to 40 mbsf before recovering the center bit. Core U1580B-2R advanced from 40.0 to 48.7 mbsf and recovered 7.5 m (86%).

The science party received a presentation from the Co-Chief Scientists on the scientific objectives of proposed Site TB-01A (Site U1581) and continued to edit reports for Site U1579.


Daily Science Report for 6 March 2022

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

Science Update: The Schlumberger triple combo tool string logged downhole to 524.2 mbsf and was retrieved at 0630 h. The Schlumberger Formation MicroScanner (FMS) tool was prepared and run into the hole at 0855 h. A two-pass downhole logging run was completed to 521.5 mbsf and the tool was out of the hole by 1535 h. The Ultrasonic Borehole Imager (UBI) tool was made up and run into the hole, beginning a first pass of basement before midnight.

Cores U1580A-67R and 68R consist primarily of medium and coarse grained dolerite to plagioclase-olivine phyric dolerite. There is a small interval of dark grayish-blue chert in the top of Core 68R.


Daily Science Report for 5 March 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-63R to 68R advanced from 495.1 to 533.9 mbsf and recovered 33.7 m (92%). The bit was released in the bottom of the hole at 0715 h and the hole was displaced with heavy mud. The pipe was tripped back to 80.7 mbsf and the Schlumberger triple combo tool was prepared and we began running into the hole.

Core U1580A-61R is composed primarily of gray to dark grayish brown siltstone/claystone and calcareous chalk. Sections 61R-1 and CC contain small intervals of basalt. Core 62R is composed of dark gray siltstone in the uppermost interval of Section 1 and is composed of basalt throughout the rest of the core. Cores 63R to 65R are composed primarily of medium grained plagioclase to olivine phyric basalt. Core 66R is composed of basalt in the uppermost sections before transitioning to coarse grained dolerite.


Daily Science Report for 4 March 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-53R to 62R advanced from 446.6 to 495.1 mbsf and recovered 30.03 m (62%).

Cores U1580A-52R to 56R are composed primarily of fine to medium grain plagioclase phyric basalt. The lowermost section of Core 56R contains chert and silicified limestone. Core 57R is composed primarily of gray to dark gray calcareous chalk with low to intense bioturbation. The calcareous chalk continues into the uppermost interval of Section 58R-1 and the remainder of Core 58R is composed of basalt. Core 59R is primarily composed of basalt with a small amount of chert and calcareous chalk. Core 60R is composed primarily of dark gray to very dark gray calcareous chalk with moderate bioturbation. Sedimentary intervals of Cores 52R to 60R span the Late Cretaceous.


Daily Science Report for 3 March 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-49R to 52R advanced from 427.2 to 446.6 mbsf and recovered 16.49 m (85%).

Cores U1580A-47R to 51R are composed primarily of fine to medium grained basalt. In the bottom of Core 48R there is an interval of baked limestone, and the top several centimeters of Core 49R are composed of sandstone. Section 51R-3 is composed primarily of broken chert pieces, with basalt in the bottom.


Daily Science Report for 2 March 2022

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

Science Update: Following the failed recovery of any material from Core U1580A-44R, the deplugging tool was dropped twice. Cores 45R to 48R advanced from 408.6 to 427.2 mbsf and recovered 13.4 m (77%).

Cores U1580A-38R and 39R are composed primarily of greenish-gray to bluish-black to dark bluish-gray glauconitic sandstone/siltstone/claystone. Bioturbation is absent to high. Cores 40R to 42R are composed primarily of greenish-gray to pinkish-gray calcareous chalk with layers of dark greenish-gray calcareous sandstone/siltstone and brown chert throughout. Core 43R recovered 0.15 m and is composed of chert and aphyric basalt. Core 44R recovered no material. Core 45R is composed of clinopyroxene phyric basalt in Sections 1 and 2 before transitioning in Section 3 to baked bluish -gray chert and silicified limestone. Core 46R is composed primarily of light reddish-gray silicified limestone and light gray to reddish-gray calcareous siltstone; however, Section 46R-CC is composed of aphyric basalt. Cores 38R to 46R span the Late Cretaceous in age, with Core 46R placed in the Turonian.


Daily Science Report for 1 March 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-37R to 42R advanced from 349.2 to 407.4 mbsf and recovered 42.3 m (73%). Cores 43R and 44R were cored by time (2 h each) and had penetration rates of less than 1 m/h. Core 43R advanced 0.2 m and recovered 0.15 m. Core 44R advanced 1 m and recovered nothing.

Cores U1580A-33R to 35R consist primarily of dark greenish gray to greenish black zeolitic sandstone/siltstone/claystone with glauconite. Bioturbation is sparse to moderate and some shell fragments are observed. Cores 36R and 37R are primarily composed of very dark greenish gray to greenish black glauconitic sandstone/siltstone/claystone and thin lamina are common. Cores 33R to 37R span the Late Cretaceous in age with Core 37R likely in the Coniacian.