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IODP Expedition 399

Building Blocks of Life, Atlantis Massif


Daily Science Report for 30 April 2023

Location: Hole U1309D (30°10.1195′N, 42°7.1131′W; water depth 1644.9 m)

Science Update: Today we recovered Cores U1309D-305R through 309R from 1454.6 mbsf to 1478.6 mbsf. We recovered a total of 9.52 m from the 24.0 m cored interval, with core recoveries ranging from 27% to 66% (average of 40% recovery). 30 bbl mud sweeps were pumped every ~5 m.

Cores U1309D-300R through 305R consist predominantly of slightly to moderately altered, coarse to medium-grained olivine-bearing gabbro, with intervals of sparsely olivine-bearing gabbro, orthopyroxene-bearing gabbro, aphyric and sparsely olivine plagioclase phyric diabase, and leucocratic diorite.


Daily Science Report for 29 April 2023

Location: Hole U1309D (30°10.1195′N, 42°7.1131′W; water depth 1644.9 m)

Science Update: Today we recovered Cores U1309D-299R through U1309D-304R from 1425.2 to 1454.6 mbsf. We recovered a total of 20.18 m from the 29.4 m cored interval with core recoveries ranging from 26% to 98% (average of 69% recovery).

Cores U1309D-299R through U1309D-302R consist of slightly to moderately altered, coarse to fine-grained olivine gabbro and (sparsely) olivine-bearing gabbro, subordinate diabase, and one ~10 m interval of leucocratic diorite.


Daily Science Report for 28 April 2023

Location: Hole U1309D (30°10.1195′N, 42°7.1131′W; water depth 1644.9 m)

Science Update: Assembly of the RCB BHA with a new C7 bit was complete at 0130 h. The drill string and subsea camera were deployed, and at 0525 h, Hole U1309D was reentered for the third time on this expedition. The camera was retrieved and the bit lowered to a hard tag at 1410.0 mbsf. We dropped a core barrel, washed to 1415.5 mbsf, and began deepening Hole U1309D from where IODP Expedition 305 left it. By midnight we had recovered Cores U1309D-297R and U1309D-298R with 6.81 m recovery from a 9.7 m cored interval (70% recovery).

Cores U1309D-297R and U1309D-298R consist of coarse to fine-grained olivine gabbro and olivine-bearing gabbro, subordinate diabase, and one thin interval of diorite.


Daily Science Report for 27 April 2023

Location: Hole U1309D (30°10.1195′N, 42°7.1131′W; water depth 1644.9 m)

Science Update: The drill string and the subsea camera were lowered to the seafloor, and at 0030 h Hole U1309D was reentered for the second time on this expedition. The camera and Niskin water sample bottles were recovered and the drill string was run further into the hole. At 0800 h, the bit tagged the top of the fill at 1379 mbsf (~37 m of fill). Milling and washing downhole proceeded expeditiously, the first 7–8 m at 8 m/h, and the remainder at 30 m/h. At 1007 h, the bit was at the previously reported bottom of Hole U1309D at 1415.5 mbsf. The first 10 min of milling at the bottom indicated erratic torque, presumed to be the result of encountering metal pieces lost on a previous expedition. The subsequent 3.5 h of milling indicated low and steady torque. The pipe was raised and lowered repeatedly for 1 h to fill the junk baskets, and a 30 bbl mud sweep completed cleaning operations in Hole U1309D. Retrieval of the drill string began at 1515 h, and at 2200 h, the bit arrived at the rig floor where the junk baskets were emptied. At 2315 h, the rig crew began assembling the RCB BHA with a new C7 bit.

The material recovered in the junk baskets during the hole cleaning operation was laid out in the Core Splitting Laboratory. It included two dozen 2–7 cm gabbroic rock pieces, bags of cuttings less than 1 cm in size, dozens of conspicuous chips of crystalline anhydrite or gypsum up to 1 cm size, and several metal pieces, including three 5 cm × 5 cm chunks. The rock pieces and cuttings were created during previous drilling on Expeditions 304 and 305. The metal pieces are most likely from the wireline logging tool that became damaged when it was pulled back into the drill pipe at the end of Expedition 340T ~12 years ago. The anhydrite or gypsum is speculated to have formed in the reentry cone over the past 12 years, based on its absence in the cored formation and the subsea camera footage showing the throat of the reentry cone plugged with whitish material before we reentered.


Daily Science Report for 26 April 2023

Location: Hole U1309D (30°10.1195′N, 42°7.1131′W; water depth 1644.9 m)

Science Update: The ascent of the Multi-Temperature Fluid Sampler (MTFS) and Elevated Temperature Borehole Sensor (ETBS) continued, and the tools arrived back on the rig floor at 0045 h. The tools were rigged down and the ETBS was removed from the MTFS and connected to the two Kuster samplers. The two Kuster sampler clocks were set to sample at 411 mbsf (0310 h) and 739 mbsf (0330 h). The Kuster assembly was lowered down the drill pipe at 0207 h and was back at the rig floor at 0500 h. A second run of the Kuster assembly was configured to sample at 1111 mbsf (0823 h) and 1320 mbsf (0846 h). It was lowered down the drill string at 0706 h and was back on the rig floor at 1225 h. The Kuster tools with ETBS traveled at a rate of 10 m/min in the hole, stopping for 3 min every 100 m for temperature check measurements. The drill string was retrieved with the drill bit clearing the rig floor at 1620 h, ending BHA run number 1 in Hole U1309D.

The next task consists of removing a few tens of meters of fill from previous drilling in Hole U1309D on IODP Expeditions 304 and 305, as well as a logging caliper presumed to have been left in the hole at the end of IODP Expedition 340T. A BHA was made up with a 9⅝ inch concave mill and two junk baskets and lowered to the seafloor at 1845 h. At 2120 h the subsea camera and two Niskin water samplers were deployed. At midnight we were ready to reenter Hole U1309D for the second time.

The fluid science team received water samples from all three fluid sampling tool runs, with various success rates. Out of the 11 MTFS sample chambers, two were completely full, two were empty, and the remainder were partially filled with water. The tool cavities were filled with debris consisting of sand-sized rock fragments and large amounts of black powder. The failure of some sample chambers to be filled completely is attributed to the debris on the outside of the O-rings preventing the piston to extend completely. Three of the four Kuster tool samples were successful. The failure of the fourth is also attributed to the debris in the hole. The water samples analyzed so far have a pH and alkalinity significantly different from seawater. The ETBS run with the MTFS yielded a good quality temperature log, closely following the one obtained during Expedition 340T using the Modular Temperature Tool (MTT) on the wireline logging string. However, the data from the subsequent two ETBS deployments with the Kuster tools are problematic, possibly due to tool failure.


Daily Science Report for 25 April 2023

Location: Hole U1309D (30°10.1195′N, 42°7.1131′W; water depth 1644.9 m)

Science Update: The rig crew continued to disassemble and lay out the reentry system that had to be returned from Hole U1601B, including casing, cone, HRT, and BHA. The ship arrived at Hole U1309D in DP mode after moving 2 nmi. From 0715 h to 0800 h, the rig was serviced in preparation for operations in Hole U1309D. A BHA was assembled with a clean-out bit and no float valve for deployment of the MTFS as well as the Kuster fluid sampler, both with the ETBS attached to the bottom. We started to lower the drill string at 0830 h and deployed the subsea camera with two Niskin water sampling bottles at 1115 h. With the ship offset ~20 m from Hole U1309D, the “pig” tool was pumped through the drill string to clean out rust from the inside. At 1505 h, the drill string reentered Hole U1309D. The Niskin bottles were triggered, and the camera frame and bottles were retrieved to the rig floor by 1620 h. Next, the MTFS was prepared on the catwalk, rigged up with the ETBS on the rig floor, and lowered down the drill pipe starting at 1815 h. During the remainder of the day, the MTFS assembly descended, then ascended at a rate of 10 m/min, with 3 min temperature check stops every 100 m. The tool string tagged bottom at 1389 mbsf, indicating a possible ledge, or a ~36 m thick fill at the bottom of Hole U1309D.

The fluid science team was busy receiving the Niskin water samples and preparing for the MTFS and Kuster tool deployments. Other laboratory teams described thin sections and conducted various measurements and experiments.


Daily Science Report for 24 April 2023

Location: Hole U1601B (proposed Site AMDH-02A; 30°7.9339′N, 42°7.2171′W; water depth 850 m)

Science Update: We continued to drill-in the reentry system in Hole U1601B. Sepiolite mud sweeps were pumped every ~4 m. At 1215 h we reached the target depth of 26.0 mbsf. The go-devil trigger tool for the HRT was dropped at 1225 h and pumped down the drill string with 25 strokes/min until it landed at 1235 h, with a pressure drop indicating that the release occurred. However, several attempts to pull the stinger subassembly out of the casing subassembly were unsuccessful despite turning the pumps on and off several times to work the underreamer. It appeared that the underreamer arms didn’t fully retract and were caught on the bottom of the casing. At 1430 h the decision was made to retrieve the subsea cameras and then the entire reentry assembly back to the rig floor. The camera was back at 1525 h. The drill string with the reentry system was pulled at reduced pipe tripping speed and was in the moonpool at 1845 h. The rig crew spent the rest of the night disassembling the reentry system. The stinger bit was at the rig floor at 2353 h.

The rig crew will need time to assess the situation and come up with an alternative method for deploying a reentry system, and to build that system. We decided that while this was happening, we would move to Hole U1309D and conduct the fluid sampling program there, including the Niskin bottles on the subsea camera frame for bottom water samples, the Novel Multi-Temperature Fluid Sampler (MTFS), the Kuster fluid sampler, and the Elevated Temperature Borehole Sensor (ETBS) attached to the latter two downhole fluid samplers. The ship began its DP move to Hole U1309D at 2353 h.

The scientists met for presentations of the reentry equipment and process as well as coring and fishing tools likely to be deployed on this expedition, methods to monitor and document contamination in microbiology samples, and pool sampling strategies for shipboard and shorebased geochemical analyses.


Daily Science Report for 23 April 2023

Location: Hole U1601B (proposed Site AMDH-02A; 30°7.934′N, 42°7.217′W; water depth 850 m)

Science Update: Assembly of the reentry system continued. The ~22 m long 13⅜ inch casing string, HRT, landing platform, and free-fall funnel (FFF) were prepared in the moonpool area. The stinger BHA, including mud motor and underreamer, was assembled and tested. The underreamer arms opened at 35 strokes/min (spm) and 300 psi pump pressure, and they closed at 0 spm. All parts were assembled, and the reentry system was lowered to the seafloor at 1015 h. Drilling in Hole U1601B began at 1455 h. By midnight, the casing had been drilled-in to 10.9 mbsf. A 10 bbl mud sweep was pumped at 6 mbsf.

The scientists received an introduction to the new XSCAN radiograph system and an update on outreach activities. They met to review and sample Cores U1601A-5R through U1601A-12R for shipboard analyses, including thin section descriptions, geochemical analyses, and physical and magnetic properties measurements.


Daily Science Report for 22 April 2023

Location: Hole U1601A (proposed Site AMDH-02A; 30°7.9260′N, 42°7.2255′W; water depth 850 m)

Science Update: The rig crew continued attempts to free the stuck drill bit at 49.9 mbsf, maximizing overpull, torque, and pump pressure, and offsetting the vessel 90 m north trying to break the drill pipe connection, without success. At 0045 h the decision was made to deploy the Schlumberger pipe severing tool. Two severing attempts at 0705 h and 1035 h failed. The third attempt at 1243 h succeeded in severing the pipe at 10.1 mbsf. The tool was back on deck at 1330 h. The drill string was retrieved and the end of pipe cleared the rig floor at 1730 h, ending operations at Hole U1601A and starting Hole U1601B.

The ship remained at the Hole U1601A location for the assembly of the drill-in casing system. The upper guide horn was removed to create the space needed to assemble the system. During the remainder of the night, the hydraulic release tool (HRT) was readied, and the 13⅜ inch casing was rigged up.


Daily Science Report for 21 April 2023

Location: Hole U1601A (proposed Site AMDH-02A; 30°7.9260′N, 42°7.2255′W; water depth 850 m)

Science Update: Coring in Hole U1601A continued until 1245 h. Cores U1601A-7R through U1601A-12R advanced 29.1 m to 60.6 mbsf and recovered 11.3 m of core. Core recovery ranged from 8% to 72%, with an average of 39%. 20 bbl of sepiolite mud were pumped after each core recovery (every 4–5 m). Although the objective of drilling a 50 m pilot hole had been achieved, we hoped to advance the hole further for at least another day given the increasing rate of recovery of the sought-after mantle rocks. However, at 1245 h and 56.3 mbsf, the bit became stuck. The rest of the night was spent trying to free the bit at ~50.3 mbsf by maximizing overpull, torque, and pump pressure, and attempting to move the drill string every hour.

The recovered rocks consist of highly to completely serpentinized harzburgite and dunite, as well as a few thin intervals of gabbronorite and diorite. Abundant metamorphic veins of up to three generations, filled with serpentine and oxides, were noted.


Daily Science Report for 20 April 2023

Location: Hole U1601A (proposed Site AMDH-02A; 30°7.9260′N, 42°7.2255′W; water depth 850 m)

Science Update: Coring in Hole U1601A continued. Core U1601A-2R was advanced 9.7 m and subsequent Cores U1601A-3R through U1601A-6R were advanced ~4.8 m each to a total depth of 31.5 meters below seafloor (mbsf). Recovery ranged from 1% to 25%, with an average of 11%. Sepiolite mud was pumped at 25 mbsf (20 bbl) and 31 mbsf (50 bbl).

The recovered rocks include diabase in Cores U1601A-2R and U1601A-3R, and serpentinized harzburgite and dunite in Cores U1601A-4R and U1601A-5R.


Daily Science Report for 19 April 2023

Location: Hole U1601A (proposed Site AMDH-02A; 30°7.9260′N, 42°7.2255′W; water depth 850 m)

Science Update: We arrived at Site U1601 at 0530 h, completing the 937 nmi transit from Ponta Delgada. The ship was in dynamic positioning (DP) mode by 0551 h, starting operations at Site U1601.

The objective at Site U1601 is to core a 200 m deep hole through the detachment fault at the Atlantis Massif. We chose IODP Site 357-M0069, which was drilled with the British Geological Survey RockDrill 2 during the RSS James Cook expedition in 2015, as a reference location. The plan is to install a reentry system at Site U1601, which requires drilling a ~50 m deep pilot hole to assess the formation.

The rig crew assembled a bottom-hole assembly (BHA) with a rotary core barrel (RCB) and C-7 drill bit and lowered the drill string to 854 meters below rig floor (mbrf) near the seafloor. The subsea camera was deployed at 1150 h for a brief seafloor survey. Site M0069 was immediately located thanks to several meters of pipe sticking out of the 2015 hole as well as various skid marks and sampling spots left by the remotely operated vehicle (ROV) Jason in 2018. Our survey line extended 60 m southwest of Site M0069 and showed sand waves all over the seafloor, as also seen more clearly on the 2018 ROV footage. No prohibitive obstructions or hazards were identified. After triggering the two Niskin bottles attached to the camera frame to collect bottom water samples and tagging the seafloor at 861 mbrf, the camera and samples were retrieved. Back on the ship, the Niskin water samples were immediately subsampled by the scientists for shipboard and shorebased analyses.

At 1810 h operations in the pilot Hole U1601A began by pushing the bit into the sediment without rotation for 2.4 m. The recovered barrel for Core U1601A-1R was empty. By midnight, coring had advanced 3.7 m.


Daily Science Report for 18 April 2023

Location: Underway to proposed Site AMDH-02A

Science Update: Today we traveled 268 nmi of the 937 nmi transit to proposed Site AMDH-02A. Our expected time of arrival is 0600 h on 19 April. The scientists received an introduction to curatorial procedures, continued their laboratory preparations, and began drafting the method descriptions for their work.


Daily Science Report for 17 April 2023

Location: Underway to proposed Site AMDH-02A

Science Update: Today we traveled 262 nmi of the 937 nmi transit to proposed Site AMDH-02A. Our expected time of arrival is now 0600 h on 19 April. The scientists received a presentation on the scientific reports to be written during the expedition, guidelines on how to write them, and workflow information on collaborative content generation and editing. Scientists also received training on operating the multisensor core loggers, microscopy, and imaging. Some scientists continued template preparations for core description while others refined plans for fluid subsampling and analysis.


Daily Science Report for 16 April 2023

Location: Underway to proposed Site AMDH-02A

Science Update: Today we traveled 244 nmi of the 937 nmi transit to proposed Site AMDH-02A. Our expected time of arrival is 1200 h on 19 April. At 1330 h senior personnel from SIEM Offshore met with the science management team for the pre-spud meeting where details of the upcoming operations at proposed Site AMDH-02A were discussed. Some of the scientists received further core description training and then held workshops to configure the description templates. Other scientists discussed fluid sampling and X-ray fluorescence (XRF) measurement protocols. All scientists participated in rig floor tours.


Daily Science Report for 15 April 2023

Location: Underway to proposed Site AMDH-02A

Science Update: One individual disembarked the vessel. The captain held the first boat drill at 1030 h. Port call activities ended and departure from Ponta Delgada began at 1324 h with the pilot onboard. The last line cleared at 1400 h and the ~3.5 day voyage to proposed Site AMDH-02A began at 1406 h. Throughout the day, the scientists held introductory meetings on microbiology and fluid sampling, rock geochemistry, the operation of physical properties and paleomagnetic instrumentation, and core description.


Daily Science Report for 14 April 2023

Location: Dock 12, NATO Berth, Ponta Delgada, Azores, Portugal

Science Update: All shipboard personnel were tested for COVID-19. Two quarantined individuals tested positive. The last two oncoming JRSO members boarded the ship in the late morning. All scientists attended a full day of introductory meetings and presentations including Expedition 399 project overview, science objectives for the first site, the Captain’s introduction, a life at sea review, hazard communications instructions, outreach plans, and shipboard IT information. The expected time of departure from Ponta Delgada is 1300 h on 15 April.


Daily Science Report for 13 April 2023

Location: Dock 12, NATO Berth, Ponta Delgada, Azores, Portugal

Science Update: Oncoming Siem Offshore crew and JRSO staff were tested for COVID-19, boarded the JOIDES Resolution (JR), and conducted crossover meetings with their offgoing counterparts until 1400 h, when the latter departed the ship. Two oncoming JRSO members did not make the day’s transfer to the ship. The Expedition 399 scientists boarded the ship as well and were assisted by JRSO staff with their check-in before enjoying their first lunch aboard the JR. The scientists met at 1300 h for a general welcome and introductions. At 1400 h, the scientists watched a ship safety video and were subsequently given laboratory safety tours by JRSO staff. A shipment of laboratory storage bottles was received on the ship. One individual tested positive for COVID and was quarantined on the ship. The COVID-19 Mitigation Protocols Established for Safe JR Operations (COPE) are being followed.


Daily Science Report for 12 April 2023

Location: Dock 12, NATO Berth, Ponta Delgada, Azores, Portugal

Science Update: IODP Expedition 399, Building Blocks of Life, Atlantis Massif, officially began in Ponta Delgada, Portugal, at 0800 h on 12 April 2023 with the JOIDES Resolution tied up at Dock 12, NATO Berth. Port call activities for this port call are minimal because most of the activities occurred during the tie-up in Tarragona, Spain. At 1400 h the Schlumberger freight arrived, including the Ultrasonic Borehole Imager (UBI) and the flasked logging tools, and was loaded aboard. All oncoming scientists and JRSO staff were arriving, or had arrived, in Ponta Delgada and were staying in a hotel, scheduled to board the vessel on 13 April. All personnel received a COVID self-test kit to be used the following morning, before joining the group and boarding the bus to the ship.

Expedition 399 will be operating on the Atlantis Massif, an oceanic core complex at 30°N on the Mid-Atlantic Ridge. The massif is capped by a corrugated fault zone and is composed of a large gabbro intrusion into serpentinized mantle rocks to the south. These altered mantle rocks host the Lost City hydrothermal field, which is famous for carbonate chimneys the height of a house, venting alkaline fluids rich in hydrogen and methane. The hydrogen is formed by the reaction between seawater and the mantle mineral olivine and is a powerful source of energy that may have fueled the formation of the first building blocks of life on Earth. Before life could begin, small organic molecules must have formed abiotically. We will sample fluids in the borehole to look at active exchange of chemical components between fluid and rock and production of hydrogen and methane. We will also drill a shallow section expected to represent the subseafloor environments that reflect the processes leading to this remarkable system. Other aims of the expedition are to study the processes of formation of the Atlantis Massif, including magmatism, deformation, and high temperature seawater-rock interaction, as well as the microbes living within the rocks and in the borehole waters.