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IODP Expedition 369

Australia Cretaceous Climate and Tectonics


Daily Science Report for 15 October 2017

Location: In transit to Site U1513 (proposed Site MBAS-4C)

Science Update: We are underway to our next site (proposed Site MBAS-4C). Please note the change in destination from yesterday; we are now headed to the alternate site for Site MBAS-4B. The decision to switch to the proposed alternate site was based on evidence from the seismic profiles that suggests the sedimentary section of Cretaceous age may be more expanded. We still anticipate arriving in the morning of 18 October.

The science party is finishing remaining Site U1512 analyses, as well as working on the Site U1512 reports and preparing for the site review meeting.


Daily Science Report for 14 October 2017

Location:
Hole U1512A (34°1.6406′S, 127°57.7605′E, 3071 m water depth)
In transit to Site U1513 (proposed Site MBAS-4B)

Science Update: We completed preparations for logging by 0430 h with the drill pipe pulled up to logging depth (~70 m). We were able to complete an entire log of the open borehole to depth (69.9 m to 698.8 m) with the modified triple combination tool string by 1130 h. After the successful logging run, we rigged down the logging tools and continued pulling the drill pipe out of the hole and back up to the rig floor. We completed operations at Site U1512 at 2255 h and began our transit to the next site (Site U1513, proposed Site MBAS-4B). We anticipate arriving in the morning of Wednesday 18 October.

The remaining cores from the hole were described. Cores U1512A-62R to 73R (585.6–701.38 m) consist of dark silty claystone with sandstone layers containing siderite. Calcium carbonate values for the dark silty claystone remain <1 wt%. Fragments of inoceramid shells and agglutinated foraminifera are present and planktonic foraminifera are absent. Calcareous nannofossils are from Zone CC11, giving a Turonian age for the base of the hole.


Daily Science Report for 13 October 2017

Location: Hole U1512A (34°1.6406′S, 127°57.7605′E, 3071 m water depth)

Science Update: We retrieved Cores U1512A-64R to 73R from 604.8 to 700.8 m, recovering 90.56 m of material (94%). The recovery of Core 73R at 1915 h completed coring operations at Site U1512. Overall, we recovered 631.86 m of 700.8 m cored (90%) with the RCB system. After coring was completed, we began preparations for downhole logging, including a heavy mud sweep. As of midnight, we were pulling the drill pipe slowly up to logging depth (~70 m). The planned logging operations include one deployment of a modified triple combination tool string, as it will contain the sonic tool usually run with the FMS-sonic tool string. This configuration will provide us with information on natural gamma radiation, density, resistivity, and velocity.

Cores U1512A-52R to 61R (489.6–585.6 m) were described and consist of dark silty claystone. Calcium carbonate values for the dark silty claystone are <1 wt%. With the exception of Cores 52R and 56R, all cores contain at least one discrete siltstone or sandstone layer. Approximately half of the silt- and sandstone intervals contain siderite. Fragments of inoceramid shells are abundant and agglutinated foraminifera are present in most core catcher samples while planktonic foraminifera are absent. Calcareous nannofossils in this described interval all date to CC11 (Turonian, ~92 Ma).


Daily Science Report for 12 October 2017

Location: Hole U1512A (34°1.6406′S, 127°57.7605′E, 3071 m water depth)

Science Update: We retrieved Cores U1512A-51R to 63R from 480 to 604.8 m, recovering 117.98 m of material. Core recovery is phenomenal, averaging 95%.

Cores U1512A-41R to 51R (384–489.58 m) were described and consist of dark silty claystone with discrete siltstone or sandstone layers in Sections 42R-3, 43R-CC, 44R-2, 44R-4, 44R-5, 46R-CC, 48R-CC, 49R-6, 50R-3, and 51R-1. The sandstone layers in Cores 48R to 51R contain siderite. Fragments of inoceramid shells are abundant and agglutinated foraminifera are present in most core catcher samples. Calcareous nannofossils in Section 41R-CC are still from CC12 (Turonian, ~90 Ma); however, nannofossils from Section 51R-CC are dated to CC11 (Turonian, ~92 Ma). Planktonic foraminifera are rare, but when present, they concur with a Turonian age for the material. Small, dispersed methane hydrates still occur in these cores, and the methane concentrations from headspace analysis are elevated (>75,000 ppm). Overall, this site is also producing an excellent natural gamma radiation record that corresponds well with industry data of the basin. Additionally, it appears that there is cyclicity in the data that possibly reflects short eccentricity cycles, so there is a possibility to construct an orbitally-tuned age model for the Late Cretaceous at this site.


Daily Science Report for 11 October 2017

Location: Hole U1512A (34°1.6′S, 127°57.7′E, 3071 m water depth)

Science Update: We retrieved Cores U1512A-37R to 50R from 345.6 to 480 m, recovering 124.87 m. Core recovery with the RCB system is excellent, averaging 93%.

Cores U1512A-30R to 40R (278.4–384.4 m) were described and they consist of dark silty claystone. The discrete glauconitic sandstone layers have decreased in occurrence with only one observed in Section 32R-5 at 303 m. The material continues to be mostly barren of calcareous nannofossils and foraminifera, but there are calcareous nannofossils in the core catchers of Cores 38R and 39R (374 m) that date the material to CC12 (Turonian, ~90 Ma). Agglutinated foraminifers and shell fragments remain abundant. Small, dispersed methane hydrates are present from Core 34R, which corresponds to high methane content (>100,000 ppm) in the headspace samples.


Daily Science Report for 10 October 2017

Location: Hole U1512A (34°1.6′S, 127°57.7′E, 3071 m water depth)

Science Update: We retrieved Cores U1512A-25R to 36R from 230.4 m to 345.6 m. Core recovery remains excellent (average of 88%) with 101.2 m recovered.

Cores 18R to 29R (163.2–277.8 m) were described and they consist of dark silty claystone. Discrete glauconitic sandstone layers (each about 10 cm thick) occur about once per core. There are also numerous burrows that are infilled with glauconitic sandstone. This material is barren of calcareous nannofossils and foraminfera, although there are abundant agglutinated foraminifers and shell fragments. Pore water geochemical profiles and increasing methane concentrations downhole suggest that we are below the sulfate–methane transition, which was likely around 100 m, and are in the methanogenesis (biogenic) zone.


Daily Science Report for 9 October 2017

Location: Hole U1512A (34°1.6′S, 127°57.7′E, 3071 m water depth)

Science Update: We retrieved Cores U1512A-14R to 24R from 134.4 to 230.4 m, recovering 96.3 m. Core recovery continues to be excellent at an average of 91%.

Cores U1512A-8R to 17R (~77–163 m) were described; Cores 8R and 9R are predominantly dark silty clay, and Cores 10R to 17R are dark claystone. There are two discrete sandstone layers (about 10 cm thick) in Sections 13R-5 and 17R-6; the latter contains glauconite. The base of Core 15R was dated to nannofossil zone CC15/16a (Santonian) and the few planktonic foraminifera present agree with a Late Cretaceous age. Below this core, the material is barren of calcareous nannofossils and foraminfera, although there are agglutinated foraminifers and abundant shell fragments.


Daily Science Report for 8 October 2017

Location: Hole U1512A (34°1.6′S, 127°57.7′E, 3071 m water depth)

Science Update: We continued RCB coring, and Cores U1512A-3R to 13R penetrated from 28.7 to 124.8 m and recovered 98.2 m. Core recovery has improved dramatically, averaging 93%.

Cores U1512A-1R to 7R were described. Core 1R to Section 2R-1 consists of foraminifer-rich nannofossil ooze that is Pleistocene in age. A sharp contact in Section 2R-1 marks a lithological change from ooze to dark silty clay. This clay is the dominant lithology in the subsequent cores and is likely Late Cretaceous in age. It contains biosiliceous material (radiolarians, diatoms, and sponge spicules), rare calcareous nannofossils, and extremely rare foraminifera, as well as abundant pyrite and some glauconite.


Daily Science Report for 7 October 2017

Location:
• Transit to Site U1512
• Hole U1512A (34°1.6′S, 127°57.7′E, 3070.87 m water depth)

Science Update: We arrived at Site U1512 (proposed Site WCED-4A) in the Great Australian Bight at 0530 h. The rig floor made preparations for rotary coring and we started Hole U1512A at 2120 h. We retrieved Cores U1512A-1R (7% recovery) and 2R (21% recovery) to 28.7 meters below sea floor (mbsf). Hole U1512A is the only hole planned at this site with a target depth of 570 mbsf; two wireline logging runs will be attempted after coring with the triple combination and Formation MicroScanner (FMS)-sonic tool strings.

Before the first core arrived on deck at 2240 h, the science party attended a science seminar from one of the geochemists on Cenomanian/Turonian Oceanic Anoxic Event 2 from southern high-latitude Pacific sites. They also finalized all preparations in the laboratories.


Daily Science Report for 6 October 2017

Location: In transit to Site U1512 (proposed Site WCED-4A)

Science Update: We are underway to our first site (Site U1512) in the Great Australian Bight with an estimated time of arrival of 0600 h on 7 October. The remaining half of the science party were given full ship tours by the Operations Superintendent and members of the ship’s crew. The science party also completed their laboratory setup with safety training on the handheld X-ray fluorescence device by the X-ray Laboratory technician. The Co-Chief Scientists and Expedition Project Manager began reviews of the laboratory groups’ Methods section drafts. The second of several planned science seminars was given by one of the Stratigraphic Correlators on reconstructing water masses and circulation with neodymium isotopes.


Daily Science Report for 5 October 2017

Location: In transit to Site U1512 (proposed Site WCED-4A)

Science Update: We are underway to our first site (Site U1512) in the Great Australian Bight. After averaging almost 12 kt, our estimated time of arrival is now 0600 h on 7 October. Approximately half of the science party were given full ship tours by the Operations Superintendent and members of the ship’s crew. The science party also finalized their laboratory setup and their Methods sections. The first of several planned science seminars was given by one of the Co-chief Scientists on seismic oceanography.


Daily Science Report for 4 October 2017

Location: In transit to Site U1512 (proposed site WCED-4A)

Science Update: After arriving at the Portland, Victoria, Australia pilot station to allow a crew member to depart at 1245 h, we continued on our transit to the first site (Site U1512) in the Great Australian Bight. Our estimated time of arrival is 1100 h on 7 October. The scientists on the night shift received a core flow tour from the technical staff. The science party continued laboratory setup and orientation and are finalizing their Methods sections. The Sample Allocation Committee held meetings with the laboratory groups to finalize the sampling plan for shipboard analyses.


Daily Science Report for 3 October 2017

Location: In transit to Site U1512 (proposed Site WCED-4A)

Science Update: We are underway to our first site (Site U1512) in the Great Australian Bight. At 1815 h, we changed course towards shore to allow a crew member to depart the ship on 4 October, after which we will continue onwards to the site. The scientists on the day shift (noon to midnight) received a core flow tour from the technical staff, which will be repeated for the opposite shift. The science party continued laboratory setup and orientation, as well as working on their Methods sections.


Daily Science Report for 2 October 2017

Location: In transit to Site U1512 (proposed Site WCED-4A)

Science Update: We are underway to our first site (Site U1512) in the Great Australian Bight. The weather and sea state improved and we are now averaging ~9 kt with an estimated arrival of 1300 h on 6 October. The science party are continuing work in their laboratory groups on their Methods sections and preparations for arrival on site.


Daily Science Report for 1 October 2017

Location:
• Macquarie Wharf, Berth 4, Hobart, Australia
• In transit to Site U1512 (proposed Primary Site WCED-4A)

Science Update: The loading of all freight was completed and final port call activities came to a close. We departed Hobart at 0710 h and began the transit to our first site (Site U1512; proposed Site WCED-4A) in the Great Australian Bight. We averaged less than 5 kt for the first ~16 h of the transit due to weather conditions. The first boat drill was conducted at 1300 h.

The science party have been working in their laboratory groups on their Methods sections and preparing for arrival at our first site. We anticipate arriving on site during the afternoon of 6 October.


Daily Science Report for 30 September 2017

Location: Macquarie Wharf, Berth 4, Hobart, Australia

Science Update: The science party received introductions to IODP publications from the Publications Specialist, as well as their obligations during the expedition and afterwards. They also received an introduction to coring operations from the Operations Superintendent.

Due to weather conditions, our estimated departure was revised to 0700 h on 1 October.


Daily Science Report for 29 September 2017

Location: Macquarie Wharf, Berth 4, Hobart, Australia

Science Update: The science party discussed their personal research interests. They then broke into their laboratory groups and began work in their laboratories with the respective laboratory specialists. During this time, the Sample Allocation Committee met with smaller groups to discuss personal research goals. The Co-Chief Scientists, Staff Scientist, Operations Superintendent, and Logging Scientists met with the Schlumberger Engineer and IODP Underway Geophysics Laboratory Specialist to discuss the logging tools and program; the Logging Scientists were also shown the logging tools. The Co-Chief Scientists, Staff Scientist, Operations Superintendent, and Stratigraphic Correlators also met with members of the drilling crew.

We are currently scheduled to leave Hobart early with an estimated departure of 1600 h on 30 September.


Daily Science Report for 28 September 2017

Location: Macquarie Wharf, Berth 4, Hobart, Australia

Science Update: The Co-Chief Scientists gave an introduction on the expedition science, which was followed by a practical presentation by the Staff Scientist about expedition reports and tasks. The science party received introductions to laboratory safety and were taken on laboratory safety tours, as well as a shipboard safety induction by the Captain, Navigational Officer, and Doctor.


Daily Science Report for 27 September 2017

Location: Macquarie Wharf, Berth 4, Hobart, Australia

Science Update: All members of the science party arrived and settled into their cabins, after which we began orientation activities and expedition preparation. This included getting set up on the network and tips for living at sea. We also continued our port call activities, including the ship’s crew change and loading of freight.


Daily Science Report for 26 September 2017

Location: Macquarie Wharf, Berth 4, Hobart, Australia

Science Update: IODP Australia Cretaceous Climate and Tectonics Expedition 369 officially began at 0930 h. JRSO Technical Staff, the Expedition Project Manager, and Co-Chief Scientists boarded the vessel and began port call activities, including IODP JRSO crew change and crossover and Co-Chief orientations. Scientists are scheduled to board the ship tomorrow (27 September).