Ross Sea West Antarctic Ice Sheet History, 2019

Contents 1 Background and objectives 2 Operations 4 Lithostratigraphy 10 Biostratigraphy and paleontology 16 Paleomagnetism 20 Physical properties 26 Geochemistry and microbiology 29 References

Proceedings of the IODP, 2014

Proceedings of the International Ocean Discovery Program, 2017

Proceedings of the International Ocean Discovery Program, 2016

4 Background and objectives 6 Operations 11 Lithostratigraphy 30 Biostratigraphy 31 Paleomagnetism 36 Geochemistry and microbiology 41 Physical properties 47 Downhole measurements 47 Stratigraphic synthesis 54 References C. France-Lanord et al. Site U1451 IODP Proceedings 3 V o l u m e 3 5 4 Calcareous nannofossils and foraminiferal biostratigraphic analyses at Site U1451 resulted in the identification of 39 biomarkers and the construction of 31 biozones, providing a comprehensive and detailed age model for the long-term development of the Middle Bengal Fan from the Paleogene to recent. Furthermore, the transition from pelagic-dominated sedimentation to probably Himalayan-derived turbiditic sediments is constrained near the Oligocene/Miocene boundary. The uppermost 120 m of Hole U1451A (lithostratigraphic Units I-III) is a sequence of turbiditic sands and muds with minor intercalated hemipelagic layers. Six biomarkers were identified within this sequence, providing good age control for Pleistocene fan development at this site. A thick (66 m) pelagic sequence was recovered in Cores 23F-29F (lithostratigraphic Unit IV) and contains eight biomarkers. This sequence represents more than 3 My of pelagic sedimentation, with little turbiditic influence. Below lithostratigraphic Unit IV, 450 m of turbidite-dominated sedimentation, present from Core 30F to the base of the hole, was deposited in approximately 3.5 My, based on four biomarkers observed in this sequence. The accumulation rates of ~1 and >10 cm/ky in the pelagic sequence and the turbidite-dominated sequence, respectively, suggest that the majority of turbiditic activity at this position occurred in the Miocene and Pleistocene and is more restricted in the Pliocene. The first occurrence of Catinaster coalitus was observed at the base of Hole U1451A (midpoint = 575.60 m CSF-A) and the top of Hole U1451B (590.06 m CSF-A) and provides tight age control for the overlap succession of the two holes. The Oligocene/Miocene boundary was recovered and lies between Samples 354-U1451B-54R-CC and 63R-CC. This boundary is identified by the last occurrence (LO) of Reticulofenestra bisectus and Zygrhablithus bijugatus (nannofossil Zone NP25). A major change from turbidite-dominated to pelagic-dominated sedimentation occurs between Cores 62R and 63R (nannofossil Zone NP24). Because of intense recrystallization and preservation issues, the depositional age of the limestones is difficult to constrain. Samples 71R-CC and 72R-CC contain Morozovella aragonensis, which is a marker species for foraminifer Zone E9 (43.6-52.3 Ma). The radiolarian species Thyrsocyrtis rhizodon was observed in Sample 69R-CC, confirming an Eocene age for these sediments. There appears to be a significant hiatus of 16-18 My between Samples 71R-CC and 72R-CC. Sample 72R-1, 0-1 cm, contains Discoaster multiradiatus and Fasciculithus spp., which are biomarkers for nannofossil Zone NP10. Sample 73R-CC represents a gap zone marked by the absence of D. multiradiatus and places the base of Site U1451 in the Paleocene (Thanetian). Confirming the presence and extent of this hiatus will be the subject of postexpedition research. Paleomagnetism of 269 archive section halves and 93 discrete samples from Site U1451 allowed us to identify 12 polarity reversals in Hole U1451A, mostly in calcareous clay deposits. We place the boundary between the Brunhes and Matuyama Chrons at 72.24 m CSF-A in Hole U1451A. A calcareous ooze deposit in Hole U1451A contains polarity zones corresponding to the Jaramillo and Cobb Mountain .44 m CSF-A, respectively), allowing us to correlate the interval with similar lithostratigraphic units at Sites U1449 and U1450. Several reversals between 140 and 163 m CSF-A in Hole U1451A are interpreted as the Gauss and Gilbert Chrons and their subchrons. Reversals at

Proceedings of the IODP, 2014

Proceedings of the IODP, 2014

During Integrated Ocean Drilling Program (IODP) Expedition 338, a slope basin seaward of the megasplay was logged and cored at Site C0021. The slope basin, characterized in 3-D seismic data by stacked mass transport deposits (MTDs) , was drilled and sampled in IODP Hole C0018A during IODP Expedition 333 and logged during Expedition 338 (Figs. ) (Expedition 333 Scientists, 2012a) to establish the stratigraphy of a Quaternary mass-movement event and to sample the distal part of a thick MTD for analyzing its rheological behavior to constrain sliding dynamics and tsunamigenic potential. Site C0018 was drilled at a location where the MTD bodies wedge out and basal erosion is minimal. During Expedition 338, logging while drilling (LWD) and coring to 294 and 194.5 meters below seafloor (mbsf), respectively, were conducted at Site C0021 (proposed Site NTS-1C) as contingency operations. This site is located ~2 km northwest of Site C0018 at a more proximal site for the MTDs analyzed at Site C0018 (Figs. ). Therefore, LWD and coring at Site C0021 provided additional information on the nature, provenance, and kinematics of MTDs. By combining data from drilling and postexpedition laboratory experiments on samples from Sites C0021 and C0018 (see the "Site C0018" chapter [Strasser et al., 2014c]), we will improve our understanding of dynamics of submarine landslides as it relates to their tsunamigenic potential. Hole C0021B core processing and measurements were divided into two phases: shipboard and shore based. The lack of ship time to completely process Hole C0021B cores on board during Expedition 338 dictated that only whole-round examinations could be performed; all remaining sampling tasks and analyses were deferred to a shore-based sampling party at the Kochi Core Center (KCC). Selected personnel from the science party, with some shore-based researchers, met at KCC in Kochi, Japan, from 25 to 30 April 2013 to participate in the sampling party and complete the site chapter reports. The D/V Chikyu shifted from Hole C0018B, where LWD operations were just completed, and we prepared to run the LWD bot-

Initial Reports of the Deep Sea Drilling Project

Nature: Basalt and nanno chalk Inferred vertical velocity to basement: 1.9 km/sec Age of Oldest Sediment: Middle Miocene Basement: Middle Miocene (intercalated sediments) Principal Results: This site, in the Gulf of Aden south of the Sheba Ridge and 70 km north of the Somalia Coast, was drilled and cored continuously to a depth of 584 meters, and 424.9 meters of sediment were obtained. These are hemipelagic with sands at intervals in the upper 220 meters; the remainder is acoustically transparent, consisting of nanno clay and nanno ooze as follows: Pleistocene 0-102 meters; upper Pliocene 102-178 meters; lower Pliocene 178-254 meters; upper Miocene 254-482 meters; and middle Miocene 482-566.5 meters (base of sediments). Sediments intercalated with basement are middle Miocene. There is little evidence for sediments being baked above the basaltic basement.

Bulletin of the British Ornithologists' Club, 2017

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Initial Reports of the Deep Sea Drilling Project, 1970

The Shipboard Scientific Party 1 The location of this site, on Magnetic Anomaly 6 west of the Mid-Atlantic* Ridge crest, was assisted by a preliminary detailed survey of the region by R/V Vema. This positive magnetic anomaly has an age of about 21 million years in the hypothesized geomagnetic time scale. Coring of the upper Tertiary sediments and basement rock sampling were the major objectives at this site.

IETE Journal of Research, 2016