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1. Data report: high-resolution digital imaging of whole-round hard rocks collected during IODP Expeditions 390C, 395E, 390, and 393, South Atlantic Transect, using a DMT CoreScan3

   https://doi.org/10.14379/iodp.proc.390393.209.2024  

    Grant, L.J.C.; Evans, A.D.; Coggon, R.M.; Estep, J.D.; McIntyre, A.; Slagle, A.; Widlansky, S.J.; Albers, E.; Harris, M.; Teagle; et al (May 2024, Proceedings of the International Ocean Discovery Program Expedition reports)

   Hard rock cores recovered during International Ocean Discovery Program South Atlantic Transect (SAT) Expeditions 390C, 395E, 390, and 393 were digitally imaged using a DMT CoreScan3 line scanner aboard the R/V JOIDES Resolution during Expeditions 390 and 393. Methods outlined here involve modification of the CoreScan3 to scan >1 m long sections of hard rock at a 40 pixel/mm resolution, four times higher resolution than previously achieved during an ocean drilling campaign. This method is combined with a dedicated Python package (StitchIT) written to compile multiple 20 cm frames into high-resolution core section images. Accompanying this report are all compiled high-resolution section images from the SAT, both as high-resolution individual images of each section and as moderate-resolution visual core description–style images. The methods outline best practices for digitally imaging external core surfaces, and the data set is the first to be generated specifically for emerging machine learning and computer vision applications. 

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2. Expedition 390 Preliminary Report: South Atlantic Transect 1

   https://doi.org/10.14379/iodp.pr.390.2022  

   Coggon, R.M.; Sylvan, J.B.; Teagle, D.A.H.; Reece, J.; Christeson, G.L.; Estes, E.R.; Williams, T.J. (October 2022, Preliminary report)

   The South Atlantic Transect (SAT) is a multidisciplinary scientific ocean drilling project that comprises four International Ocean Discovery Program (IODP) expeditions: engineering Expeditions 390C and 395E as well as Expeditions 390 and 393. Altogether, the expeditions aim to recover complete sedimentary sections and the upper 100–350 m of the underlying oceanic crust along a slow/intermediate spreading rate Mid-Atlantic Ridge crustal flow line at ~31°S. The sediments along this transect were originally spot cored more than 50 y ago during Deep Sea Drilling Project Leg 3 (December 1968–January 1969) to help verify the theories of seafloor spreading and plate tectonics. Given dramatic advances in drilling technology and analytical capabilities since Leg 3, many high-priority scientific objectives can be addressed by revisiting the transect. The SAT expeditions target six primary sites on 7, 15, 31, 49, and 61 Ma ocean crust, which fill critical gaps in our sampling of intact in situ ocean crust with regards to crustal age, spreading rate, and sediment thickness. Drilling these sites is required to investigate the history of the low-temperature hydrothermal interactions between the aging ocean crust and the evolving South Atlantic Ocean and quantify past hydrothermal contributions to global biogeochemical cycles. Samples from the transect of the previously unexplored sediment- and basalt-hosted deep biosphere beneath the South Atlantic Gyre are essential to refining global biomass estimates and examining microbial ecosystems’ responses to variable conditions in a low-energy gyre and aging ocean crust. The transect is located near World Ocean Circulation Experiment Line A10, providing access to records of carbonate chemistry and deepwater mass properties across the western South Atlantic through key Cenozoic intervals of elevated atmospheric CO2 and rapid climate change. Reconstruction of the history of the deep western boundary current and deepwater formation in the Atlantic basins will yield crucial data to test hypotheses regarding the role of evolving thermohaline circulation patterns in climate change and the effects of tectonic gateways and climate on ocean acidification. Engineering Expeditions 390C and 395E cored a single hole through the sediment/basement interface with the advanced piston corer/extended core barrel system at five of the six primary proposed SAT sites and installed a reentry system with casing either into basement or within 10 m of basement at each of those five sites. Expedition 390 (7 April–7 June 2022) conducted operations at three of the SAT sites, recovering 700 m of core (77% recovery) over 30.3 days of on-site operations. Sediment coring, basement drilling, and logging were conducted at two sites on 61 Ma crust, and sediment coring was completed at the 7 Ma crust site. At Site U1557 on 61 Ma crust, the drill bit was deposited on the seafloor prior to downhole logging, leaving Hole U1557D available for future deepening and to establish a legacy borehole for basement hydrothermal and microbiological experiments. Expedition 390 scientists additionally described, and analyzed data from, 792 m of core collected during Expeditions 390C and 395E. Expedition 393 plans to operate at four sites, conducting basement drilling and downhole logging at the 7 Ma site, in addition to sediment coring, basement drilling, and logging at the sites intermediate in age. 

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3. Expedition 390/393 methods

   Coggon, R.M.; Teagle, D.A.H.; Sylvan, J.B.; Reece, J.; Estes, E.R.; Williams, T.J.; Christeson, G.L.; Aizawa, M.; Albers, E.; Amadori, C.; et al (January 2024, Proceedings of the International Ocean Discovery Program Expedition reports)

   This section provides an overview of operations, depth conventions, core handling, curatorial procedures, and analyses performed on the R/V JOIDES Resolution during the International Ocean Discovery Program (IODP) South Atlantic Transect (SAT) Expeditions 390C, 395E, 390, and 393. This information applies only to shipboard work described in the Expedition reports section of the SAT Proceedings of the International Ocean Discovery Program volume. Methods used by investigators for shore-based analyses of expedition samples and data will be described in separate individual postexpedition research publications. 

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4. Expedition 395E Preliminary Report: Complete South Atlantic Transect Reentry Systems

   https://doi.org/10.14379/iodp.pr.395E.2021  

   Williams, T.; Estes, E.R.; Rhinehart, B.; Coggon, R.M.; Sylvan, J.B.; Christeson, G.L.; Teagle, D.A.H. (December 2021, Preliminary report)

   International Ocean Discovery Program (IODP) Expeditions 390C and 395E were implemented in response to the global COVID-19 pandemic and occupied sites proposed for the postponed Expeditions 390 and 393, South Atlantic Transect 1 and 2. Expedition 395E completed most of the preparatory work that Expedition 390C did not have time to complete. The overall objective of Expeditions 390C and 395E was to core one hole at each of the South Atlantic Transect sites with the advanced piston corer/extended core barrel (APC/XCB) system to basement for gas safety monitoring and to install a reentry system with casing through the sediment to a few meters into basement in a second hole. Expedition 395E started in Cape Town, South Africa, and ended in Reykjavík, Iceland, after 20 days of on-site operations. We cored to basement at two new sites, U1560 and U1561, and completed reentry systems at three sites, U1556, U1557, and U1560. These operations will expedite basement drilling during the rescheduled Expeditions 390 and 393. Hole U1560A (Proposed Site SATL-25A) lies in ~15.2 Ma crust and is composed of carbonate-rich sediments to 120 meters below seafloor (mbsf) and 2.5 m of underlying basalt. A reentry system was deployed in Hole U1560B to 122.0 mbsf. We then moved to the sites at the western end of the transect on ~61 Ma crust. In Hole U1557D, 10¾ inch casing was deployed to 571.6 mbsf to deepen the 16 inch casing that was deployed during Expedition 390C, and in Hole U1556B, a reentry system was deployed to 284.2 mbsf. The remaining operations time was insufficient to install a reentry system at the originally planned site, Proposed Site SATL-33B. Instead, we cored Hole U1561A (Proposed Site SATL-55A) to 47 mbsf. It is composed of red clay and carbonate ooze overlying 3 m of basalt. The six primary sites of the South Atlantic Transect lie perpendicular to the Mid-Atlantic Ridge on the South American plate, overlying crust ranging in age from 7 to 61 Ma. Basement coring will increase our understanding of how crustal alteration progresses over time across the flanks of a slow/intermediate-spreading ridge and how microorganisms survive in deep subsurface environments. Sediment will be used in paleoceanographic and microbiological studies. 

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5. Site U1558

   Teagle, D.A.H.; Reece, J.; Williams, T.J.; Coggon, R.M.; Sylvan, J.B.; Estes, E.R.; Christeson, G.L.; Albers, E.; Amadori, C.; Belgrano, T.M.; et al (January 2024, Proceedings of the International Ocean Discovery Program Expedition reports)

   Site U1558 (30°53.7814′S, 24°50.4822′W; proposed Site SATL-43A) is in the central South Atlantic Ocean at a water depth of ~4334 meters below sea level (mbsl) ~1067 km west of the Mid-Atlantic Ridge (see Figure F1 and Tables T1, T2, all in the Expedition 390/393 summary chapter [Coggon et al., 2024c]) on crust that formed at a slow half spreading rate of ~19.5 mm/y (Kardell et al., 2019; Christeson et al., 2020) (see Figure F7 in the Expedition 390/393 summary chapter [Coggon et al., 2024c]). With an estimated age of 49.2 Ma, Site U1558 is the second oldest location of the South Atlantic Transect (SAT) campaign (International Ocean Discovery Program [IODP] Expeditions 390C, 395E, 390, and 393). 

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