IODP Technical Note

Site U1559

“…At Site U1559, the characterization of physical properties of the 6.6 Ma ocean crustal section is primarily based on cores from Hole U1559B that were recovered during Expedition 393. The uppermost basement was also recovered from Hole U1559A during Expedition 390C and from Hole U1559D during Expedition 390 (see Sediment in Physical properties and downhole measurements; Estes et al, 2021). The basement sequence at Site U1559 consists of basalt and volcanic glass with minor amounts of sediment that all show evidence of hydrothermal alteration (see Igneous petrology and Alteration petrology).…”

“…nannoliths) (Figure F9). Hole U1559A was cored in November 2020 during Expedition 390C (see Background and objectives) (Estes et al, 2021) but was not described until May 2022 during Expedition 390. Therefore, some color differences between the digital color images and the visual color determinations by Munsell color classification might occur.…”

“…Site U1559 was first occupied during engineering Expedition 390C, during which Hole U1559A was cored using the advanced piston corer (APC) and extended core barrel (XCB) systems to a total depth of 66.2 meters below seafloor (mbsf ), penetrating the entire sediment succession and ~2 m into basement (see Table T2 in the Expedition 390/393 summary chapter [Coggon et al, 2024d]) (Estes et al, 2021). After operations in Hole U1559A were complete, a reentry system with 13⅜ inch casing was installed to 55.31 mbsf in Hole U1559B (Figure F4).…”

Expedition 390/393 methods

“…We used the contamination tracer PFMD for the SAT expeditions (Li et al, 2020;Sylvan et al, 2021) (Figure F37), following the methodology used during Expedition 360 (MacLeod et al, 2017). PFMD was continuously pumped with the drilling fluid at an average rate of ~0.5 mL/min; the pump rate was set to vary with drill fluid pump rate.…”

Expedition 399 Preliminary Report: Building Blocks of Life, Atlantis Massif

“…Insights into the constraints on life in the subseafloor and the metabolic strategies that the small numbers of inhabitants employ can be gained in part through characterization of the endolithic communities. Distinguishing endemic microbial taxa from those introduced from seawater or contamination is a major challenge requiring multiple strategies to overcome (Kallmeyer, 2017;Sylvan et al, 2021;Pendleton et al, 2021). Nonetheless, the signatures of endolithic communities have been successfully identified from the subseafloor of the Atlantis Massif during both Expeditions 304 (Mason et al, 2010) and 357 (Motamedi et al, 2020;Goordial et al, 2021;Quéméneur et al, 2019) (Figure F9).…”