[S-CG42] Hard-Rock Drilling Science: Continental and Deep-Sea Drilling, and Ophiolite

[SCG42-04] An initial result of IODP Exp399 Building Blocks of Life: serpentinite and gabbro drilling in the Atlantis Massif, MAR 30 degree N.

*Natsue Abe^1,2, Toshio Nozaka³, Kristine Dickenson⁴, Jeremy Deans⁵, Andreq McCaig⁶, Susan Lang⁷, Peter Blum⁸, IODP Exp.399 Science Party⁸ (1.Japan Agency for Marine-Earth Science and Technology , 2.Graduate School of Natural Science& Technology, Kanazawa University, 3.Okayama University, 4.University of California, Santa Cruz, 5.University of Southern Mississippi, 6.University of Leeds, 7.Woods Hole Oceanographic Institution, 8.IODP, Texas A&M University)

Keywords:IODP, Exp.399, MAR Atlantis Massif, Serpentinite, Carbonization, Oceanic Core Complex

IODP Exp. 399 (April 12 - June 12, 2023) was aimed to address the formation process of the ocean core complex (hereafter OCC), to explore the reaction process between the ocean crust and upper mantle and seawater, abiological reactions between water and rock that may represent ancient systems that predate life on Earth, and to evaluate sub-seafloor The drilling was conducted to assess life activities under the seafloor. The Atlantis body, an OCC located at 30°N in the Mid-Atlantic Ridge, is a seafloor exposure of gabbro and serpentinized peridotite, a constituent of the lower oceanic crust to the uppermost mantle, and four IODP cruises (Exps. 304 305, 340T and 357) have been conducted.
Exp. 399 extended the existing Hole U1309D (to 1498 mbsf) to sample the gabbros and successfully sampled hot fluids from the borehole. At the serpentinite site in the southern part of the body, Hole U1601C, the fifth deepest hole (1267.8 mbsf) drilled in basement rock in the IODP, was successfully penetrated. Continuous data recovery, including temperature, density, porosity, and seismic velocity, was obtained from in-hole measurements, and fluid samples were collected from multiple depths in the hole.
This presentation will discuss the cruise results, focusing on the physical property measurement data obtained.