By Prof. Michael Strasser (Exp. 386 Co-chief Scientist)
IODP Expedition 386 reached two new depth records
in Scientific Ocean Drilling & Coring
• the deepest water site ever drilled and cored at the water depth of 8023 m
• the deepest sub-sea level sample at 8060.74 mbsl (meters below sea level)
Forty-three years ago the legendary Drilling Vessel Glomar Challenger set the record for the deepest coring site in 50 years of scientific ocean drilling, by recovering two 15.5 and 20.5 m long cores from 7034 and 7029 meter water depth in the Mariana Trench (DSDP Leg 60 Site 461). This record has stood for all this time, until in the early morning of Friday May 14 2021, Captain Naoto Kimura of the Research Vessel Kaimei positioned the vessel at IODP Expedition 386 Site M0081, where the water depth is 8023 m.
The crew prepared the 40 meter long Giant Piston Corer (GPC) and ran it into the water at 09:20 local time. At a winch speed of 1.1 m/s it took about 2 hours and 40 minutes to lower the GPC assembly to just above seafloor at this deepest water site of our Expedition, and which now breaks the record as the new deepest water site drilled and cored within scientific ocean drilling history. At 12:06 local time, spud in took place and the crew then pulled out and ran the assembly back to surface, where the GPC was recovered to deck at 15:00 local time.
Later, a total of 37.74-meters of sediment core was curated, setting another new scientific drilling depth record for the deepest sub-sea level sample at 8060.74 mbsl (meters below sea level) exceeding the previous deepest sub-sea level sample from Site C0019E (IODP Exp. 343: J-Fast in 2012; Water depth 6889.5 m; Subsurface penetration to 844.5 meters below sea floor; until now deepest subseafloor sample below sea level at 7734 mbsl). We greatly acknowledge the tremendous efforts of the Captain and his crew to safely carry out such challenging ultra-deep water coring operations and look forward to now undertaking scientific analyses on these samples from the deepest of the deep.