esting Solid Earth - Climate Connections and Generation of Crust at the Fast-Spreading Southeast Pacific Rise using time series, Cruise No. SO314, 13th August 2025 - 5th October 2025, Pepeete (French Polynesia) - Antofagasta (Chile), T-SECTOR SEPR

Résumé fourni par la source

Cruise SO314 took place at the Southeastern Pacific Rise (SEPR) in late summer of 2025 in the frame of the EU-funded ERC Synergy Project "T-SECTOR". Its main goal was to provide evidence for direct links between climate (continental ice sheets and sea level) and solid Earth processes (amount and composition of newly formed oceanic crust at mid ocean ridges). Models have predicted that differences in hydrostatic pressure on the ocean crust as a consequence of glacial/interglacial sea level variability resulted in thicker newly formed oceanic crust, changes in its geochemical signature and elevated hydrothermal activity during glacials and vice versa. To achieve the goals of the cruise, 77 closely spaced gravity cores were taken along a 75 nm section across the SEPR, of which 44 reached the basaltic basement and contain basaltic glasses and hydrothermally influenced sediments in their lowermost meter directly above the basement. These cores reflect changes in the elemental and isotopic composition of the crust over time. They will form a continuous composite time series of volcanic and hydrothermal activity of the SEPR of the past 1 million years. Sampling was complemented by wax coring and dredging in areas without significant sediment coverage. To determine changes in crustal thickness over time, seismic measurements were carried out at highest resolution consisting of the multi-day deployment of Ocean Bottom Seismometers (3 x 47 OBS) and subsequent multi-channel seismic and refraction seismic profiling along the same 75 nm section as occupied for the sediment coring.

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