Sea-Level Fall Driving Enhanced Hydrothermal and Tectonic Activities: Evidence From a Sediment Core Near the Tectonic-Controlled Tianxiu Vent Field, Carlsberg Ridge

Hydrothermal activity on mid-ocean ridges plays an important role in shaping marine chemistry, yet the variability of hydrothermal venting and its forcing mechanism remain elusive. Here, we analyzed a sediment core obtained near the tectonic-controlled Tianxiu vent field, Carlsberg Ridge, to reconstruct the hydrothermal venting history. The core documented two significant hydrothermal events (H1 and H2) in the past 30 ka. H1 occurred at 24.1-24.5 ka during the Last Glacial Maximum (LGM), while H2 occurred at 10.5-11.6 ka during the deglacial period. Compared to H2, H1 was relatively weak, and it occurred concurrently with a tectonic event. We suggest that H2 was caused by the increased melt production associated with the decompression melting of the upper mantle during sea-level fall, which is consistent with previously published records, whereas H1 was likely triggered by an intense tectonic event associated with depressurization during the LGM, which was previously unrecognized.