Enhanced East Pacific Rise hydrothermal activity during the last two glacial terminations

Area of Science:

• Earth Science
• Geology
• Oceanography

Background:

• Mid-ocean ridge magmatism results from seafloor spreading and mantle decompression melting.
• Melt production may be modulated by glacial-interglacial sea level changes, potentially linking magmatic flux to ice-sheet size.
• Previous studies lacked precise timing to connect ridge magmatism with Pleistocene climate shifts.

Purpose of the Study:

• To investigate the relationship between mid-ocean ridge magmatism and past climate change.
• To constrain the timing of melt variability in mid-ocean ridge systems.
• To explore the potential role of magmatic flux as a feedback mechanism in glacial cycles.

Main Methods:

• Analysis of well-dated sedimentary records from the East Pacific Rise.
• Reconstruction of past hydrothermal activity levels.
• Correlation of magmatic anomalies with glacial-interglacial periods.

Main Results:

• Sedimentary records reveal enhanced hydrothermal activity during the last two glacial terminations.
• Evidence suggests anomalous upper mantle melting occurred during glacial maxima when sea levels were lower.
• Magmatic anomalies at mid-ocean ridges coincided with periods of deglaciation.

Conclusions:

• Sea level fluctuations during glacial cycles influence upper mantle melting and mid-ocean ridge magmatism.
• Enhanced magmatism during deglaciation may have contributed to ice-sheet retreat through heat and carbon release.
• Mid-ocean ridge magmatism potentially acts as a negative feedback on ice-sheet size, influencing global climate transitions.