Glacial cycles drive variations in the production of oceanic crust

TL;DR

This study demonstrates that glacial cycles influence oceanic crust production by causing pressure-driven variations in mantle melting, which are recorded in bathymetric features like abyssal hills, supported by theoretical models and new bathymetric data.

Contribution

The paper introduces a combined modeling and observational approach linking glacial cycles to variations in oceanic crust production and bathymetric features.

Findings

Spectral energy in bathymetry aligns with Milankovitch periods.

Model predicts crustal thickness variations of hundreds of meters.

Bathymetric features record mantle response to sea level changes.

Abstract

Glacial cycles redistribute water between oceans and continents causing pressure changes in the upper mantle, with consequences for melting of Earth's interior. Using Plio-Pleistocene sea-level variations as a forcing function, theoretical models of mid-ocean ridge dynamics that include melt transport predict temporal variations in crustal thickness of hundreds of meters. New bathymetry from the Australian-Antarctic ridge shows significant spectral energy near the Milankovitch periods of 23, 41, and 100 ky, consistent with model predictions. These results suggest that abyssal hills, one of the most common bathymetric features on Earth, record the magmatic response to changes in sea level. The models and data support a link between glacial cycles at the surface and mantle melting at depth, recorded in the bathymetric fabric of the sea floor.