Kinematics of footwall exhumation at oceanic detachment faults: solid‐block rotation and apparent unbending

Authors: Dan SandifordSascha BruneAnne GlerumJohn NaliboffJoanne M. Whittaker

Uploaded by: Dan Sandiford

Upload date: August 28, 2023

Abstract

Seafloor spreading at slow rates can be accommodated on large-offset oceanic detachment faults (ODFs), that exhume lower crustal and mantle rocks in footwall domes termed oceanic core complexes (OCCs). Footwall rocks experience large rotation during exhumation, yet important aspects of the kinematics—particularly the relative roles of solid-block rotation and flexure—are not clearly understood. Using a high-resolution numerical model, we explore the exhumation kinematics in the footwall beneath an emergent ODF/OCC. A key feature of the models is that footwall motion is dominated by solid-block rotation, accommodated by the nonplanar, concave-down fault interface. A consequence is that curvature measured along the ODF is representative of a neutral stress configuration, rather than a “bent” one. Instead, it is in the subsequent process of “apparent unbending” that significant flexural stresses are developed in the model footwall. The brittle strain associated with apparent unbending is produced dominantly in extension, beneath the OCC, consistent with earthquake clustering observed in the Trans-Atlantic Geotraverse at the Mid-Atlantic Ridge.

Publication

DOI10.1029/2021gc009681
Sandiford, D., Brune, S., Glerum, A., Naliboff, J., & Whittaker, J. M. (2021). Kinematics of Footwall Exhumation at Oceanic Detachment faults: Solid‐Block Rotation and Apparent Unbending. Geochemistry, Geophysics, Geosystems, 22(4). DOI: 10.1029/2021gc009681

Tags

C++extensionmid-ocean ridgetectonics

Graphic abstract

Graphic abstract | Kinematics of footwall exhumation at oceanic detachment faults: solid‐block rotation and apparent unbending

Licence

CC BY 4.0 DEED Attribution 4.0 International

CC BY 4.0: CC BY 4.0 DEED Attribution 4.0 International