Controls on the seafloor exposure of detachment fault surfaces

While oceanic detachment faults have been proposed to account for the accretion of ∼40% of new seafloor in the North Atlantic ocean, clear exposures of large-offset, often-corrugated fault surfaces remain scarce and spatially limited. To help resolve this paradox, we examine the conditions under whi...

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Bibliographic Details
Published in:Earth and planetary science letters 2019-01, Vol.506, p.381-387
Main Authors: Olive, Jean-Arthur, Parnell-Turner, Ross, Escartín, Javier, Smith, Deborah K., Petersen, Sven
Format: Article
Language:English
Subjects:
critical taper
detachment faulting
Earth Sciences
fault friction
mid-ocean ridge
oceanic core complex
Sciences of the Universe
Tectonics
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Summary:While oceanic detachment faults have been proposed to account for the accretion of ∼40% of new seafloor in the North Atlantic ocean, clear exposures of large-offset, often-corrugated fault surfaces remain scarce and spatially limited. To help resolve this paradox, we examine the conditions under which detachment fault growth may or may not lead to extensive exposure of corrugated fault planes at the seafloor. Using high-resolution bathymetry from four detachment faults at the northern Mid-Atlantic Ridge, we investigate the rafting of hanging wall-derived debris over emerging fault scarps, which can lead to covering shallow-dipping corrugated fault surfaces. We model this process using critical taper theory, and infer low effective friction coefficients (∼0.2) on the shallowest portion of detachment faults. A corollary to this result is that detachments emerging from the seafloor at angles
ISSN:0012-821X
1385-013X
DOI:10.1016/j.epsl.2018.11.001