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Sedimentation rates test models of oceanic detachment faulting


Type

Article

Change log

Authors

Parnell‐Turner, Ross 
Cann, Johnson R 
Smith, Deborah K 
Schouten, Hans 
Yoerger, Dana 

Abstract

jats:titleAbstract</jats:title>jats:pLong‐lived detachment faults play an important role in the construction of new oceanic crust at slow‐spreading mid‐oceanic ridges. Although the corrugated surfaces of exposed low‐angle faults demonstrate past slip, it is difficult to determine whether a given fault is currently active. If inactive, it is unclear when slip ceased. This judgment is crucial for tectonic reconstructions where detachment faults are present, and for models of plate spreading. We quantify variation in sediment thickness over two corrugated surfaces near 16.5°N at the Mid‐Atlantic Ridge using near‐bottom Compressed High Intensity Radar Pulse (CHIRP) data. We show that the distribution of sediment and tectonic features at one detachment fault is consistent with slip occurring today. In contrast, another corrugated surface 20 km to the south shows a sediment distribution suggesting that slip ceased ~150,000 years ago. Data presented here provide new evidence for active detachment faulting, and suggest along‐axis variations in fault activity occur over tens of kilometers.</jats:p>

Description

This is the accepted manuscript version.The final version is available from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/2014GL061555/full.

Keywords

37 Earth Sciences, 3703 Geochemistry, 3705 Geology, 3706 Geophysics

Journal Title

Geophysical Research Letters

Conference Name

Journal ISSN

0094-8276
1944-8007

Volume Title

41

Publisher

American Geophysical Union (AGU)
Sponsorship
This work was supported by the National Science Foundation grant number OCE-1155650.