Sedimentation rates test models of oceanic detachment faulting. Issue 20 (23rd October 2014)

• Record Type: Journal Article
• Authors: Parnell‐Turner, Ross; Cann, Johnson R.; Smith, Deborah K.; Schouten, Hans; Yoerger, Dana; Palmiotto, Camilla; Zheleznov, Alexei; Bai, Hailong
• Is Part Of: Geophysical research letters. Volume 41:Issue 20(2014:Oct.)
• Page Start: 7080
• Page End: 7088
• Publication Date: 2014-10-23
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2014GL061555
• Languages: English
• ISSNs: 0094-8276

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Long‐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.</p> </abstract>