Sedimentation rates test models of oceanic detachment faulting
Cann, Johnson R.
Smith, Deborah K.
Schouten, Hans A.
Yoerger, Dana R.
MetadataShow full item record
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.
Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 41 (2014): 7080–7088, doi:10.1002/2014GL061555.
Showing items related by title, author, creator and subject.
Fault rotation and core complex formation : significant processes in seafloor formation at slow-spreading mid-ocean ridges (Mid-Atlantic Ridge, 13°–15°N) Smith, Deborah K.; Escartin, Javier E.; Schouten, Hans A.; Cann, Johnson R. (American Geophysical Union, 2008-03-05)The region of the Mid-Atlantic Ridge (MAR) between the Fifteen-Twenty and Marathon fracture zones displays the topographic characteristics of prevalent and vigorous tectonic extension. Normal faults show large amounts of ...
Mylonitic deformation at the Kane oceanic core complex : implications for the rheological behavior of oceanic detachment faults Hansen, Lars N.; Cheadle, Michael J.; John, Barbara E.; Swapp, Susan M.; Dick, Henry J. B.; Tucholke, Brian E.; Tivey, Maurice A. (John Wiley & Sons, 2013-08-28)The depth extent, strength, and composition of oceanic detachment faults remain poorly understood because the grade of deformation-related fabrics varies widely among sampled oceanic core complexes (OCCs). We address this ...
Small-scale structure of the Kane oceanic core complex, Mid-Atlantic Ridge 23°30′N, from waveform tomography of multichannel seismic data Canales, J. Pablo (American Geophysical Union, 2010-11-03)Frequency-domain waveform tomography applied to deep-sea multichannel seismic data collected across the Kane oceanic core complex (OCC) reveals the small-scale structure of this section of oceanic lithosphere formed at the ...