Tectonic evolution of 200 km of Mid-Atlantic Ridge over 10 million years : interplay of volcanism and faulting
Cann, Johnson R.
Smith, Deborah K.
Escartin, Javier E.
Schouten, Hans A.
MetadataShow full item record
We reconstruct the history of the mode of accretion of an area of the Mid-Atlantic Ridge south of the Kane fracture zone using bathymetric morphology. The area includes 200 km of the spreading axis and reaches to 10 Ma on either side. We distinguish three tectonic styles: (1) volcanic construction with eruption and intrusion of magma coupled with minor faulting, (2) extended terrain with abundant large-offset faults, (3) detachment faulting marked by extension on single long-lived faults. Over 40% of the seafloor is made of extended terrain and detachment faults. The area includes products of seven spreading segments. The spreading axis has had detachment faulting or extended terrain on one or both sides for 70% of the last 10 Ma. In some parts of the area, regions of detachment faulting and extended terrain lie close to segment boundaries. Regions of detachment faulting initiated at 10 Ma close to the adjacent fracture zones to the north and south, and then expanded away from them. We discuss the complex evidence from gravity, seismic surveys, and bathymetry for the role of magma supply in generating tectonic style. Overall, we conclude that input of magma at the spreading axis has a general control on the development of detachment faulting, but the relationship is not strong. Other factors may include a positive feedback that stabilizes detachment faulting at the expense of volcanic extension, perhaps through the lubrication of active detachment faults by the formation of low friction materials (talc, serpentine) on detachment fault surfaces.
Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 16 (2015): 2303-2321, doi:10.1002/2015GC005797.
Suggested CitationGeochemistry, Geophysics, Geosystems 16 (2015): 2303-2321
Showing items related by title, author, creator and subject.
Karson, Jeffrey A.; Fruh-Green, Gretchen L.; Kelley, Deborah S.; Williams, E. A.; Yoerger, Dana R.; Jakuba, Michael V. (American Geophysical Union, 2006-06-21)Near-bottom investigations of the cross section of the Atlantis Massif exposed in a major tectonic escarpment provide an unprecedented view of the internal structure of the footwall domain of this oceanic core complex. ...
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 ...
Crustal structure of the Trans-Atlantic Geotraverse (TAG) segment (Mid-Atlantic Ridge, 26°10′N) : implications for the nature of hydrothermal circulation and detachment faulting at slow spreading ridges Canales, J. Pablo; Sohn, Robert A.; deMartin, Brian J. (American Geophysical Union, 2007-08-09)New seismic refraction data reveal that hydrothermal circulation at the Trans-Atlantic Geotraverse (TAG) hydrothermal field on the Mid-Atlantic Ridge at 26°10′N is not driven by energy extracted from shallow or mid-crustal ...