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Article
Nonvolcanic Seafloor Spreading and Corner-Flow Rotation Accommodated by Extensional Faulting At 15 Degrees N on the Mid-Atlantic Ridge: A Structural Synthesis of ODP Leg 209
Geochemistry Geophysics Geosystems
  • T. Schroeder, University of Wyoming
  • H.J.B. Dick
  • U. Faul
  • J. F. Casey
  • P. B. Kelemen
Document Type
Article
Publication Date
6-28-2007
Disciplines
Abstract
[1] Drilling during ODP Leg 209, dredging, and submersible dives have delineated an anomalous stretch of the Mid-Atlantic Ridge north and south of the 15 degrees 20'N Fracture Zone. The seafloor here consists dominantly of mantle peridotite with gabbroic intrusions that in places is covered by a thin, discontinuous extrusive volcanic layer. Thick lithosphere ( 10 - 20 km) in this region inhibits magma from reaching shallow levels beneath the ridge axis, thereby causing plate accretion to be accommodated by extensional faulting rather than magmatism. The bathymetry and complex fault relations in the drill-core suggest that mantle denudation and spreading are accommodated by a combination of high-displacement, rolling-hinge normal faults and secondary lower-displacement normal faults. These extensional faults must also accommodate corner flow rotation ( up to 90 degrees) of the upwelling mantle within the shallow lithosphere, consistent with remnant magnetic inclinations in denuded peridotite and gabbro from Leg 209 core that indicate up to 90 degrees of sub-Curie-temperature rotation.
DOI
10.1029/2006GC001567
Comments

An edited version of this paper was published by AGU. Copyright 2007 American Geophysical Union.

Citation Information
T. Schroeder, H.J.B. Dick, U. Faul, J. F. Casey, et al.. "Nonvolcanic Seafloor Spreading and Corner-Flow Rotation Accommodated by Extensional Faulting At 15 Degrees N on the Mid-Atlantic Ridge: A Structural Synthesis of ODP Leg 209" Geochemistry Geophysics Geosystems Vol. 8 (2007)
Available at: http://works.bepress.com/michael_cheadle/5/