DOI: 10.1016/j.epsl.2018.06.034
Scopus记录号: 2-s2.0-85049448294
论文题名: Genesis of corrugated fault surfaces by strain localization recorded at oceanic detachments
作者: Parnell-Turner R. ; Escartín J. ; Olive J.-A. ; Smith D.K. ; Petersen S.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 498 起始页码: 116
结束页码: 128
语种: 英语
英文关键词: corrugations
; mid-ocean ridge
; oceanic detachment faulting
Scopus关键词: Bathymetry
; Continuous casting
; Hydrographic surveys
; corrugations
; Deformation history
; Detachment faulting
; Mid-ocean ridges
; Oceanic core-complexes
; Oceanic detachment faults
; Strain localizations
; Systematic variation
; Faulting
; deformation
; detachment fault
; fault plane
; faulting
; mid-ocean ridge
; oceanic crust
; seafloor spreading
; strain analysis
; tectonic setting
; Atlantic Ocean
; Mid-Atlantic Ridge
英文摘要: Seafloor spreading at slow and ultraslow rates is often taken up by extension on large-offset faults called detachments, which exhume lower crustal and mantle rocks, and in some cases make up domed oceanic core complexes. The exposed footwall may reveal a characteristic pattern of spreading-parallel corrugations, the largest of which are clearly visible in multibeam bathymetric data, and whose nature and origin have been the subject of controversy. In order to tackle this debate, we use available near-bottom bathymetric surveys recently acquired with autonomous deep-sea vehicles over five corrugated detachments along the Mid-Atlantic Ridge. With a spatial resolution of 2 m, these data allow us to compare the geometry of corrugations on oceanic detachments that are characterized by differing fault zone lithologies, and accommodate varying amounts of slip. The fault surfaces host corrugations with wavelengths of 10–250 m, while individual corrugations are finite in length, typically 100–500 m. Power spectra of profiles calculated across the corrugated fault surfaces reveal a common level of roughness, and indicate that the fault surfaces are not fractal. Since systematic variation in roughness with fault offset is not evident, we propose that portions of the exposed footwalls analyzed here record constant brittle strain. We assess three competing hypotheses for corrugation formation and find that the continuous casting and varying depth to brittle–ductile transition models cannot explain the observed corrugation geometry nor available geological observations. We suggest a model involving brittle strain localization on a network of linked fractures within a zone of finite thickness is a better explanation for the observations. This model explains corrugations on oceanic detachment faults exposed at the seafloor and on normal faults in the continents, and is consistent with recently imaged corrugations on a subduction zone megathrust. Hence fracture linkage and coalescence may give rise to corrugated fault zones, regardless of earlier deformation history and tectonic setting. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109730
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States; CNRS/Institut de Physique du Globe de Paris, 1 rue Jussieu, Paris, 75005, France; Laboratoire de Géologie, Ecole Normale Supérieure/CNRS UMR 8538, PSL Research University, 24 rue Lhomond, Paris, 75005, France; National Science Foundation, 2415 Eisenhower Ave, Alexandria, VA 22314, United States; GEOMAR/Helmholtz Centre for Ocean Research, Wischhofstrasse 1-3, Kiel, 24148, Germany
Recommended Citation:
Parnell-Turner R.,Escartín J.,Olive J.-A.,et al. Genesis of corrugated fault surfaces by strain localization recorded at oceanic detachments[J]. Earth and Planetary Science Letters,2018-01-01,498