DOI: 10.1002/2013GL058729
论文题名: Seismic structure of the north-central Chilean convergent margin: Subduction erosion of a paleomagmatic arc
作者: Contreras-Reyes E. ; Becerra J. ; Kopp H. ; Reichert C. ; Díaz-Naveas J.
刊名: Geophysical Research Letters
ISSN: 0094-10294
EISSN: 1944-10025
出版年: 2014
卷: 41, 期: 5 起始页码: 1523
结束页码: 1529
语种: 英语
英文关键词: Chile
; gravitational collapse
; hydrofracturing
; subduction
; subduction erosion
Scopus关键词: Bathymetry
; Buildings
; Gravitational effects
; Seismic waves
; Seismology
; Stars
; Structural geology
; Velocity
; Chile
; Gravitational collapse
; Hydro-fracturing
; subduction
; Subduction erosion
; Erosion
; bathymetry
; continental crust
; continental slope
; convergent margin
; cordillera
; crustal thinning
; discontinuity
; forearc basin
; listric fault
; paleomagnetism
; seismic data
; seismic reflection
; seismic refraction
; seismic tomography
; seismic velocity
; subduction
; subsidence
; Chile
英文摘要: We study the erosive convergent margin of north-central Chile (at ~31°S) by using high-resolution bathymetric, wide-angle refraction, and multichannel seismic reflection data to derive a detailed tomographic 2-D velocity-depth model. In the overriding plate, our velocity model shows that the lowermost crustal velocities beneath the upper continental slope are 6.0-6.5 km/s, which are interpreted as the continental basement composed by characteristic metamorphic and igneous rocks of the Coastal Cordillera. Beneath the lower and middle continental slope, however, the presence of a zone of reduced velocities (3.5-5.0 km/s) is interpreted as the outermost fore arc composed of volcanic rocks hydrofractured as a result of frontal and basal erosion. At the landward edge of the outermost fore arc, the bathymetric and seismic data provide evidence for the presence of a prominent trenchward dipping normal scarp (~1 km offset), which overlies a strong lateral velocity contrast from ~5.0 to ~6.0 km/s. This pronounced velocity contrast propagates deep into the continental crust, and it resembles a major normal listric fault. We interpret this seismic discontinuity as the volcanic-continental basement contact of the submerged Coastal Cordillera characterized by a gravitational collapse of the outermost fore arc. Subduction erosion has, most likely, caused large-scale crustal thinning and long-term subsidence of the outermost fore arc. Key Points Our results have implications for subduction erosion A major velocity discontinuity is detected beneath the middle continental slope Possible gravitational collapse of the outermost fore-arc block off north Chile ©2014. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84895777265&doi=10.1002%2f2013GL058729&partnerID=40&md5=02487711aa4449c2343b48b07586f22b
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/7558
Appears in Collections: 气候减缓与适应
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作者单位: Departamento de Geofísica, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile
Recommended Citation:
Contreras-Reyes E.,Becerra J.,Kopp H.,et al. Seismic structure of the north-central Chilean convergent margin: Subduction erosion of a paleomagmatic arc[J]. Geophysical Research Letters,2014-01-01,41(5).