DOI: 10.1016/j.epsl.2018.02.009
Scopus记录号: 2-s2.0-85044350974
论文题名: Rayleigh and S wave tomography constraints on subduction termination and lithospheric foundering in central California
作者: Jiang C. ; Schmandt B. ; Hansen S.M. ; Dougherty S.L. ; Clayton R.W. ; Farrell J. ; Lin F.-C.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 488 起始页码: 14
结束页码: 26
语种: 英语
英文关键词: Isabella Anomaly
; lithospheric foundering
; Monterey microplate
; San Andreas Fault
; Sierra Nevada
Scopus关键词: Seismology
; Shear flow
; Shear waves
; Strike-slip faults
; Tomography
; Velocity
; Isabella Anomaly
; Lithospheric
; Microplates
; San Andreas fault
; Sierra Nevada
; Structural geology
; lithosphere
; microplate
; Rayleigh wave
; S-wave
; San Andreas Fault
; seismic tomography
; seismic velocity
; subduction
; upper mantle
; California
; Sierra Nevada [California]
; United States
英文摘要: The crust and upper mantle structure of central California have been modified by subduction termination, growth of the San Andreas plate boundary fault system, and small-scale upper mantle convection since the early Miocene. Here we investigate the contributions of these processes to the creation of the Isabella Anomaly, which is a high seismic velocity volume in the upper mantle. There are two types of hypotheses for its origin. One is that it is the foundered mafic lower crust and mantle lithosphere of the southern Sierra Nevada batholith. The alternative suggests that it is a fossil slab connected to the Monterey microplate. A dense broadband seismic transect was deployed from the coast to the western Sierra Nevada to fill in the least sampled areas above the Isabella Anomaly, and regional-scale Rayleigh and S wave tomography are used to evaluate the two hypotheses. New shear velocity (Vs) tomography images a high-velocity anomaly beneath coastal California that is sub-horizontal at depths of ∼40–80 km. East of the San Andreas Fault a continuous extension of the high-velocity anomaly dips east and is located beneath the Sierra Nevada at ∼150–200 km depth. The western position of the Isabella Anomaly in the uppermost mantle is inconsistent with earlier interpretations that the Isabella Anomaly is connected to actively foundering foothills lower crust. Based on the new Vs images, we interpret that the Isabella Anomaly is not the dense destabilized root of the Sierra Nevada, but rather a remnant of Miocene subduction termination that is translating north beneath the central San Andreas Fault. Our results support the occurrence of localized lithospheric foundering beneath the high elevation eastern Sierra Nevada, where we find a lower crustal low Vs layer consistent with a small amount of partial melt. The high elevations relative to crust thickness and lower crustal low Vs zone are consistent with geological inferences that lithospheric foundering drove uplift and a ∼3–4 Ma pulse of basaltic magmatism. © 2018 Elsevier B.V.
Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109988
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
There are no files associated with this item.
作者单位: Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, United States; Earthquake Science Center, U.S. Geological Survey, Pasadena, CA 91106, United States; Seismological Laboratory, California Institute of Technology, Caltech, 252-21, Pasadena, CA 91125, United States; Department of Geology and Geophysics, The University of Utah, Salt Lake City, UT 84112, United States
Recommended Citation:
Jiang C.,Schmandt B.,Hansen S.M.,et al. Rayleigh and S wave tomography constraints on subduction termination and lithospheric foundering in central California[J]. Earth and Planetary Science Letters,2018-01-01,488