DOI: 10.1002/grl.50375
论文题名: Constraints on the composition of the Aleutian arc lower crust from V P/VS
作者: Shillington D.J. ; Van Avendonk H.J.A. ; Behn M.D. ; Kelemen P.B. ; Jagoutz O.
刊名: Geophysical Research Letters
ISSN: 0094-8932
EISSN: 1944-8663
出版年: 2013
卷: 40, 期: 11 起始页码: 2579
结束页码: 2584
语种: 英语
英文关键词: island arc
; lower crust
; Vp/Vs
Scopus关键词: Aleutian Arc
; Arc magmatism
; Bulk compositions
; Competing models
; Crustal rocks
; Island arc
; Lower crust
; P-wave velocity
; Wave propagation
; Quartz
; island arc
; lower crust
; magmatism
; P-wave
; petrology
; refraction
; S-wave
; ultramafic rock
; wave velocity
; xenolith
; Aleutian Margin
; Pacific Ocean
英文摘要: Determining the bulk composition of island arc lower crust is essential for distinguishing between competing models for arc magmatism and assessing the stability of arc lower crust. We present new constraints on the composition of high P-wave velocity (VP = 7.3-7.6 km/s) lower crust of the Aleutian arc from best-fitting average lower crustal VP/VS ratio using sparse converted S-waves from an along-arc refraction profile. We find a low VP/VS of ∼1.7-1.75. Using petrologic modeling, we show that no single composition is likely to explain the combination of high VP and low VP/VS. Our preferred explanation is a combination of clinopyroxenite (∼50-70%) and alpha-quartz bearing gabbros (∼30-50%). This is consistent with Aleutian xenoliths and lower crustal rocks in obducted arcs, and implies that ∼30-40% of the full Aleutian crust comprises ultramafic cumulates. These results also suggest that small amounts of quartz can exert a strong influence on VP/VS in arc crust. © 2013 American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879916749&doi=10.1002%2fgrl.50375&partnerID=40&md5=f2abfb89b1d3694bcfbb0fb9a3e865d5
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/6196
Appears in Collections: 气候减缓与适应
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作者单位: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States
Recommended Citation:
Shillington D.J.,Van Avendonk H.J.A.,Behn M.D.,et al. Constraints on the composition of the Aleutian arc lower crust from V P/VS[J]. Geophysical Research Letters,2013-01-01,40(11).