DOI: 10.1007/s00531-013-0925-1
Scopus记录号: 2-s2.0-84902511078
论文题名: Highly depleted isotopic compositions evident in Iapetus and Rheic Ocean basalts: Implications for crustal generation and preservation
作者: Murphy J.B. ; Waldron J.W.F. ; Schofield D.I. ; Barry T.L. ; Band A.R.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2014
卷: 103, 期: 5 起始页码: 1219
结束页码: 1232
语种: 英语
英文关键词: Depleted mantle
; Iapetus Ocean
; Ophiolite
; Rheic Ocean
; Sm-Nd isotopes
Scopus关键词: Caledonian orogeny
; Caribbean plate
; crustal evolution
; Hercynian orogeny
; Iapetus Ocean
; isotopic composition
; mafic rock
; magmatism
; mantle structure
; ocean island basalt
; oceanic lithosphere
; ophiolite
; paleoceanography
; preservation
; spreading center
; subduction zone
; Atlantic Ocean
英文摘要: Subduction of both the Iapetus and Rheic oceans began relatively soon after their opening. Vestiges of both the Iapetan and Rheic oceanic lithospheres are preserved as supra-subduction ophiolites and related mafic complexes in the Appalachian-Caledonian and Variscan orogens. However, available Sm-Nd isotopic data indicate that the mantle source of these complexes was highly depleted as a result of an earlier history of magmatism that occurred prior to initiation of the Iapetus and Rheic oceans. We propose two alternative models for this feature: either the highly depleted mantle was preserved in a long-lived oceanic plateau within the Paleopacific realm or the source for the basalt crust was been recycled from a previously depleted mantle and was brought to an ocean spreading centre during return flow, without significant re-enrichment en-route. Data from present-day oceans suggest that such return flow was more likely to have occurred in the Paleopacific than in new mid-ocean ridges produced in the opening of the Iapetus and Rheic oceans. Variation in crustal density produced by Fe partitioning rendered the lithosphere derived from previously depleted mantle more buoyant than the surrounding asthenosphere, facilitating its preservation. The buoyant oceanic lithosphere was captured from the adjacent Paleopacific, in a manner analogous to the Mesozoic-Cenozoic "capture" in the Atlantic realm of the Caribbean plate. This mechanism of "plate capture" may explain the premature closing of the oceans, and the distribution of collisional events and peri-Gondwanan terranes in the Appalachian-Caledonian and Variscan orogens. © 2013 Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902511078&doi=10.1007%2fs00531-013-0925-1&partnerID=40&md5=165b2851335a9cae224eb2124de70b69
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70475
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Department of Earth Sciences, St. Francis Xavier University, PO Box 5000, Antigonish, NS, B2G 2W5, Canada; Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, T6G 2E3, Canada; British Geological Survey, Tongwynlais, Cardiff, CF15 7NE, United Kingdom; Department of Geology, University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom
Recommended Citation:
Murphy J.B.,Waldron J.W.F.,Schofield D.I.,et al. Highly depleted isotopic compositions evident in Iapetus and Rheic Ocean basalts: Implications for crustal generation and preservation[J]. International Journal of Earth Sciences,2014-01-01,103(5)