From crustal anatexis to mantle melting in the Variscan orogen of Corsica (France): SIMS U-Pb zircon age constraints
From crustal anatexis to mantle melting in the Variscan orogen of Corsica (France): SIMS U-Pb zircon age constraints
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科西嘉岛瓦里斯造山带（法国）从地壳深熔到地幔熔融：SIMS U-Pb 锆石年龄限制
DOI：
10.1016/j.tecto.2014.07.021
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发表时间：
2014-11
期刊：
影响因子：
2.9
通讯作者：
Lin Wei
中科院分区：
文献类型：
--
作者：
Li Xian-Hua;Faure M.;Lin Wei
本文对法国科西嘉Variscan造山带杂岩和Mg-K岩浆套进行了高精度SIMS U-Pb锆石年龄测定。4种杂岩白色体锆石的结晶年龄一致，约345 Ma。西北科西嘉Calvi-IIe Rousse岩体中的4块Mg-K花岗质岩石和1块二长辉长岩包体的U-Pb锆石年龄约为330 Ma。这些新的SIMS锆石U-Pb定年结果表明，在角闪岩相条件下的区域地壳深熔在大约345 Ma时同步发生在整个科西嘉-瓦里斯坎链上。增厚地壳的熔融作用与交代地幔和上覆地壳的部分熔融作用之间约有15万年的时间间隔，形成Mg-K岩套。结合以往高温高压麻粒岩相变质作用的定年结果，确认了约360ma、345ma和330ma三个主要的离散构造热事件。我们主张在科西嘉岛的瓦里斯坎造山带内，采用一种平板断裂模型来解释地壳的热力学演化。俯冲洋岩石圈的撕裂引发软流圈上升以填补空隙，并导致上覆大陆地壳在约360 Ma发生麻粒岩相变质作用。洋俯冲岩石圈的最终断裂导致俯冲地壳向加厚的下至中地壳水平掘出。内部放射性成因加热在345 Ma左右引起地壳尺度的岩化作用。板块断裂和沉陷增强了热软流圈的上升，引起了传导的热扰动，导致交代富集的地幔岩石圈熔化，形成约330 Ma的镁钾镁质花岗岩类岩浆活动。
High-precision SIMS U–Pb zircon age determinations are conducted in this study on migmatites and Mg–K magmatic suites from the Variscan orogen of Corsica (France). Zircons from leucosomes of four migmatites yield consistent crystallization ages of ca. 345 Ma. Four Mg–K granitoid rocks and one monzogabbro enclave from the Calvi-IIe Rousse pluton of NW Corsica yield indistinguishable U–Pb zircon ages of ca. 330 Ma. These new SIMS zircon U–Pb dating results indicate that the regional crustal anatexis under amphibolite-facies condition occurred synchronously at ca. 345 Ma throughout the Corsican Variscan chain. There is a ca. 15 m.y. time interval between anatexis of the thickened crust and partial melting of the metasomatized mantle and overlying crust to form the Mg–K rock suites. In combination with the previous dating results for the high-temperature and high-pressure granulite-facies metamorphism, three major discrete tectonothermal events at ca. 360 Ma, ca. 345 Ma, and ca. 330 Ma are acknowledged. We argue for a slab break-off model accounting for thermal and mechanical evolution of the crust within the Variscan orogen of Corsica. A tearing of the subducting oceanic lithosphere initiates the asthenosphere rise to fill the void and causes the granulite-facies metamorphism of the overlying continental crust at ca. 360 Ma. Final breaking of the subducting oceanic lithosphere results in exhumation of the subducted crust to the thickened lower to middle crustal-level. Internal radiogenic heating causes crust-scale migmatization at ca. 345 Ma. Slab break-off and foundering enhance the rise of hot asthenosphere, resulting in conducted thermal perturbation that leads to melting of the metasomatised enriched mantle lithosphere to form Mg–K mafic–granitoid magmatism at ca. 330 Ma.
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影响因子：
4.5
作者：
Geisler, Thorsten;Schaltegger, Urs;Tomaschek, Frank
通讯作者：
Tomaschek, Frank
科西嘉岛的瓦里斯造山运动：新的结构和地质年代学见解及其在瓦里斯地球动力学框架中的地位
影响因子：
2.3
作者：
Melleton, Jeremie;Frei, Dirk;Li, Xianhua;Lin, Wei
通讯作者：
Lin, Wei
影响因子：
3.9
作者：
F. Poitrasson;J. Paquette;J. Montel;C. Pin;J. Duthou
通讯作者：
F. Poitrasson;J. Paquette;J. Montel;C. Pin;J. Duthou
DOI：
--
发表时间：
2012-06
期刊：
--
影响因子：
--
作者：
Anne-Sophie Tabaud
通讯作者：
Anne-Sophie Tabaud
影响因子：
1.4
作者：
M. Corsini;Y. Rolland
通讯作者：
M. Corsini;Y. Rolland