Melting of mafic slab and mantle peridotite during ridge subduction of the Proto-Tethys Ocean (Qilian Orogen, NW China)
Melting of mafic slab and mantle peridotite during ridge subduction of the Proto-Tethys Ocean (Qilian Orogen, NW China)
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原特提斯洋山脊俯冲期间镁铁质板片和地幔橄榄岩的熔融（中国西北部祁连造山带）
DOI：
10.1016/j.lithos.2021.106588
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发表时间：
2022-02
期刊：
影响因子：
3.5
通讯作者：
Su Li
中科院分区：
文献类型：
--
作者：
Jinran Qiao;Dong JinLong;Mark B. Allen;Chao Wang;Mark B. Allen;Su Li
洋脊俯冲和诱导板片窗口对于了解现今和古代俯冲带中弧形岩浆作用的产生和年轻地壳的生长都具有重要意义。洋脊的物理条件控制着海脊俯冲过程中岩浆的成分，因此岩浆成分可以作为古造山带海脊俯冲的标志。本文对北祁连造山带北祁连造山带内的苏钠流纹岩和同时存在的蛇绿岩杂岩(玄武岩/辉长岩-辉长岩和方辉橄榄岩)进行了岩石学、地球化学和年代学研究。钠安质流纹岩为低Sr/Y英云闪长岩-奥长花岗岩，具有亏损的Sr-Nd同位素组成，表明其起源于449±2.9 Ma的正常洋中脊玄武岩(N-MORB)的熔融。相平衡和地球化学模拟证实，钠长流纹岩是在3-5Kbar/780-840°C由N-MORb源部分熔融形成的。玄武岩/辉绿岩具有与典型N-MORB岩相似的地球化学特征，辉长岩给出的锆石U-Pb年龄为450±2.5 Ma。玄武岩/玄武岩的成因类似于洋脊俯冲过程中常见的“吹炬”效应。方辉橄榄岩的矿物组成与深海橄榄岩相似，平衡温度为1230-1460℃，表明大陆边缘存在热的软流圈地幔。结果表明，在原特提斯洋脊俯冲过程中，上升地幔橄榄岩和俯冲洋壳在板条窗口内发生了完整的熔融过程。这些结果对了解太古界至现代地体中广泛保存的低Sr/Y英云闪长岩-奥长花岗岩的成因也具有重要意义。·钠长流纹岩是N-MORB在3-5Kbar/780-840°C时的部分熔融产物。同时的镁铁质岩是在山脊俯冲过程中的吹炬效应形成的。·浅层熔融过程表明原特提斯洋的海脊俯冲。
Ocean-ridge subduction and the induced slab windows are important to understand the generation of arc magmatism and growth of juvenile crust both in present and ancient subduction zones. The physical conditions of oceanic ridges control the compositions of magmas during ridge subduction, and therefore magmatic composition can act as a marker of ridge subduction in ancient orogenic belts. Here we present the petrological, geochemical and geochronological studies for sodic rhyodacites and a concurrent ophiolite complex (basalt/dolerite-gabbro and harzburgite) within the North Qilian orogen, NW China. The sodic rhyodacites are low Sr/Y tonalite-trondhjemite with depleted Sr Nd isotopic compositions, suggesting derivation from melting of normal mid-ocean-ridge basalts (N-MORB) at 449 ± 2.9 Ma. Phase equilibrium and geochemical modeling confirm that the sodic rhyodacites formed via the partial melting of N-MORB sources at 3–5 kbar/780–840 °C. The basalts/dolerites exhibit similar geochemical characteristics to typical N-MORB rocks, and the gabbro gives zircon U Pb age of 450 ± 2.5 Ma. The petrogenesis of the basalts/dolerites is similar to the “blow-torch” effect often seen during ocean-ridge subduction. The harzburgites are similar to abyssal peridotites in mineral compositions and have equilibrium temperatures of 1230–1460 °C, suggesting the obduction of a hot asthenospheric mantle on the continental margin. Our results show the integrated melting processes of the upwelling mantle peridotite and the subducted oceanic crust within the slab window during ridge subduction of the Proto-Tethys Ocean. These results are also significant in understanding the petrogenesis of low Sr/Y tonalite-trondhjemites, which are widely preserved in Archean to modern terranes. • Sodic rhyodacites are partial melting products of N-MORB at 3–5 kbar/780–840 °C. • The concurrent mafic rocks are formed by blow-torch effect during ridge subduction. • The shallow melting processes indicate the ridge subduction of Proto-Tethys Ocean.
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影响因子：
1.8
作者：
Wu Fuyuan;Wan Bo;Zhao Liang;Xiao Wenjiao;Zhu Rixiang
通讯作者：
Wu Fuyuan;Wan Bo;Zhao Liang;Xiao Wenjiao;Zhu Rixiang
影响因子：
3.9
作者：
Shuguang Song;Lifei Zhang;Y. Niu;L. Su;B. Song;Dunyi Liu
通讯作者：
Shuguang Song;Lifei Zhang;Y. Niu;L. Su;B. Song;Dunyi Liu
影响因子：
0.5
作者：
W. Taylor
通讯作者：
W. Taylor
影响因子：
1.8
作者：
Song Shuguang;WU ZhenZhu;Yang Liming;Su Li;X. Xiaohong;W. Chao;Dong Jinlong;Zhou ChenAo;BI HengZhe
通讯作者：
Song Shuguang;WU ZhenZhu;Yang Liming;Su Li;X. Xiaohong;W. Chao;Dong Jinlong;Zhou ChenAo;BI HengZhe
DOI：
10.1016/j.grj.2016.06.001
发表时间：
2016-12
期刊：
GeoResJ
影响因子：
--
作者：
Linqi Xia;Xiangmin Li;Jiyuan Yu;Guo-Qiang Wang
通讯作者：
Linqi Xia;Xiangmin Li;Jiyuan Yu;Guo-Qiang Wang