Ultra-deep subduction of Yematan eclogite in the North Qaidam UHP belt, NW China: Evidence from phengite exsolution in omphacite
Ultra-deep subduction of Yematan eclogite in the North Qaidam UHP belt, NW China: Evidence from phengite exsolution in omphacite
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柴北缘超高压带野马滩榴辉岩超深俯冲：绿辉岩中多白硅白云母出溶的证据
DOI：
10.2138/am-2015-4899
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发表时间：
2015-08
影响因子：
3.1
通讯作者：
Zhang Guibin
中科院分区：
文献类型：
--
作者：
Han, Lei;Zhang, Lifei;Zhang Guibin
摘要描述了柴达木北部UHP带叶马滩榴辉岩中辉长石中的辉长石溶出。矿物学研究表明，叶马滩榴辉岩前体辉石中K2O含量高达1.16 wt%， H2O含量为~10 000 ppm。实验研究证明，这种复辉石在高于6 GPa（900°C）的压力下形成。利用Grt-Omp-Ph地温计，获得了与石榴石伴生辉石中辉石在挖掘过程中析出的压力-温度条件为3.68 GPa和892℃。我们的结论是，俯冲榴辉岩中的辉辉斜辉石可能作为一种强大的介质，将水和钾输送到地球内部深处。研究结果表明，柴达木北部UHP变质带叶马滩榴辉岩可能是在200 km以上的深度俯冲而出的。
Abstract Phengite exsolution in omphacite from the Yematan eclogite, North Qaidam UHP belt, NW China, is described. Mineralogical investigations show that the precursor omphacite in the Yematan eclogite contains up to 1.16 wt% K2O and ~10 000 ppm H2O. Experimental studies document this omphacite to be formed at pressures higher than 6 GPa (at 900 °C). The pressure-temperature conditions of 3.68 GPa and 892 °C for phengite exsolution in omphacite associated with garnet during the exhumation were obtained by using Grt-Omp-Ph geothermobarometer. We conclude that omphacitic-clinopyroxene in subducted eclogites may act as a robust medium to transport H2O and potassium deep into the interior of the Earth. This study suggests that the Yematan eclogite in North Qaidam UHP metamorphic belt, NW China, may have been subducted and exhumed from depths of more than 200 km.
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影响因子：
3.1
作者：
Shuguang Song;Lifei Zhang;J. Chen;J. Liou;Y. Niu
通讯作者：
Shuguang Song;Lifei Zhang;J. Chen;J. Liou;Y. Niu
影响因子：
1.5
作者：
K. Okamoto;S. Maruyama
通讯作者：
K. Okamoto;S. Maruyama
影响因子：
3.5
作者：
E. Schmädicke;W. Müller
通讯作者：
E. Schmädicke;W. Müller
影响因子：
1.5
作者：
Kazuaki Okamoto;J. Liou;Yoshihide Ogasawara
通讯作者：
Kazuaki Okamoto;J. Liou;Yoshihide Ogasawara
影响因子：
3.4
作者：
Carswell, DA;OBrien, PJ;Zhai, M
通讯作者：
Zhai, M