陈鑫, 许荣科, 郑有业, 王永开, 王红军, 白杰, 杜文洋, 卢锐. 青海柴北缘UHP变质带铁石观西榴辉岩峰期温度的确定及其地质意义[J]. 地质通报, 2015, 34(12): 2292-2301.
    引用本文: 陈鑫, 许荣科, 郑有业, 王永开, 王红军, 白杰, 杜文洋, 卢锐. 青海柴北缘UHP变质带铁石观西榴辉岩峰期温度的确定及其地质意义[J]. 地质通报, 2015, 34(12): 2292-2301.
    CHEN Xin, XU Rongke, ZHENG Youye, WANG Yongkai, WANG Hongjun, BAI Jie, DU Wenyang, LU Rui. The determination of peak temperature of eclogites in the west of Tieshiguan area, North Qaidam UHP of Qinghai Province, and its geological significance[J]. Geological Bulletin of China, 2015, 34(12): 2292-2301.
    Citation: CHEN Xin, XU Rongke, ZHENG Youye, WANG Yongkai, WANG Hongjun, BAI Jie, DU Wenyang, LU Rui. The determination of peak temperature of eclogites in the west of Tieshiguan area, North Qaidam UHP of Qinghai Province, and its geological significance[J]. Geological Bulletin of China, 2015, 34(12): 2292-2301.

    青海柴北缘UHP变质带铁石观西榴辉岩峰期温度的确定及其地质意义

    The determination of peak temperature of eclogites in the west of Tieshiguan area, North Qaidam UHP of Qinghai Province, and its geological significance

    • 摘要: 青海铁石观西发现大量的榴辉岩,鱼卡超高压变质带向东南延伸了40km。对铁石观西榴辉岩从地质特征、岩相学、矿物学等进行研究,岩相学显示其为典型的退变榴辉岩,保留有超高压变质峰期矿物组合(石榴子石+绿辉石+多硅白云母+金红石)。运用矿物温度计对铁石观西超高压变质峰期温度进行测量,得出温度范围为694~791℃,压力范围为2.5~2.6GPa。石榴子石环带显示,核部到边部温度升高,核部到幔部压力逐步升高,幔部到边部压力降低,表明榴辉岩经历了快速俯冲和折返速度缓慢的动力学过程。

       

      Abstract: Lots of eclogites have been found in the west of Tieshiguan, which has fulfilled the recognition of the ultrahigh pressure metamorphic belt between Yuqia and Xitie Mountain. The Yuqia ultrahigh pressure metamorphic belt extends southeastward for 40 kilometers. On the basis of geological features, petrography and mineralogy of eclogites in the west of Tieshiguan, the authors revealed that ultrahigh pressure metamorphic peak period mineral combination (garnet+omphacite+phengite+rutile) has been preserved. It is obviously of retrograde eclogites as shown by the petrographic analysis. The authors used mineralogical thermometer to measure the temperature of the ultrahigh pressure metamorphic peak period of west Tieshiguan, and the results show that the temperature and the pressure were 694-791℃ and 2.5-2.6GPa respectively. Garnet zoning shows that the temperature decreased from the core area to the edge, whereas the pressure increased from the core area to the mantle area and decreased from the mantle area to the edge, which suggests that eclogite went through a dynamic process of rapid subduction and low speed exhumation.

       

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