Discovery of eclogite and its geological significance in Qiangtang area, central Tibet
Discovery of eclogite and its geological significance in Qiangtang area, central Tibet
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DOI：
10.1007/s11434-006-1095-3
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发表时间：
2006-05
影响因子：
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通讯作者：
Cai Li;Qing-guo Zhai;Yongsheng Dong;Xiao-Xiao Huang-Xiao
中科院分区：
文献类型：
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作者：
Cai Li;Qing-guo Zhai;Yongsheng Dong;Xiao-Xiao Huang-Xiao
榴辉岩首次发现于藏中羌塘地区，呈透镜状产出于龙木错-双湖古特提斯缝合带南缘沿着蓝闪石-白云母片岩和石榴子石-白云母片岩组成的高压变质带中。与榴辉岩共生的蓝片岩获得蓝闪石40 Ar/39 Ar年龄为220 Ma，多硅白云母40 Ar/39 Ar年龄为221.9Ma。岩石由石榴子石、绿辉石、角闪石、多硅白云母、金红石等组成，绿辉石中硬玉含量为32.7%~ 38.95%。据估计，榴辉岩的温度<500°C，压力变化范围为1.56-2.35 GPa。羌塘生态岩的发现进一步支持了中羌塘地区存在印支期缝合带的观点，对探讨该地区古海洋和古板块构造演化具有重要意义。
Eclogite is first discovered from Qiangtang area, central Tibet, which occurs as a lens in the high-pressure metamorphic belt comprising glaucophane-muscovite schist and garnet-muscovite schist, along the south margin of Lungmu Co-Shuanghu Paleo-Tethys suture. A glaucophane40Ar/39Ar age of 220 Ma and a phengite40Ar/39Ar age of 221.9 Ma have been obtained from blueschists associated with eclogite. The rock consists of garnet, omphacite, amphibole, phengite, and rutile, etc, and the jadeite content in omphacite ranges from 32.7% to 38.95%. It is estimated that the temperature of the eclogite is <500°C and pressure varies in the range of 1.56–2.35 GPa. The discovery of Qiangtang ecologite further supports that there is a suture zone of Indo-Chinese epoch in central Qiangtang area, and is very important for discssing the evolution of the paleo-ocean and paleo-plate tectonics in this area.