当前位置: X-MOL 学术J. Asian Earth Sci. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Barrovian metamorphism of the metapelites in NE Sikkim (Eastern Himalaya): Constraints from chemographic projection and geothermobarometry
Journal of Asian Earth Sciences ( IF 3 ) Pub Date : 2021-01-14 , DOI: 10.1016/j.jseaes.2021.104673
Suparna Tewari , Divya Prakash , Manoj Kumar Yadav , Vedika Srivastava

The Sikkim Himalaya is mostly constituted of Proterozoic metapelites and metavolcanics of the Daling Group and high-grade gneisses and metasediments of the Darjeeling Group. Metapelitic schists and gneisses of the Sikkim Himalaya show an inverted sequence of metamorphic rocks ranging from lower greenschist facies (chlorite zone) to upper amphibolite facies (sillimanite + K-feldspar zone). The relative XMg in the minerals varies as: garnet > staurolite > biotite > muscovite. The P-T evolution of the study area has been constrained through the use of an internally consistent winTWQ programme and Perple_X software in the MnNCKFMASHTO model system. The combination of these two approaches demonstrates that the schists and gneisses have experienced a range of pressure and temperature with increasing grade. Constraints on the interpretation of mineral reactions and metamorphic history provided by pseudosection modelling for mineral proportions suggest the peak metamorphic temperature as ~750 °C and pressure ~7.5 kbar. The proposed prograde P-T path implies that the rocks from the study area may have resulted from a single metamorphic event with continuous changes in pressure and temperature. The conclusions made on the basis of the study of metamorphic event in the area and the regeneration of the reaction history adheres to classical Barrovian type metamorphism. The tectonic implication of such a metamorphic evolution is also discussed in the present work. Finally, we conclude that the possible explanation for the exhumation in this section of Himalaya may most likely be explained with the help of the channel flow model.



中文翻译:

NE Sikkim(东部喜马拉雅山)中变质岩的Barrovian变质作用:化学投影和地热气压计的限制

锡金喜马拉雅山主要由大凌群的元古代变质岩和变火山岩以及大吉岭群的高级片麻岩和变质沉积物组成。锡金喜马拉雅山的变岩片岩和片麻岩显示出从低绿片岩相(绿泥石带)到上闪石岩相(硅线石+钾长石带)的变质岩的倒置序列。相对X Mg矿物质中的含量变化如下:石榴石>陨石>黑云母>白云母。通过使用内部一致的winTWQ程序和MnNCKFMASHTO模型系统中的Perple_X软件,研究区域的PT演变受到了限制。两种方法的结合表明,片岩和片麻岩经历了一定的压力和温度范围,且等级不断提高。伪剖面模型对矿物比例的解释对矿物反应和变质历史的解释的限制表明,最高变质温度为〜750°C,压力为〜7.5 kbar。拟议的渐进式PT路径暗示研究区域的岩石可能是由于压力和温度连续变化的单个变质事件造成的。在对该区域变质事件的研究和反应历史的再生的基础上得出的结论遵循经典的Barrovian型变质。在本工作中还讨论了这种变质作用的构造意义。最后,我们得出结论,最有可能在渠道流模型的帮助下解释了喜马拉雅山这一段尸体发掘的可能解释。

更新日期:2021-01-25
down
wechat
bug