Tectonothermal evolution of the Triassic flysch in the Bayan Har Orogen, Tibetan plateau
Tectonothermal evolution of the Triassic flysch in the Bayan Har Orogen, Tibetan plateau
复制标题
青藏高原巴颜喀拉造山带三叠纪复理石的构造热演化
DOI：
10.1016/j.tecto.2017.12.020
复制
发表时间：
2018-01
期刊：
影响因子：
2.9
通讯作者：
Jian Zhou
中科院分区：
文献类型：
--
作者：
Hejing Wang;Meinert Rahn;Jian Zhou
巴彦哈尔造山带是中国西部“青藏-滇西褶皱带”的重要组成部分。它保存了从古特提斯洋关闭到喜马拉雅山脉形成的时间跨度的构造热演化的重要信息。分析了矿物组合、伊利石“结晶度”(IC)、绿泥石“结晶度”(CC)、伊利石多型、K-白云母的b晶胞尺寸、所选矿物的地质测温等低温变质指标。巴彦哈尔造山带三叠纪复理石的Kübler指数(Ki)为0.2 3~1.6 3°Δ2θ，阿尔凯指数(αi)为0.2 1~0.6 0°Δ2θ。用KI绘制的等温带描述了巴彦哈尔造山带内的一对风化带和一个风化带：西南部的“巨型玉树风化带”(长750公里，宽100公里)，中部的“扎岭-鄂陵湖风化带”(长约150公里，宽40公里)和东北部的“兴通哲风区”(面积约6万平方公里)。它们由成岩带隔开。峰期变质条件估计在280-330℃左右，属低至中(新汉普郡北部)压力型。从西南到东北方向，压力随压力的升高而略有变化。三叠纪复理石的安山变质模式与大型褶皱和断裂的关系表明，同构造变质作用为后构造变质作用。三叠纪末期塔里木地块、北中国地块和印度陆块相互作用引起的挤压作用导致古特提斯洋的闭合，导致古特提斯洋盆内三叠纪复理石的褶皱。变质作用可能是由于增加的楔形背景和埋藏引起的岩石温度升高导致地壳增厚约10千米所致。这种区域变质模式将为重建古构造古地理和青藏高原的演化史提供重要信息。
The Bayan Har Orogen comprises a major part of the “Qingzang-Dianxi fold region” in western China. It preserves important information of the tectono-thermal evolution covering the time span from the closure of the Paleo-Tethys Ocean up to the formation of the Himalayas. Low temperature metamorphic indicators, such as mineral assemblages, illite “crystallinity” (IC), chlorite “crystallinity” (CC), illite polytype,b-cell dimension of K-white micas, geothermometry of selected minerals were analyzed. The values of Kübler index (KI) of the Triassic flysch in the Bayan Har Orogen range from 0.23–1.63°Δ2θ while Árkai index (ÁI) in a range of 0.21–0.60°Δ2θ. Iso-thermal zones mapped with KI describe a pair of anchizones and an anchiregion within the Bayan Har Orogen: the “Giant Yushu Anchizone” in the southwest (extending > 750 km long and 100 km wide), the “Zaling-Eling-Lakes Anchizone” in the center (about 150 km long and 40 km wide) and the “Xing-Tong-Zhe Anchiregion” in the northeast (covering an area of roughly 60,000 km2). They are separated by diagenetic zones. Peak metamorphic conditions are estimated around 280–330 °C and a low to intermediate (N. New Hampshire) pressure type. A slight change with increasing then decreasing pressure was observed from SW to NE. The relationship between anchimetamorphic pattern of Triassic flysch and large-scale folds and faults indicates syn- to post structural metamorphism. Compression at the end of the Triassic, induced by the interaction of the Tarim, North China and Indian blocks caused the closure of the Paleo-Tethys Ocean and led to the folding of the Triassic flysch within the Paleo-Tethys Ocean basin. Anchimetamorphism may have been caused by crustal thickening of > 10 km due to an accretionary wedge setting and a temperature increase in those rocks due to burial. Such a regional metamorphic pattern would provide important information for reconstruction of palaeotectonic-palaeogeograph and the evolutionary history of Tibetan plateau.
登录
查看更多内容
影响因子：
1.8
作者：
Xu Zhi
通讯作者：
Xu Zhi
影响因子：
5.6
作者：
S. Potel;Tatiana Maison;M. Maillet;A. Sarr;M. Doublier;G. Trullenque;R. F. Mählmann
通讯作者：
S. Potel;Tatiana Maison;M. Maillet;A. Sarr;M. Doublier;G. Trullenque;R. F. Mählmann
影响因子：
2.9
作者：
A. Weislogel
通讯作者：
A. Weislogel
影响因子：
1.5
作者：
L. Warr;R. F. Mählmann
通讯作者：
L. Warr;R. F. Mählmann
影响因子：
3.9
作者：
Zhenbing She;Changqian Ma;R. Mason;Jian-wei Li;Guocan Wang;Yuhong Lei
通讯作者：
Zhenbing She;Changqian Ma;R. Mason;Jian-wei Li;Guocan Wang;Yuhong Lei