Bainang Terrane, Yarlung–Tsangpo suture, southern Tibet (Xizang, China): a record of intra-Neotethyan subduction–accretion processes preserved on the roof of the world
Bainang Terrane, Yarlung–Tsangpo suture, southern Tibet (Xizang, China): a record of intra-Neotethyan subduction–accretion processes preserved on the roof of the world
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DOI：
10.1144/0016-764903-099
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发表时间：
2004-05
影响因子：
2.7
通讯作者：
S. Ziabrev;J. Aitchison;A. Abrajevitch;Badengzhu;Aileen M. Davis;Hui Luo
中科院分区：
文献类型：
--
作者：
S. Ziabrev;J. Aitchison;A. Abrajevitch;Badengzhu;Aileen M. Davis;Hui Luo
白囊山是一个洋内岛弧俯冲杂岩，白垩纪特提斯洋岩被增生到其中，保存在西藏雅鲁藏布缝合带内。野外填图建立的岩石地层序列记录了特提斯域中部不同地区从晚三叠世到中白垩世的漫长沉积历史。这些岩石被保存在一个向南叠瓦状逆冲断层叠层薄（101公里厚）向北挤压构造片。五个岩石构造单元被绘制在岩石圈，这些单位被分配到两个不同的域。堆积在新特提斯岛北侧的北方板块可能被大洋中脊与南方板块隔开。详细的放射虫生物地层学被用来限制沉积事件的时间在每个道。北方地块的大洋板块地层学记录了其向北移动和白垩纪中期（阿普第阶晚期）向南洋内俯冲带的靠近。南部地区的岩石发育在靠近印度次大陆的位置，经历了热构造沉降和中侏罗世基性碱性板内岩浆作用。它们可能是在白垩纪晚期增生的。整个地体的构造样式变化表明不同深度的变形和楔形体的垂直生长，而不是侧向加积。整体构造地层学的ESTA反映了它的发展在一个遥远的洋内设置。
The Bainang terrane, an intra-oceanic island arc subduction complex into which Tethyan oceanic rocks were accreted during the Cretaceous, is preserved within the Yarlung–Tsangpo suture zone of Tibet. The lithostratigraphic succession established from field mapping records a long history of sedimentation in different portions of the central Tethyan domain from Late Triassic to mid-Cretaceous time. These rocks are preserved within a south-verging imbricate thrust stack of thin (≪1 km thick) northward younging tectonic slices. Five lithotectonic units were mapped in the terrane and these units are assigned to two distinct tracts. The northern tract, which accumulated on the north side of Neotethys, was probably separated from its southern counterpart by a mid-ocean ridge. Detailed radiolarian biostratigraphy is used to constrain the timing of depositional events within each tract. Oceanic plate stratigraphy of the northern tract records its northward travel and mid-Cretaceous (late Aptian) approach towards a south-facing intra-oceanic subduction zone. Rocks in the southern tract developed closer to the Indian subcontinent and experienced thermotectonic subsidence and Mid-Jurassic basic alkaline intraplate magmatism. They were probably accreted late in the Cretaceous. Variations in structural style across the terrane indicate deformation at different depths and vertical growth of the wedge rather than lateral accretion. The overall tectonostratigraphy of the terrane reflects its development in a remote intra-oceanic setting.