The Tongbai HP Metamorphic Terrane: Constraints on the Architecture and Subduction/Exhumation of the Tongbai-Dabie-Sulu HP/UHP Metamorphic Belt
详细信息
- 责任者：Liu Xiaochun (Institute of Geomechanics ; Chinese Academy of Geological Sciences ; Beijing 100081 ; China) ; Jiang Boming
- 刊名：Acta Petrologica Sinica
- 出版年：2011
- 卷期：27(4)
- 关键词：高压变质带 ; metamorphic belt of high pressure ; 超高压变质带 ; ultrahigh pressure metamorphic zones ; 板块俯冲 ; subduction ; 大别山 ; Dabie Mountains ; 苏鲁造山带 ; Su-Lu Orogenic Belt
- 页码：p.1151-1162
- 图表：3 illus., 3 tables, 84 refs.
- 分类号：0802
- 出版序号：846
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
///The Tongbai orogen is situated at the junction between the Qinling and Dabie-Sulu orogenes. The Tongbai high-pressure (HP) metamorphic terrane comprises two HP slices (I and II) and a tectonic mélange zone in the north and a blueschist-greenschist zone in the south. U-Pb, Lu-Hf, Rb-Sr and Ar-Ar multichronometric data indicate the peak metamorphism of the HP slice I taking place at 255 Ma, whereas cooling to the closure temperature of muscovite at 238 Ma. By contrast, the metamorphic ages of the HP slice II are as young as 232~220 Ma, whereas gneissic granites dominating the Tongbai complex were emplaced at 140 Ma. Based on the similarity between the Tongbai and North Dabie complexes, the authors consider that a lower P-T environment and the absence of UHP rocks in the Tongbai HP metamorphic terrane might be resulted from the shallower subduction of the South China block towards the west. The final west-narrowing architecture of the Tongbai-Dabie HP/UHP metamorphic belt is related to the Early Cretaceous extrusion towards the east.