Exhumation of High-Pressure and Ultrahigh-Pressure Metamorphic Rocks from the Dabie Orogenic Belt
详细信息
- 责任者：Wang Qingchen (State Key Laboratory of Lithospheric Evolution ; Institute of Geology and Geophysics ; Chinese Academy of Sciences ; Beijing 100029 ; China)
- 刊名：Acta Petrologica Sinica
- 出版年：2013
- 卷期：29(5)
- 关键词：高压变质作用 ; high pressure metamorphism ; 超高压变质岩 ; ultrahigh pressure metamorphic rocks ; 大别山 ; Dabie Mountains
- 页码：p.1607-1620
- 图表：illus., 1 table, 74 refs.
- 分类号：0802
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
Exhumation of high-pressure ( HP) and ultrahigh-pressure ( UHP) metamorphic rocks is a geodynamic process. Although our eyes could not see the process,we can look for its foot-prints in rocks. The present paper deals with the HP-UHP rocks in the Dabie Orogenic Belt. Evidences constrain the exhumation process of the Dabie HP-UHP rocks include the following: ( 1) Structural and geophysical data record dome-shaped compressional architecture of crust resulted from exhumation and depict offsets in the Moho, which served as exhumation channel. ( 2) P-T-t data record the passing depth and time of the Dabie HP-UHP rocks,and display the southward exhumation polarity. ( 3 ) Pebble composition and Si content in detrial phengite record that HP-UHP rocks have been exhumed to surface by the Middle Jurassic. The reconstructed exhumation process include three stages: by 230Ma,three slices started to exhume one after another quickly from various depth and arrived at the middle curst in 210Ma with exhumation rates of 3 ～ 10km / Ma,and then quickly entered the upper crust by 180Ma with exhumation rate of ～ 3 km / Ma. Exhumation rate in Cretaceous is very small ( ～ 0. 1km / Ma).
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