Exhumation mechanism and structure of the Sulu ultrahigh-pressure metamorphic belt, central China

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Authors:Xu Zhiqin; Zhang Zeming; Liu Fulai; Yang Jingsui; Li Haibing; Yang Tiannan; Qiu Haijun; Li Tianfu; Meng Fanchong; Chen Zhizhong; Tang Zemin; Chen Fangyuan
Author Affiliations:Primary:
Chinese Academy of Geological Sciences, Institute of Geology, Beijing, China
Volume Title:Dizhixue Bao Acta Geologica Sinica
Source:Dizhixue Bao = Acta Geologica Sinica, 77(4), p.433-450. Publisher: Science Press, Beijing, China. ISSN: 0001-5717
Publication Date:2003
Note:In Chinese with English summary. 34 refs.; illus., incl. sects., 2 plates, geol. sketch maps
Summary:The exhumation structure of the Sulu high-ultrahigh-pressure (HP-UHP) metamorphic terrain consists of superimposed ductile shear slices. The stretching lineations are WNW-ESE and the shearing direction is from ESE to WNW. The UHP retrograde metamorphic reaction accompanying the exhumation structure agrees with quartz LPO models from high temperatures (>650 °C) through medium temperatures (400-650 °C) to lower temperature (<400 °C). During the period of 150-100 Ma, extension events involved the formation of both the transtensional shear zone at the northern boundary and in the Laiyang Cretaceous basin, the emplacement of granites, and the formation of an anticlinal form with ductile-brittle normal slip structures due to curved exhumed foliation. Integrated multidisciplinary investigations indicate that a huge amount of material from the Yangtze Platform was subducted northwards beneath the North China Platform at 220-240 Ma, and then the whole HP-UHP slab was exhumed rapidly at 220-200 Ma. That is why the metamorphic rock sequence from top to bottom preserved in the exhumed slab coincides with the rock sequence in the superimposed shear slices. Seismic data reveal that the appearance of the exhumed Sulu HP-UHP metamorphic slab is characterized by a doming tongue structure. Deformation decomposition shows that the Sulu HP-UHP slab was exhumed by the mechanism of extrusion and was modified by a post-exhumation extensional event. [G.L.B.]
Sections:Petrology
Subsections:Metamorphism: regional, dynamic
Subjects:Brittle deformation; Deformation; Ductile deformation; Eclogite; Exhumation; Extension tectonics; Faults; Metamorphic belts; Metamorphic rocks; Pressure; Shear zones; Syntectonic processes; Tectonics; Ultrahigh pressure; Asia; China; Far East; North China Platform; Sulu Terrane; Yangtze Platform; Central China; Laiyang Basin
Coordinates:N343000 N343000 E1184600 E1184600
Abstract Numbers:04M/1148
Record ID:2012016496
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute.
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