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Structural Elements Association of Yanshan Orogenic Belt,North China

DENG din-fu, SU Shang-guo, ZHAO Guo-chun, LIU Cui   

  1. Key Laboratory of Lithospheric Tectonics and Lithoprobe Techniques, Ministry of Education, China University of Geosciences, Beijing 100083, China
  • Received:2004-09-20 Revised:2004-09-20 Online:2004-09-20 Published:2004-09-20

Abstract: Using the concept of structural elements association of orogenic belt.we studied the evolution of Yanshan orogenic belt.The structural elements association characteristics of each stage of Yanshan orogenic belt are as follows:During the pre-and initial orogenic episode(J1),in the earlier stage of Early Jurassic,it is preorogenic extension.The structural elements associations are:triple junction rift, intraplate basalt,coal-bearing sedimentary formation;In the later stage of Early Jurassic.it is incipient orogenic compression.The structural elements associations are: northward verging fold and thrust, Jiulongshan molasse-like formation,chloritoid-staurolite-kyanite low temperature, middle-high pressure metamorphic belt.During the early orogenic episode(J2),in earlier stage of Middle Jurassic.it is syn-orogenic extension. Structural elements associations are: volcanic basins and intrusive rocks with lithosphere uplift and extension,linear distribution of volcanic rocks;In the later stage of Middle Jurassic, it is compression regime.Structural elements associations are:thrusting and folding,molasse formation.syn-tectonic intrusive rocks and am phibole facies metamorphiesm;During the peak orogenic episode(J3),in the earlier stage of Late Jurassic,it is syn-orogenic extension. Structural elements associations are:volcanic basins and intrusive rocks with lithosphere uplift and extension, planar distribution of vo1canic rocks,high-pressure trachyte,voluminous rhyolite;in the later stage of late Jurassic,it is compression structure, Structural elements associations are:thrusting and folding, molasse formation, syn-tectonic intrusive rocks and amphibole facies metamorphism,high-pressure syenite;During the earlier stage of Early Cretaceous,it is late-orogenic episode.Structural elements associations are:local compression structure,lake facies sedimentary formation,peralkaline quartz syenite,miarolitic granite,komatiitic gabbro;During the later stage of Early Cretaceous,it is post-orogenic extension episode. Structural elements associations are:normal faulting,metamorphic core complex,bimodal dikes,typical peralkaline granite and coal-bearing sedimentary formation.