Acta Scientiarum Naturalium Universitatis Pekinensis

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Significances of Deep-Seated Xenolith in Cretaceous Basalt of Inner Mongolia

XU Xuan1, 3, WU Tairan1, 3, ZHANG Shuangtao1, 3, J. Byamba2, A.Amarjargal2, WANG Shiqi3, LI Zhongquan3   

  1. 1Key Laboratory of Orogenic Belts and Crustal Evolution Peking University Ministry of Education, Beijing, 100871, E-mail: twu@pku.edu.cn; 2Faculty of Earth Science, National University of Mongolia, Ulaanbaatar, Mongolia, 210000; 3School of Earth and Space Sciences, Peking University, Beijing, 100871
  • Received:2004-04-08 Online:2005-07-20 Published:2005-07-20

内蒙古四子王旗早白垩世深源捕虏体的发现及意义

许绚1,3,吴泰然1,3,张双涛1,3,J. Byamba2,A.Amarjargal2,王时麒3,李忠权3   

  1. 1造山带与地壳演化教育部重点实验室北京大学,北京,100871,E-mail: twu@pku.edu.cn;2蒙古国立大学地球科学学院,乌兰巴托,210000;3北京大学地球与空间科学学院,北京,100871

Abstract: Siziwangqi of Inner Mongolia is located on the north margin of North China Craton, the junction of North China Craton and Siberia. Granulite xenoliths are found there in Cretaceous basalt. These xenoliths are mainly plagioclase-pyroxenite. The K-Ar isotopic dating of the basalt is between 108.6--128.4 Ma. These granulite xenoliths are not only important for understanding the composition and interaction between the lower lithosphere and the mantle, but also direct evidence for Mesozoic delamination of North China Craton.

Key words: Cretaceous, lower crust, granulite xenolith, Siziwangqi area

摘要: 内蒙古四子王旗地区地处华北板块北缘,与西伯利亚板块的接合部,其早白垩世橄榄玄武岩中发现大量下地壳麻粒岩捕虏体,并可见辉石、长石捕虏晶。寄主岩石K-Ar同位素年龄在108.6~128.4 Ma之间。四子王旗地区下地壳捕虏体的发现对研究华北板块北缘中生代构造格局转化过程中深部壳幔的相互作用及物质成分的演变具有重要意义,为华北板块中生代末岩石圈拆沉事件提供了证据。

关键词: 早白垩世, 下地壳, 麻粒岩捕虏体, 四子王旗

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