内蒙古大青山逆冲推覆体系中生代逆冲构造活动的~(40)Ar-~(39)Ar定年

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	内蒙古大青山逆冲推覆体系中生代逆冲构造活动的~(40)Ar-~(39)Ar定年; Ar-40-Ar-39 dating of the Mesozoic thrusting in Daqingshan thrust-nappe system, Inner Mongolia, China.
	张进江 ; 戚国伟 ; 郭磊 ; 刘江
刊名	岩石学报
	2009
关键词	大青山逆冲推覆体系逆冲作用千糜岩 ~(40) Ar~(39)Ar定年 Daqingshan thrust-nappe system Thrusting Phyllonite Ar-40-Ar-39 dating
英文摘要	内蒙古大青山呼和浩特段北侧发育3条走向北东东、指向北西的逆冲断层,并与被其分割的3个逆冲席体及一个原地系构成大青山逆冲推覆体系。逆冲断层上盘底部发育较深层次的糜棱岩,下盘顶部多发育低温的千糜岩。本研究在构造地质调查基础上,结合宏-微观岩石矿物学分析,采用~(40)Ar-~(39)Ar定年对该逆冲体系的活动时间进行约束。逆冲断层带内3个千糜岩绢云母~(40)Ar-~(39)Ar年龄范围为120～119Ma,另一样品给出了120Ma的概率统计峰值年龄。千糜岩为低温同变形变质产物,细粒绢云母为同变形新生矿物,其~(40)Ar-~(39)Ar年龄可代表变形年龄。侵位在断层内弱变形的花岗闪长岩为同构造晚...; The northern Daqingshan orogen in Hohhot area is tectonically characterized by a northwest-directed thrust-nappe system, the Daqingshan thrust-nappe system, which consists of three east-northeast trending thrusts, three nappes and an autochthon. Higher-grade mylonite was formed at the bases of the hanging walls of the till-Lists, while lower-grade phyllonite was produced oil the top of the footwalls. Based on structural geological investigation and integrating macro-/micro-analyses of petrology and mineralogy, this study adopts Ar-40-Ar-39 dating method to constrain the deformation time of the Daqingshan thrust-nappe system. Three sericite samples of phyllonite give a Ar-40-Ar-39 age range of 120 similar to 119Ma and the other sample presents a peak age of 120Ma in the age-probability spectrum. Phyllonite was formed by a deformation at low temperatures and the fine-graded sericite in it was new-born syn-deformational mineral, therefore the scricite Ar-40-Ar-39 age can represent the deformation time very well. A weak-deformed granodiorite (like intruding the thrust. indicates all emplacement in a late deformational stage, and its hornblende Ar-40-Ar-39 dating presents a lower-limitation age of 121Ma for the cooling of and the statistical peak age is also 119Ma. The lower-temperature phyllonite should be formed in a late stage of the deformation because higher-temperature mylonite developed at the bases of the nappes. Therefore, the thrusting of the Daqingshan thrust-nappe system must have been in its late deformational stage during the time form 120 to 119Ma.; SCI(E); 中文核心期刊要目总览(PKU); 中国科技核心期刊(ISTIC); 中国科学引文数据库(CSCD); 5; 03; 609-620; 25
语种	中文
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/49972]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	张进江,戚国伟,郭磊,等. 内蒙古大青山逆冲推覆体系中生代逆冲构造活动的~(40)Ar-~(39)Ar定年, Ar-40-Ar-39 dating of the Mesozoic thrusting in Daqingshan thrust-nappe system, Inner Mongolia, China.[J]. 岩石学报,2009.
APA	张进江,戚国伟,郭磊,&刘江.(2009).内蒙古大青山逆冲推覆体系中生代逆冲构造活动的~(40)Ar-~(39)Ar定年.岩石学报.
MLA	张进江,et al."内蒙古大青山逆冲推覆体系中生代逆冲构造活动的~(40)Ar-~(39)Ar定年".岩石学报 (2009).