Late Cretaceous-Cenozoic Exhumation History of the L(u|¨)liang Mountains,North China Craton:Constraint from Fission-track Thermochronology  

作　　者：LI Xiaoming SONG Yougui 

机构地区：[1]Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry, the Chinese Academy of Sciences, Guangzhou 510640, China [2]State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, the Chinese Academy of Sciences, Xi＇ an 710075, China

出　　处：《Acta Geologica Sinica(English Edition)》2010年第2期296-305,共10页地质学报（英文版）

基　　金：supported by the State Key Laboratory of Loess and Quaternary Geology(Grant No.SKLLQG0507);National Natural Science Foundation of China(Grant Nos. 40572124 and 40772116);Guangzhou Institute of Geochemistry,Chinese Academy of Sciences(Grant No. 050713);This is contribution No.IS-1157 from GIGCAS

摘　　要：The Lüliang Mountains, located in the North China Craton, is a relatively stable block, but it has experienced uplift and denudation since the late Mesozoic. We hence aim to explore its time and rate of the exhumation by the fission-track method. The results show that, no matter what type rocks are, the pooled ages of zircon and apatite fission-track range from 60.0 to 93.7 Ma and 28.6 to 43.3 Ma, respectively; all of the apatite fission-track length distributions are unimodal and yield a mean length of -13 μm; and the thermal history modeling results based on apatite fission-track data indicate that the time-temperature paths exhibit similar patterns and the cooling has been accelerated for each sample since the Pliocene （c.5 Ma）. Therefore, we can conclude that a successive cooling, probably involving two slow （during c.75-35Ma and 35-5Ma） and one rapid （during c.5 Ma-0 Ma） cooling, has occurred through the exhumation of the Liiliang Mountains since the late Cretaceous. The maximum exhumation is more than 5 km under a steady-state geothermal gradient of 35℃/km. Combined with the tectonic setting, this exhumation may be the resultant effect from the surrounding plate interactions, and it has been accelerated since c.5 Ma predominantly due to the India-Eurasia collision.The Lüliang Mountains, located in the North China Craton, is a relatively stable block, but it has experienced uplift and denudation since the late Mesozoic. We hence aim to explore its time and rate of the exhumation by the fission-track method. The results show that, no matter what type rocks are, the pooled ages of zircon and apatite fission-track range from 60.0 to 93.7 Ma and 28.6 to 43.3 Ma, respectively; all of the apatite fission-track length distributions are unimodal and yield a mean length of -13 μm; and the thermal history modeling results based on apatite fission-track data indicate that the time-temperature paths exhibit similar patterns and the cooling has been accelerated for each sample since the Pliocene （c.5 Ma）. Therefore, we can conclude that a successive cooling, probably involving two slow （during c.75-35Ma and 35-5Ma） and one rapid （during c.5 Ma-0 Ma） cooling, has occurred through the exhumation of the Liiliang Mountains since the late Cretaceous. The maximum exhumation is more than 5 km under a steady-state geothermal gradient of 35℃/km. Combined with the tectonic setting, this exhumation may be the resultant effect from the surrounding plate interactions, and it has been accelerated since c.5 Ma predominantly due to the India-Eurasia collision.

关 键 词：FISSION-TRACK EXHUMATION Liiliang Mountains late Cretaceous-Cenozoic GEODYNAMICS 

分 类 号：P185.83[天文地球—天文学] P618.130.2