Closure temperature of(U-Th)/He system in apatite obtained from natural drillhole samples in the Tarim basin and its geological significance  

作　　者：CHANG Jian QIU NanSheng 

机构地区：[1]State Key Laboratory of Petroleum Resource and Prospecting,China University of Petroleum,Beijing 102249,China [2]Basin and Reservoir Research Center,China University of Petroleum,Beijing 102249,China

出　　处：《Chinese Science Bulletin》2012年第26期3482-3490,共9页

基　　金：supported by the National Natural Science Foundation of China(41125010 and 41072103);the National Basic Research Program of China(2011CB201101)

摘　　要：The apatite(U-Th)/He thermochronometry has been used to study the tectono-thermal evolution of mountains and sedimentary basins for over ten years.The closure temperature of helium is important for the apatite(U-Th)/He thermochronometry and has been widely studied by thermal simulation experiments.In this paper,the apatite He closure temperature was studied by establishing the evolutionary pattern between apatite He ages and apatite burial depth based on examined apatite He ages of natural samples obtained from drillholes in the Tarim basin,China.The study showed that the apatite He closure temperature of natural samples in the Tarim basin is approximately 88±5℃,higher than the result(～75℃) obtained from the thermal simulation experiments.The high He closure temperature resulted from high effective uranium concentration,long-term radiation damage accumulation,and sufficient particle radii.This study is a reevaluation of the conventional apatite He closure temperature and has a great significance in studying the uplifting events in the late period of the basin-mountain tectonic evolution,of which the uplifting time and rates can be determined accurately.The apatite （U-Th）/He tbermochronometry has been used to study the tectono-thermal evolution of mountains and sedimentary basins for over ten years. The closure temperature of helium is important for the apatite （U-Th）/He thermochronometry and has been widely studied by thermal simulation experiments. In this paper, the apatite He closure temperature was studied by estab- lishing the evolutionary pattern between apatite He ages and apatite burial depth based on examined apatite He ages of natural samples obtained from drillholes in the Tarim basin, China. The study showed that the apatite He closure temperature of natural samples in the Tarim basin is approximately 88＋5~C, higher than the result （~75~C） obtained from the thermal simulation exper- iments. The high He closure temperature resulted from high effective uranium concentration, long-term radiation damage accu- mulation, and sufficient particle radii. This study is a reevaluation of the conventional apatite He closure temperature and has a great significance in studying the uplifting events in the late period of the basin-mountain tectonic evolution, of which the uplift- ing time and rates can be determined accurately.

关 键 词：塔里木盆地 封闭温度 磷灰石 地质意义 钻孔 热模拟实验 样本 自然 

分 类 号：P619.213[天文地球—矿床学]