碎屑颗粒裂变径迹热年代学

Detritai Grain Fission Track Thermochronology

碎屑颗粒热年代学是以同位素封闭温度理论（Dondson，1973）为依据，以沉积地层中年龄未发生重置的碎屑颗粒为研究对象，从而研究其沉积源区剥露特征及热演化历史的一种年代学方法。最近20年来，随着测试技术的发展，碎屑颗粒热年代学方法被广泛应用到地质学研究中。在国内，碎屑颗粒热年代学的研究尚处于起步阶段。碎屑颗粒热年代学是否可以成功地应用于地质学研究呢？通过对临夏盆地详细地研究，获得了碎屑颗粒裂变径迹热年代学数据、传统的裂变径迹热年代学数据和生长地层的数据。碎屑颗粒热年代学数据表明，构造活动发生在约8MaBP，这次构造活动使积石山开始隆升，使临夏盆地和循化盆地解体（郑德文等，2003）。来自积石山的传统的裂变径迹热年代学研究结果和临夏盆地、循化盆地的生长地层研究结果都表明临夏盆地西部的积石山于约8MaBP开始隆升。这表明碎屑颗粒热年代学可以成功地揭示构造活动的信息。

Detrital thermochronology, based on the closure temperature theory （Dondson, 1973）, is a useful method for inferring the exhumation features and the thermal history of source area by studying the unreset detrital grains deposited in strata. In the past 20 years, detrital thermochronology has been widely applied to geological researches with the advance of the analytical technology. In China, the detrital thermochronology is still in its beginning stages, and hence it is necessary to study its feasibility. Can the detrital thermochronology be applied to geological studies successfully？ Based on a detail study of Linxia basin, the authors obtained the detrital fission track data, the conventional fission data and the growth strata data. The detrital fission track data show that a tectonic activityoecurred at about 8 Ma B P, resulting in the uplift of Jishishan and disintegration of Linxia-Xunhua basin （Zheng et al., 2003）. The conventional fission track data from Jishishan and the growth strata data from Linxia basin and Xunhua basin show similar results. These similar results suggest that detrital thermochronology is a successful method for obtaining information of tectonic activities.