青海格尔木早更新世昆仑河砾岩的发现及其地质意义  

DISCOVERY OF THE EARLY PLEISTOCENE KUNLUNHE CONGLOMERATE IN GOLMUD OF QINGHAI PROVINCE AND ITS GEOLOGICAL SIGNIFICANCE

作　　者：赵希涛[1] 胡道功[2] 吴中海[2] 刘琦胜[2] 张耀玲[2,3] 薛腊梅[3] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]中国地质科学院地质力学研究所,北京100081 [3]中国地质大学地球科学与资源学院,北京100083

出　　处：《地质力学学报》2010年第1期1-10,共10页Journal of Geomechanics

基　　金：中国地质调查局项目(编号:1212010711510)资助

摘　　要：昆仑河发源于昆仑山,是格尔木河的重要支流之一。前人所报道的新近纪与第四纪地层,主要集中于昆仑山垭口地区,而在昆仑河—格尔木河谷地中,只有中更新世以来的最新地层,从而提出了发生于1.1～0.6 Ma BP间的"昆仑—黄河运动"的概念。然而在昆仑河谷中发现了厚达20 m的钙质胶结的河流相砾石层(昆仑河砾岩),其分布、特征及其与纳赤台沟组、三岔河组和低阶地沉积等上覆地层的不整合接触关系,以及ESR法测定的该砾石层2个钙质胶结物样品的年龄(分别为1 042±104 ka BP与1 269±126 ka BP)均表明,早在距今1.27～1.42 Ma之前昆仑河—格尔木河河谷已经形成,而且已深切到现今的谷底。此后河谷内的多次切割与堆积,不应是构造运动的结果,而可能是冰期与间冰期气候变化所引起的侵蚀与搬运能力变化造成的。同样,昆仑山相对于柴达木盆地的强烈隆升至少应发生于距今1.27～1.42 Ma之前。The Kunlun River originating in the Kunlun Mountains is one of main tributaries of the Golmud River.The reported Neocene and Quaternary strata are mainly distributed in the Kunlun Pass area,whereas in the valley of the Kunlun-Golmud River only occur the strata younger than the Middle Pleistocene.Therefore,a conception of the＂Kunlun-Huanghe movement＂was proposed for the time span of 1.1 to 0.6 Ma.In this paper we report the discovery of over 20m of Ca-cemented fluvial gravels in the valley of Kunlun River,named the Kunlunhe conglomerate.Its distribution,the unconformity with such overlying strata as the Nachitaigou Formation,the Sanchahe Formation and the deposits on lower terraces,as well as the ESR dating of the Ca-cemented gravels（1042±104 ka and 1269±126 ka）,all suggest that the Kunlun-Golmud River valley had been formed before 1.27～1.42 Ma,and cut deeply down to its present bottom.After that,The repeated incisions and accumulations after that were not due to tectonic movements,but to erosion and movement caused by climatic changes during the glacial-interglacial periods.Furthermore,the strong uplift of the Kunlun Mountains with respect to the Qiadam Basin should occur before at least 1.27～1.42 Ma.

关 键 词：ESR年龄测定 早更新世 砾石层 昆仑河谷发育 昆仑山隆升 

分 类 号：P534[天文地球—古生物学与地层学]