宁夏红寺堡盆地萨拉乌苏组地层时代重新厘定及意义  

REDEFINITION OF THE SEDIMENTARY TIME OF THE SALAWUSU FORMATION IN THE HONGSIBU BASIN,NINGXIA AND ITS SIGNIFICANCE

作　　者：崔加伟 李振宏[1] 刘锋[1] 董晓朋[1] 黄婷 赵杨 CUI Jiawei;LI Zhenhong;LIU Feng;DONG Xiaopeng;HUANG Ting;ZHAO Yang(Institute of Geomechanics,Chinese Academy of Geological Science,Beijing 100081,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081

出　　处：《地质力学学报》2018年第2期283-292,共10页Journal of Geomechanics

基　　金：中国地质调查局地质调查项目(DD20160060)

摘　　要：以沉积旋回划分为基础,采用光释光和碳十四测年技术手段,将宁夏红寺堡盆地上更新统地层时代进行了重新划分与厘定。研究结果将红寺堡盆地原定为萨拉乌苏组的湖相沉积解体为上下两套,下部湖相沉积即为传统意义上的萨拉乌苏组,上部湖相沉积结合区域地层对比结果将其重新划归为水洞沟组,总体上反映了晚更新世青藏高原东北缘发育的两期重要的古大湖事件。在深海大洋氧同位素曲线上这两期古大湖事件分别相当于MIS3与MIS5段,代表了区域上两期温暖湿润的气候环境,也与该时期全球古气候环境的变迁基本一致。同时,在这两期古大湖发育期间,存在一期重要的构造隆升事件,表现为两套地层之间存在明显的区域不整合接触,可能是青藏高原晚更新世强烈隆升的响应。因此,针对青藏高原东北缘上更新统萨拉乌苏组湖相沉积层开展系统的年代学研究,对其地层时代进行重新划分与厘定,对于研究晚更新世古大湖形成与演化、古气候变迁以及青藏高原的隆升提供了重要的地质背景资料。Based on the detailed field profile observation and stratigraphic correlation works,we re-divide the Late Pleistocene sedimentary cycle in the Hongsibu basin,Ningxia.What’s more,we also redefine the sedimentary frame of the Pleistocene in the Hongsibu basin combining with the accurate time limit from the OSL or 14 C dating results.The lacustrine deposit of the former Salawusu formation can be subdivided into the lower part which corresponds with the traditional Salawusu formation,and the upper part which corresponds with the Shuidonggou formation according to the regional stratigraphic comparison.Overall,the sedimentary process of these two parts covered two periods in which large paleo-lakes developed at the north-eastern margin of the Tibet Plateau during the Late Pleistocene.Besides that,these two periods in which large paleo-lakes developed corresponded to the marine oxygen isotope stage 3(MIS 3)and stage 5(MIS 5).During these two stages,the paleoclimate around the world was warm and wet,which means the evolution of the paleoclimate at the north-eastern margin of the Tibet Plateau took concerted action with the whole world.Moreover,there also exits a regional unconformity between these two sets of lacustrine deposits which means there developed a significant tectonic uplift during the sedimentation of these two large paleo-lakes.The tectonic uplift might have close relationship with the uplift of the Tibet Plateau during the Late Pleistocene.Therefore,the sedimentary time re-definition of the Salawusu formation is of great significance to the study of the formation and evolution of the Pleistocene large paleo-lakes,transition of the paleo-environment,and the tectonic uplift of the Tibet Plateau during the Late Pleistocene.

关 键 词：晚更新世 萨拉乌苏组 水洞沟组 古大湖 红寺堡盆地 

分 类 号：P539[天文地球—古生物学与地层学]