晋豫间黄河峡谷黄土状沙丘的光释光年代学探讨  

OPTICALLY STIMULATED LUMINESCENCE DATING OF LOESS-LIKE SAND-DUNE ALONG THE YELLOW RIVER VALLEY BETWEEN HENAN AND SHANNXI PROVINCES

作　　者：杜金花[1,2] 卢演俦[1,3] 王旭龙[1] 康树刚[1] 

机构地区：[1]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710075 [2]中国科学院研究生院,北京100049 [3]中国地震局地质研究所地震动力学国家重点实验室,北京100029

出　　处：《第四纪研究》2010年第5期946-955,共10页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:40972124);中国科学院地球环境研究所黄土与第四纪地质国家重点实验室资助

摘　　要：通过对风陵渡-三门峡晋豫间黄河峡谷的地貌考察和1:50000地形图(1970年)的分析,初步查明了黄河南岸黄土状沙丘的分布特征。选取河南省灵宝市豫灵镇阌底约75m高的黄土状沙丘剖面进行了观测和取样。根据该剖面的粒度分布特点,选取中颗粒(40～90μm)石英进行了光释光(OSL)测年研究。采用简化SAR法测量样品的等效剂量(D_e),其中5个样品与SAR法测量的,D_e值对比,结果在误差范围内一致。对阌底剖面自上而下19个样品运用简化SAR法做了OSL年龄测定,其中8个还进行了4～11μm细颗粒石英简易多测片再生法(SMAR)OSL测年,两个粒级石英的OSL年龄测定值在测量误差范围内一致。初步结果表明,晋豫间黄河峡谷阌底黄土状沙丘发育不晚于距今约5.5万年前,并延续到全新世初期,风沙堆积速率在3.2万年前后曾出现显著变化。By the field landform investigation and the analysis of 1：50000 topographic maps （made in 1970） , there is a series of loess-like sand-dune in the Yellow River valley from the Fenglingdu to the Sanmenxia between Henan and Shannxi provinces. A profile of loess-like sand-dune near the Wendi village, Lingbao County, was selected for luminescence dating. According to the characteristics of the grain-size distribution of the sand-dune, the medium grain-size（40 - 90μm） quartz was applied to measure Equivalent dose（Do）using the Simplified SAR protocol. The De determinations obtained from both the SAR protocol and the Simplified SAR for five samples are good agreement within a standard deviation. The nineteen samples collected from the Wendi profile have been dated by the Simplified SAR for the medium grain（40 -90μm）quartz. Comparing to the fine-grained（4 -11 μm）quartz of eight samples by the Simplified Multiple Aliquot Regenerative-dose （SMAR）protocol, all OSL ages were in good agreement with those of medium grain quartz by the Simplified SAR within a reasonable error range. It may be suggested that the loess-like sand-dune could be at least developed in about 55ka ago and continued to the early Holocene,and that dune accumulation rate could be evidently changed in about 32ka ago in Yellow River valley between Shannxi and Henan Provinces on the basis of OSL dating results.

关 键 词：晋豫黄河峡谷 黄土状沙丘 光释光测年 

分 类 号：P343.5[天文地球—水文科学] P941.74[天文地球—地球物理学]