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干旱区地理 ›› 2014, Vol. 37 ›› Issue (3): 439-446.

• 地表过程研究 • 上一篇    下一篇

临河凹陷晚更新世以来沉积地层的光释光年龄

刘哲,赵华,王成敏,吉云平,张翼龙,刘林敬,赵红梅,毕志伟,刘海坤   

  1. (中国地质科学院水文地质环境地质研究所, 河北    石家庄    050061)
  • 收稿日期:2013-08-12 修回日期:2013-11-04 出版日期:2014-05-25
  • 通讯作者: 赵华. E-mail:zhaohua65@163.com
  • 作者简介:刘哲(1988-),女,硕士研究生在读,研究方向为第四纪地质学. E-mail:liuzhe1130@163.com
  • 基金资助:

    中国地质调查局地质调查项目(1212010913010及12120113015600);中国地质科学院水文地质环境地质研究所基本科研业务费项目(SK201201)资助

OSL ages of sedimentary layers in Linhe Depression since Late Pleistocene

LIU  Zhe,ZHAO  Hua,WANG  Cheng-min,JI  Yun-ping,ZHANG  Yi-long,LIU  Lin-jing,ZHAO  Hong-mei,BI  Zhi-wei,LIU  Hai-kun   

  1. (Institute of Hydrogeology and Environmental Geology, CAGS, Shijiazhuang  050061, Hebei, China)
  • Received:2013-08-12 Revised:2013-11-04 Online:2014-05-25

摘要: 河套盆地沉积有较厚的第四纪河湖相地层,大量的第四纪研究工作在该区开展,但地层划分缺乏年代数据的支撑,尤其是西部临河凹陷区,年龄数据的短缺严重影响了河套地区第四纪地层系统的对比研究。基于临河凹陷3个钻孔岩芯,分析光释光年代测定的可靠性,确定临河凹陷晚更新世以来地层年代,划定晚更新统底板埋深约150 m,顶板埋深自西向东由约9 m增到约15 m。结合钻孔岩性资料,该区气候变化为:晚更新世早期(约130~80 ka)主要为河流相沉积,气候较为干旱;晚更新世中期(约80~40 ka)为河流相与湖泊、洼地相交替沉积,气候较为湿润;晚更新世晚期(约40~10 ka)主要为河流相沉积,气候较为干旱;全新世(约10 ka)以来为湖相、洼地相沉积环境,起初气候条件略湿,逐渐转干。临河凹陷区光释光年龄的测定填补了河套盆地地层研究中绝对年代缺乏的不足,为分析环境演化与区域对比提供了年代依据。

关键词: 临河凹陷, 晚更新世, 光释光年龄

Abstract: Many studies have been carried out in the Hetao Basin between Inner Mongolia and Ningxia Province,China because of the thick Quaternary lacustrine sedimentary layers. However,the lack of absolute ages,especially in the west part,is the major obstacle to compare the regional Quaternary strata in the Hetao Basin. Samples from three drill cores in the north of the Linhe Depression were collected. OSL signals from fine grain quartz were used to determine the ages of sedimentary layers. The method used in the paper is the Simplified Multiple Aliquot Regenerative-dose (SMAR) protocol. The residual signals from modern water-laid sediment show that the sediments had been bleached well,which is the basis for OSL dating. And the results of the dose recovery test indicate that a sample having been given a dose of 249.67 Gy was determined as 257.50±25.67 Gy. The error was 3.13%,within acceptable limits. In addition,no saturation was observed in the curves of the samples. As a result,it is proper to determine the ages of sediments in this area using OSL method.Based on the lithology and the OSL ages of 3 cores in the Linhe Depression,the bottom margin of Late Pleistocene series was about 150 m,while the top boundary ranged from 9 m in the west to 15 m in the east. Moreover,The OSL data of the Linhe Depression are indispensible for analyzing climate changes and regional comparing for the Hetao basin. The results illustrate that there were five change stages of climate in the Linhe Depression:(1)During the late period of Middle Pleistocene(200-130 ka),the climate was humid;(2)During the early period of Late Pleistocene(130-80 ka),it became arid;(3)During the middle period of Late Pleistocene (80-40 ka),the weather was relatively humid;(4)During the late period of Late Pleistocene(40-10 ka),it was dry;(5)During the Holocene(10 ka up to now),the climate was humid at first and then getting drier.

Key words: the Linhe Depression, Late Pleistocene, OSL ages

中图分类号: 

  • P534.63