地理学报 ›› 2011, Vol. 66 ›› Issue (5): 698-708.doi: 10.11821/xb201105012

• 自然地理 • 上一篇    下一篇

河套盆地西山咀凸起区湖相地层的发现及其测年

范天来, 范育新, 魏国孝   

  1. 兰州大学西部环境教育部重点实验室, 兰州 730000
  • 收稿日期:2011-03-07 修回日期:2011-03-22 出版日期:2011-05-20 发布日期:2011-07-13
  • 通讯作者: 范育新(1975-), 男, 副教授, 主要从事干旱区湖泊和沙漠的光释光年代学研究。E-mail: yxfan@lzu.edu.cn E-mail:yxfan@lzu.edu.cn
  • 作者简介:范天来(1984-), 男, 博士研究生. E-mail: fantl2004@hotmail.com
  • 基金资助:

    973 项目(2010CB950202); 国家自然科学基金项目(40972116)

New Findings and Dating of Lacustrine Sediments in the Xishanzui Subuplift, Hetao Basin

FAN Tianlai, FAN Yuxin, WEI Guoxiao   

  1. MOE Key Laboratory of West China's Environmental Systems, Lanzhou Universsity, Lanzhou 730000, China
  • Received:2011-03-07 Revised:2011-03-22 Online:2011-05-20 Published:2011-07-13
  • Supported by:

    973 Project, No.2010CB950202; National Natural Science Foundation of China, No.40972116

摘要: 在位于河套盆地内部的西山咀凸起区发现了典型的湖滩岩、湖蚀平台和一套较完整的湖相沉积地层。基于海拔高程的推断,地貌和地层沉积记录指示西山咀地区曾经存在过一个海拔达到1080 m上下的古湖面。完整的沉积地层反映西山咀凸起区经历了深湖相—滨湖相—冲洪积相—风成堆积的演变过程。光释光测年结果表明,在距今65 ka 前后,“吉兰泰—河套”古大湖在西山咀地区曾经连通;但在距今约50~30 ka 湖面再没有上涨。这一研究表明:在MIS 3 阶段某一时期,该地区的古湖面发生衰退。随后,再没有发育高于“吉兰泰—河套”古大湖最高湖面的湖泊。

关键词: 湖相沉积, 光释光年代, 西山咀凸起区, 河套盆地, 第四纪

Abstract: A complete sedimentary profile composed mainly of typical lacustrine sediments including beachrock and cut-and-built platform located in the Xishanzui subuplift, Hetao Basin, has been found. The geomorphological and stratigraphic evidence indicates that there was a paleolake with its highest lake up to 1080 m a.s.l. Stratigraphic analysis of the profile indicates that this subuplift experienced an environmental change from a deep lake to a shallow lake and then to non-lake environment (suggested by alluvial/diluvial sediments). Optical dating results support that Xishanzui subuplift was actually covered by a deep water lake, potentially the Megalake "Jilantai-Hetao" at around 65 ka BP when the lake reached its highest level. And no lake level has exceeded the highest level inferred from sedimentary sequence in the profile.

Key words: lacustrine sediments, optical dating, Xishanzui subuplift, Hetao Basin, Quaternary