地学前缘 ›› 2007, Vol. 14 ›› Issue (6): 189-196.

• 论文 • 上一篇    下一篇

岷江上游近两万年前发生了什么事件?

王兰生; 王小群; 许向宁; 崔杰;

  

  • 出版日期:2008-06-30 发布日期:2008-06-30
  • 基金资助:

    国家自然科学基金资助项目(40342012);; 高等学校博士学科点专项科研基金资助项目(2004616012)

What happened on the upstream of Minjiang River in Sichuan Province 20 000 years ago

  • Online:2008-06-30 Published:2008-06-30

摘要:

在对岷江1933年叠溪古镇地震滑坡调查研究中,对较场大滑坡上覆盖的较古老的土黄色厚土层进行详细研究,发现并确认这是一套静水环境下的河湖相沉积物,定名为叠溪古堰塞湖相沉积。这套湖相沉积物厚度最大可达200余m,根据14C测试,形成于约两万年以前。此后在叠溪下游以及岷江支流杂谷脑河中又发现了几个古堰塞湖沉积物,测年初步判定,也都形成于距今两万年左右。这一事实揭示两万年以前岷江上游曾发生过一次重大的变动,系列堰塞湖几乎在同一时期出现,形成了特殊的生态环境,消亡过程必然对其下游乃至川西平原环境的演化发生重要影响。堰塞湖沉积物中记载了地质环境和古气候环境变化的信息,是深入系统研究青藏高原前缘地质环境近期演化规律的极为可贵的资料。文中对这些古堰塞湖作了简要介绍,并就一些主要问题进行初步讨论。

关键词:

岷江, 古堰塞湖, 地质环境, 地质灾害,

Abstract:

A huge natural paleo-dammed lake deposit named “Diexi paleo-dammed lake” in Diexi ancient county was discovered in 1999. It is situated above the basin of the upper Minjiang River in Sichuan Province, China. The thickness of this lacustrine deposit is variable, reaching up to 200 m at some locations. Carbon-14 chronology has shown that this lacustrine deposit was formed about 20 000 years ago. Subsequently, other smaller paleo-dammed lake deposits have been discovered downstream of the Diexi area above the ...

Key words:

Minjiang River, paleo-dammed lake, geological environment, geological disaster,