摘要
基于区域TM遥感影像资料解译和野外构造地貌调查以及晚第四纪沉积物光释光测年分析,论述了青藏高原东缘复杂地貌边界带晚第四纪伸展构造及其构造地貌特征。结果显示,伸展构造主要见于下列几个构造带:沿南北走向的安宁河谷地、大凉山构造带、若尔盖盆地、岷江断裂带等。其典型的地貌特征表现为充填晚第四纪沉积物的狭窄河谷。根据盆地沉积物的地层时代和年龄推断,正断作用主要发生在中更新世时期,大约起始于早更新世末期(1.2～0.9Ma),结束于中更新世晚期(100～200ka)。晚更新世以来,构造体制转化为走滑—逆冲机制。青藏东缘中更新世伸展构造作用可能与该地貌边界带晚新生代造山后的高原垮塌有关。
This paper deals with late Quaternary extension occurred along the eastern marginal zone of the Xizang （Tibetan） Plateau, based on Landsat TM imagery interpretation, field observations and optically stimulated luminescence （OSL） dating. The results show that late Quaternary extension has been observed along the longitudinal Anninghe valley, along the Daliangshan structural zone, in the Zoige basin and in the upstream Minjiang river. The characteristic feature of these extensional structures is the elongate valley controlled by normal faults and filled with late Quaternary deposits. According to the stratigraphic ages and OSL dating results, normal faulting occurred mostly in Middle Pleistocene, beginning from latest Early Pleistocene （1.2~0.9 Ma）, and ending in earliest Late Pleistocene （100~200 ka）. Since the Late Pleistocene, the tectonic regime has changed to strike-slip and reverse faulting one. The occurrence of the Middle Pleistocene extension along the eastern margin of the Tibetan Plateau may be the response to post-orogenic collapse of this marginal zone.
出处
《地质论评》
CAS
CSCD
北大核心
2010年第6期781-791,共11页
Geological Review
基金
科技部973课题"龙门山地质构造断裂带及其与汶川蕴震动力条件分析"(编号2008CB425702)的成果
关键词
青藏高原东缘
中更新世
正断层
构造地貌
伸展作用
造山后垮塌
eastern margin of the Xizang （Tibetan） Plateau
Middle Pleistocene
normal faulting
extension
morpho-structure
post-orogenic collapse
