青藏高原渐新世构造岩相古地理

Oligocene tectonic lithofacies paleogeography of the Tibetan Plateau

在研究区已发表的渐新统资料的基础上,分析了青藏高原渐新世残留盆地的构造背景、岩石地层序列,并对青藏高原渐新世构造岩相古地理特征进行了讨论,该时期总体地势格局仍为东高西低,塔里木、柴达木、羌塘、可可西里、成都等地区主体表现为大面积的压陷湖盆沉积,冈底斯、喜马拉雅和喀喇昆仑等大面积隆升,沿雅鲁藏布江自东向西的古雅江河形成。渐新世构造岩相古地理的演化特征揭示出该时期青藏高原及邻区构造隆升与沉积响应的耦合关系,划分出2个强隆升期,分别是强隆升期A(34～30Ma)和强隆升期B(25～23Ma)。

Based on the data obtained from 1：250 000 geological mapping conducted by CGS during 1996-2008 and the previous studies of Oligocene strata, the authors investigated the evolution of the Oligocene tectonic lithofacies paleogeography in the Tibetan Plateau. The paleogeographic configuration remained high in elevation on the eastern side and low in the western side; depressed basins were distributed in Tarim, Qaidam, Qiangtang, Hoh Xil and Chengdu; uplifted and erosional areas lay in Gangdist, Himalayan and Karakorum; and the paleo-Yarlung Zangbo River flowed from eastern Nang County to western Khalatse. The evolution charac- teristics of the Oligocene tectonic-lithofacies paleogeography responded to the tectonic uplift of the Tibetan Plateau, with two strong uplift stages existent during 34-30Ma （Stage A） and 25-23Ma （Stage B）.