柴达木盆地第四纪环境演变、构造变形与青藏高原隆升的关系

青藏高原北部柴达木盆地发育了巨厚的第四纪河湖相沉积。盆内沉积地层强烈的构造变形以及湖盆环境突变进一步证实了青藏高原经历了多期挤压隆升运动。沉积环境、介形虫和植物孢粉化石及磁性地层研究表明,自距今 2.5Ma以来,青藏高原共经历了距今2.52～2.28Ma,1.94～1.66Ma,1.38～1.1Ma,0.71～0.5Ma和 0.24～0.09Ma 5次强烈的隆升阶段,分别对应于青藏运动B幕和C幕、昆黄运动A幕和B幕以及共和运动。高原内、外 9个盆地的构造—沉积记录对比研究也进一步揭示了青藏高原隆起的整体性和阶段性。

RELATION AMONG QUATERNARY ENVIRONMENTAL EVOLUTION,TECTONIC DEFORMATION IN THE QAIDAM BASIN AND UPLIFTING OF THE QINGHAI-TIBET PLATEAU

A thick succession of Cenozoic fluvial lacustrine sediments deposited in the Qaidam Basin accompanied with strong uplifting of the Qinghai Tibet(Xizang)plateau. Intensive tectonic deformation and abrupt shift of basinal sedimentary environments from 2.5 Ma ago revealed the Qinghai Tibet plateau having experienced the most fierce uplift since the late Cenozoic. The integrated studies of sedimentary environments, Ostracoda fossils, sporo-pollen and magnetic stratigraphy indicated that the prolonged period of tectonic quiescence of the Qinghai Tibet plateau were punctuated by brief, intense interval of deformation and uplifting. Five episodic uplift movements were recognized, which occurred during 2.52～2.28 Ma ago,1.94～1.66 Ma ago, 1.38～1.1 Ma ago,0.71～0.5 Ma ago and 0.24～0.09 Ma ago respectively, and corresponding to the episodes B and C of the Qingzang orogeny, episodes A and B of the Kunhuang orogeny and the Gonghe movement. A comparative study of tectono sedimentary records in nine basins distributed in wide range of the Qinghai Tibet plateau further revealed a coincident and episodic uplift feature of the Qinghai-Tibet plateau as a whole.