【摘要】 在总结青藏高原新生代构造隆升剥露过程时空差异性的基础上,揭示青藏高原的扩展与高原形成过程.古新世-始新世(65～35Ma)为受逆冲推覆作用控制不同层次的岩石抬升剥露,蚀源区主要位于甜水海、祁连山、松潘-甘孜-巴颜喀拉和冈底斯等地区;羌塘-可可西里-柴达木以及西宁-临夏地区为低海拔冲泛平原区;西北部和南部地区保持为残留海沉积区.渐新世晚期-中新世早期(25～17Ma)藏南地区(冈底斯及北喜马拉雅)强逆冲推覆导致地壳强烈加厚,在其后约17～12Ma间因均衡作用而获得现在的地表高海拔;腹地的羌塘-可可西里主体为前陆盆地发育期;北缘边缘山系现代盆-山地貌格局雏形形成.中新世中晚期(13～7Ma)以冈底斯-北喜马拉雅高海拔的原始高原为核心,高原向北扩展.高原腹地羌塘-可可西里地区盆地发生区域性的抬升,并达到相当高的海拔高度;北缘系列山系进一步崛起于盆地之上,现代盆-山地貌格局基本形成.上新世以来高原以冈底斯-北喜马拉雅为核心快速向北扩展;腹地的羌塘-可可西里-松潘-甘孜广大地区发生整体地表抬升达到现今海拔高度;北缘系列山脉加剧抬升,并向盆地方向扩展,在平均海拔增大的基础上,地貌反差也加剧;南部喜马拉雅地区在逆冲和气候的双重控制下,地貌反差加剧,系列大于7000m的异常高海拔山体形成.更多还原

【Abstract】 In this paper we deduce the expanding and forming processes of the Qinghai-Tibet plateau by summarizing the spatio-temporal difference of uplift during Cenozoic.The uplift in the Paleocene-Eocene(65-35 Ma) mainly showed rock uplift driven by thrusting in different crust levels.The major denudation areas included the Tianshuihai,the Qilian Shan,Songpan-Ganzi-Bayan Har and Gangdise etc.There appeared alluvial-pluvial plain with low elevation in the Qiangtang-Hoh Xil-Qaidam and Xining-Linxia areas,and maritime space in the western Kunlun and Himalaya areas.In the Late Oligocene-Early Miocene (25-17 Ma),intensive thrusting induced increased crust thickness in the southern Tibet (including the Gangdese and the northern Himalayan belt).Then in about 17-12 Ma,crust isostatic compensation drove the southern Tibet to reach the current high elevation.Foreland basin developed in the Qiangtang-Hoh Xil area,and basin-range lelief emerged in the northern margin of the Qinghai-Tibet plateau during the late Oligocene-early Miocene.In the middle-late Miocene (13-7 Ma),centering in the southern Tibet (the Gangdise-northern Himalayan belt),the plateau grew and expanded northwardly.The basin in the Qiangtang-Hoh Xil area uplifted regionally and reached quite high altitude.In the northern margin of the Qinghai-Tibet plateau,a series of mountains ulteriorly popped up to the basin.The modern basin-range relief formed by and large but still kept lower average attitude.Since Pliocene,the plateau has been expanding northward rapidly.Rapid unitary surface uplift has been happening in the vast area of the Qiangtang-Hoh Xil-Songpan-Garzê-Bayan Har,forming the hinterland of the current plateau.In the northern edge of the plateau,the series of mountains also have been acutely uplifting and expanding forward adjacent basin,and average attitude has also been going up.In the Himalaya,the southern edge of the plateau,the relief contrast has been strengthening by thrusting and eroding.A series of high mountains finalize,with super-elevation of more than 7 000 m,such as the Qomolangma.更多还原