青藏高原自然环境的演化与分异

青藏高原的强烈隆起导致其本身自然环境的巨大变化和自然区域的明显分异。本文阐明上新世以来青藏地区由低海拔亚热带环境向高寒环境的演化以及因全球气候冷暖波动所引起的变化。对山地垂直自然带结构类型的划分和此较研究,揭示了与山体效应密切相关的分布模式。在自然地域分异规律的背景上,探讨了水汽通道、干旱河谷和寒旱核心等高原山地独特的地生态现象。

EVOLUTION AND DIFFERENTATION OF THE PHYSICO-GEOGRAPHICAL ENVIRONMENT OF QINGHAI-XIZANG PLATEAU

The Qinghai-Xizang region with an elevation of 1000 m asl,was characterized by landscapes of the subtropical montane forest and forest-steppe in Pliocene.The intense uplifting of Qinghai-Xizang plateau.either the Himalayas in the south or the Kunlun in the north,began at the end of Pliocene and the beginning of Early Pleistocene.By a rough estimation,the accumulative uplifting of the Plateau has ammounted to 3500 m in elevation since Early Pleistocene,Three well-defined stages with alternating violent uplifts and relative stabilities are identified in the block faulted uplifting of the Plateau at the ends of pliocene,Early Pleistocene and Mid-Pleistocene,It may be manifested by three great knick points on the longitudinal profiles of rivers in the peripheries of the Plateau,