青藏高原喀斯特的若干问题

青藏高原灰岩出露面积不广,但具多种成因的喀斯特形态。现代山区的石峰等是由寒冻风化和冰川作用所形成,属冰缘冰川喀斯特;高原内部的许多洞穴及其堆积物,以及东南部的丘陵洼地等由溶蚀侵蚀作用所形成,属古喀斯特;高原内部和边缘地区,在钙华或河成钙华形成中,生物残体仅起凝结核作用,喀斯特泉物理化学性质的变化起决定作用。因此青藏高原兼有在现代气候条件下和古气候条件下形成的喀斯特。

SOME PROBLEMS OF KARST ON QINGHAI-XIZANG PLATEAU

1.There are "peak forest"with an altitude above 3,800m on Qinghai-Xiang Plateau,which formed under cryogenic weathering and gravity action of limestone. They belong to periglacial karst and develop accompanied by stone peaks and debris slopes. Most of them have formed since late Pleistocene.2.Tertiary (especially early Tertiary )of Qinghai-Xizang Plateau, with tropic and subtropic climate, is favourable to development of karst. And then crust strongly changed, so that karst before Miocene was destroyed.3.In this region,paleokarst is mainly represented by cave and its deposits. Caves were mostly formed in middle Pleistocene,and a few of them in late Pleistocene (being at the edge of lake or the back fringe of low terraces along the rivers).4. Sinter has mainly formed in Holocene due to repidly changing of the karst spring in physical and chemical characters.