关键词: 青海湖, 地质背景, 新构造, 差异隆升

Abstract: The Qinghai Lake area is situated at the juncture of 3 tectonic units and several deep faults, so tectonic deformafion is exfensive there. Fault depression took place in Pliocene and the Qinghai Lake formed in Middle Pleistocene. The Lake basin can be divided into 3 horsts and 3 second-order fault basins. The formation and evolution of the Qinghai Lake had been mainly controlled by removement of south marginal large fault belt of Middle Qilian block, ZhongwulongshanQinghainanshan large fault belt and HeimaheDari large fault belt, the movement of faults with strikes in NWW, NW, NNW, SN and NE, and regional differential uplifting as well. Its formation and evolution had close relationship with uplifting of Qinghai-Tibet plateau, especially with negative inversion structure formed by change of stress field in Middle Pleistocne. Since the formation of Middle Miocene leveling plane, the neotectonism and the formation and evolution process of the Qinghai Lake are characterized by obvious pulsation. Since Middle Miocene, neotectonic activities over Qinghai Lake area can be divided into 5 periods, and the formation and evolution of the Qinghai Lake can be divided into 9 stages.

Key words: Qinhai Lake, Tectonic setting, Neotectonism, Differential uplifting