Analysis of Heavy Minerals in Sediments of XiningGuide Basin in Northeastern Margin of the Tibet Plateau in Cenozoic Era and Its Tectonic Evolution

Key words: 
• heavy mineral /
• basin evolution /
• basinrange coupling /
• XiningGuide basin /
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Abstract: The Cenozoic sediments of the XiningGuide basin, locates in the northeastern margin of the Tibetan plateau, recorded the uplift and deformation history of northeastern plateau. The detrital heavy mineral analysis is a sensitive tool to deciphering these records. Five heavy mineral stages of sedimentary evolution along this region have been revealed by the heavy minerals and tectonicsedimentary analysis: ① the earliest tectonic uplift phase between Paleocene and Early Eocene, ②steady stage of middle EoceneLate Oligocene, ③ late OligoceneEarly Miocene tectonic activity again, ④middle Miocene tectonic clam stage, ⑤stronger activity phases since Late Miocene. With the chlorite characteristics and the paleocurrent analysis，we suggest that the GuideXining was an uniform weakly flexural or rejuvenated Paleozoic foreland basin of the eastern Kunlun Mountain. The onset of deformation and rock uplift along the eastern part of the Laji Mountain, which was possibly effected by the surface uplift of the Tibetan plateau, divided the Guide and Xining basins. At about Late Miocene, the Laji Mountain began strongly deformation and surface uplift, and the Guide and Xining basins gradually recessed. These results provide a significant evidence to thoroughly understand the formation and evolution of the NE margin of Tibet.