Geological and geochronological evidence for the Precambrian evolution of the Tarim Craton and surrounding continental fragments

Abstract

The Tarim Craton, located in northwestern China, is one of the largest cratons in China. Based on the tectonic evolution and stratigraphic sequence, the craton can be subdivided into an older, pre-Nanhua metamorphic basement and a younger sedimentary cover consisting of strata from the Nanhua System [middle Neoproterozoic, according to Stratigraphy Committee of China, 2001. China Stratigraphic Guide and Exposition on China Stratigraphic Guide (revised Edition), Geological Publishing House, Beijing, pp. 1–59 (in Chinese) or Cryogenian by the International Stratigraphic Chart, Gradstein, F.M., et al., 2004. A Geologic Time Scale 2004. Cambridge University Press, 589 pp] to Phanerozoic ones. Archaean gneisses are exposed only on the eastern and northern margins of the craton [Gao, Z.J., Chen, J.B., Lu, S.N., Peng, C.W., Qin, Z.Y., 1993. The Precambrian Geology in Northern Xinjiang. Precambrian Geology No.6, Geological Publishing House, Beijing, pp. 1–171 (in Chinese); Cheng, Y.Q., 1994. Outline of Regional Geology in China. Geological 615 Publishing House, Beijing, pp. 1–517 (in Chinese)]. However, Palaeoproterozoic high-grade metamorphic rocks and Mesoproterozoic lower-grade metamorphic strata are widespread. The Nanhua (Cryogenian) and Sinian (Ediacaran) sequences form a typical sedimentary cover, in which glacial deposits are well preserved. Late Mesoproterozoic to middle Neoproterozoic tectono-thermal events can be subdivided into two major periods. The first period of events (1.05–0.90 Ga) is similar to that of the Yangtze Craton and reflects a compressional regime corresponding to the final assembly of Rodinia. The second period of events lasted from 0.82 Ga to 0.74 Ga and reflects a rifting process related to break-up of this supercontinent. Based on new geological and geochronological data, the relationship between the Tarim Craton and other continental fragments is also discussed.