LA ICP MS U-Pb ages of detrital zircons from Russia largest rivers: Implications for major granitoid events in Eurasia and global episodes of supercontinent formation

摘要

The paper presents LA ICP MS U-Pb age data on detrital zircons from sands of major Russian rivers: the Don, Volga, Ob', Yenisey and Amur. The obtained data are discussed in terms of major episodes of granitic magmatism, which are recorded in the continental blocks that form the modern Eurasian continent. Results are compared with published igneous and detrital zircon age data obtained from parental and sedimentary rocks of the river basins under consideration and worldwide. The U-Pb age results allowed us to confirm (ⅰ) the episodic character of continent formation; (ⅱ) the Neoarchean global magmatic event and, possibly, formation of the Kenorland supercontinent; (ⅲ) the global episode of crust formation at 2.0-1.8 Ga, which formed the Columbia supercontinent; (ⅳ) the breakup of Columbia at 1.3-1.2 Ga; (ⅴ) the major period of Phanerozoic crustal growth in Central Asia which is likely to be a result of the Altaid orogeny. On the other hand, our data did not unambiguously confirm previous idea about the global character of the Grenvillian and Pan-African orogenies as a result of the assembly of Rodinia and Gondwana, respectively. The "Rodinia" peak is not observed in the histograms of the Ob', Yenisey and Amur, whereas the "Gondwana" signature is not obvious in the histograms of the Don, Volga and Amur. Of special interest are the 2.7-2.5 Ga and 2.0-1.7 Ga peaks in the Ob' zircon age spectrum in spite of the absence of so far identified Archean and Paleoproterozoic parental rocks in the Ob' catchment area. The obtained age spectra were joined into three groups based on statistics: Baltica (Don and Volga), Siberia (Ob' and Yenisey) and East Asia (Amur). For future reconstructions we suggest to include all the available results on Don and Volga rivers into a North America-Baltica Group corresponding to Laurentia-derived continental blocks, and to consider a Siberia Group (Siberian Craton; Ob', Yenisey, Lena, Indigirka rivers) and an East Asia Group (North and South China cratonic blocks; Amur, Yellow, Yangtze and Mekong rivers).