Neoproterozoic Orogeny along the margins of Siberia

Abstract

The Siberian Craton is bounded by fold-and-thrust belts involving Neoproterozoic (locally Mesoproterozoic) complexes on the southern (Baikal-Vitim), western (Yenisey Ridge and Turukhansk-Igarka), northern (Taimyr), and eastern (Verkhoyansk) sides. This paper focuses on the geological structure and evolution of these formations. Previous and new geochronological data show that passive continental margins existed around most of the Siberian Craton during the early Neoproterozoic and possibly the late Mesoproterozoic. Between about 850–760 Ma, the southern, western and northern passive margins of the Siberian Craton were transformed into active margins. Middle-late Neoproterozoic island arcs and ophiolites were formed between c. 750–650 Ma along these margins; they are inferred to have been obducted onto the Siberian continental margin at c. 600 Ma, prior to late Vendian deposition. New ion microprobe U-Pb ages of ophiolitic rocks from Taimyr’s Central domain are presented. The Neoproterozoic record in the Cretaceous Verkhoyansk fold-and-thrust belt indicates that the eastern part of the Siberian Craton remained a passive continental margin during the Neoproterozoic and Palaeozoic. Baltica-Siberia relationships are also discussed.

U-Pb and geochemical evidence for a Cryogenian magmatic arc in central Novaya Zemlya, Arctic Russia

“…The Enganepe ophiolite, now part of the Uralian orogen, developed at 670 Ma in an oceanic island arc setting and was then thrust on Baltica during the Timanian convergence (Scarrow et al, 2001). The events at 716-704 Ma also correlate with arc magmatism recorded on different margins of the Siberian craton (Amelin et al, 1996;Vernikovsky et al, 2003Vernikovsky et al, , 2004. In more general terms, it also fits with the protracted activity recorded in the peri-Gondwanan realm.…”

“…The events at 716–704 Ma also correlate with arc magmatism recorded on different margins of the Siberian craton (Amelin et al. , 1996; Vernikovsky et al. , 2003, 2004).…”

Riphean basins of the central and western Siberian Platform

“…These observations suggest that the Riphean structural unit of the platform was not affected by contemporaneous deformations but was rather deformed mainly during later tectonic activity in the region. This activity coincides with the Baikalian orogeny (the end of Riphean) that resulted from the collision processes along the western and southern margins of the platform (Vernikovsky et al, 2003(Vernikovsky et al, , 2004Nemerov and Stanevich, 2001). Additionally, the north-western periphery of the platform (Turukhansk Uplift) experienced several more stages of fold-thrust deformations.…”

Results of the U-Pb age of detrital zircons from Upper Proterozoic deposits of the eastern slope of the Anabar uplift

“…The eastern orienta tion of paleoflows contradicts the idea of the supply of zircons from the eastern margin of the Siberian Plat form. The most probable provenance area could be the Taimyr Orogen, where metarhyolites (627 ± 7 Ma) and metamorphic events (625-575 Ma), close in age, were established (Vernikovsky et al, 1997;Vernikovsky et al, 2004). The igneous complexes similar in age are known in the southern and southwestern folded fram ing of the Siberian Platform (Vernikovsky et al, 2004;Vernikovsky and Vernikovskaya, 2006;Rytsk et al, 2007), but in the Late Vendian, the greater part of the Siberian platform was flooded with water and the transfer of the detrital material through a sea basin over a considerable distance seems unlikely.…”