Proterozoic supercontinental restorations: Constraints fromprovenance studies of Mesoproterozoic to Cambrian clastic rocks,eastern Siberian Craton

• Main Author: Худолей, Андрей Константинович
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2015
• Subjects: Taimyr
• Online Access: http://hdl.handle.net/11701/19267

The Mesoproterozoic–Neoproterozoic sedimentary succession of the eastern part of the Siberian Cratonconsists of several unconformity-bounded, kilometer-scale siliciclastic-carbonate cycles. The overlyingLower Cambrian rocks are often compositionally similar to the uppermost units of the Neoproterozoicsuccession.Twenty-nine samples were collected for U–Pb detrital zircon study and 27 samples were analyzedfor whole-rock Sm–Nd isotopes. In total, 1491 detrital zircon grains were dated and 1148 grains wereselected for provenance interpretation. Samples from the Uchur and Aimchan groups only contain detri-tal zircons of Paleoproterozoic and Archean age. Samples from the Kerpyl Group located on the SiberianCraton contain Paleoproterozoic and Archean grains as well, but samples from the Kerpyl Group in theSette-Daban Ridge have significant numbers of Mesoproterozoic detrital zircons. Mesoproterozoic detri-tal zircons predominate in samples from the Uy Group. In the northern part of the study area, samplesfrom the uppermost Neoproterozoic and Lower Cambrian strata contain numerous ca. 790–590 Ma detri-tal zircons, whereas in the southern part of the study area only Paleoproterozoic and Archean grains havebeen found. The whole-rock Sm–Nd isotopic values of clastic rocks show that most samples have isotopicsignatures typical for the Siberian Craton basement, whereas some samples from the Kerpyl Group andyounger rock units have isotopic signatures typical of the Grenville Orogen.Most of the Archean and Paleoproterozoic detrital zircons were eroded from the basement of theSiberian Craton, although some ca. 2080–2030 Ma detrital zircons are likely to have a non-Siberian pro-venance. However, rocks younger than ca. 1700 Ma are not known in the Siberian Craton basement andall Mesoproterozoic and younger grains must therefore have a non-Siberian provenance.The detrital zircon age distributions and whole-rock Nd isotopic signatures of many samples fromthe Kerpyl Group and younger units are very close to those of the Grenville Orogen in North America, suggesting that erosion of the latter contributed to clastic deposition along the Siberian margin. Three pale-ocontinental restorations proposed by Sears and Price (1978, 2003), Rainbird et al. (1998) and Pisarevskyand Natapov (2003) are invoked to explain the occurrence of Grenville-age detrital zircons in the Siberiansedimentary succession. The provenance of ca. 790–590 Ma detrital zircons is most likely to be locatedwithin the Central Taimyr accretionary belt formed along the northern margin of the Siberian Craton inthe Neoproterozoic.