Geochronology and paleomagnetism of mafic igneous rocks in the Olenek Uplift, northern Siberia: Implications for Mesoproterozoic supercontinents and paleogeography

Michael T.D Wingate,Sergei A Pisarevsky,Dmitry P Gladkochub,Tatiana V Donskaya,Konstantine M Konstantinov,Anatoly M Mazukabzov,Arkady M Stanevich

doi:10.1016/j.precamres.2009.01.004

Abstract

We present a new, reliably dated Mesoproterozoic paleopole for Siberia, based on a combined geochronological and paleomagnetic study of mafic rocks within the Mesoproterozoic Sololi Group of the Olenek Uplift in northern Siberia. Ion microprobe (SHRIMP) U–Pb analysis yields crystallisation ages of 2036 ± 11 Ma for zircon from a basement granite and 1473 ± 24 Ma for baddeleyite from a large dolerite sill within the Kyutingde Formation. The baddeleyite result indicates that the lower Sololi Group is significantly older than was suggested by previous K–Ar results. Paleomagnetic analysis of the dolerite sill and related mafic intrusive rocks yields a paleopole at 33.6°N, 253.1°E, A 95 = 10.4°. A positive baked-contact test between the Kyutingde sill and sedimentary country rocks shows that the magnetisation is primary. Comparison of this paleopole with coeval results for Laurentia provides a revised reconstruction between Siberia and Laurentia, and implies that these two continents were parts of a single Mesoproterozoic supercontinent since at least 1473 Ma. We argue that Siberia, Laurentia, and Baltica belonged to the same supercontinent between 1473 Ma and mid-Neoproterozoic time.

Highlights

The Siberian Craton is the most ancient structure in northeastern Eurasia
In the course of its evolution, this craton was repeatedly involved in various continental agglomera‐ tions and separated from them in the course of super‐ continental breakups. Imprints of these events are found in heterochronous basite magmatism features, including the Late Precambrian dyke swarms formed during the breakup of Rodinia and reflecting, at least, the Neoproterozoic age of the eastern and southern craton margins [Gladkochub et al, 2010a, 2010b]
In the course of its evolution, the Siberian Craton as a part of the large continental agglomerations was repeatedly involved in the continental breakup processes

Summary

Introduction

The Siberian Craton is the most ancient structure in northeastern Eurasia. Its lithosphere stabilized in the Paleoproterozoic, around 1.9 GA B.P. [Rosen et al, 2006]. In the course of its evolution, this craton was repeatedly involved in various continental agglomera‐ tions and separated from them in the course of super‐ continental breakups. Imprints of these events are found in heterochronous basite magmatism features, including the Late Precambrian dyke swarms formed during the breakup of Rodinia and reflecting, at least, the Neoproterozoic age of the eastern and southern craton margins [Gladkochub et al, 2010a, 2010b]. In the southern areas of the craton, dolerite dikes intruded into the Paleoproterozoic granitoides and granite‐gneiss rock complexes within the Urik‐Iya graben, Biryusa and Goloustnoe edges of the craton basement [Gladkochub et al, 2007]

Methods

Discussion

Conclusion