Australia: The Land Where Time Began

A biography of the Australian continent 

Siberia and Laurentia – Long-Lived Connection between Southern Siberia and Northern Laurentia in the Proterozoic

Nuna-Columbia (1.7-1.3 Ga) and Rodinia 1.1- 0.7 Ga) are supercontinents that have been proposed to have existed in the Precambrian. It is poorly known how the crustal blocks were arranged within these supercontinents. An important tool for the reconstruction of supercontinents are the magmatic outpourings and intrusions, that are dominantly basaltic, that cover areas of up to millions of square kilometres, that are termed Large Igneous Provinces, which typically accompany the breakup, or abortive breakup, of (super) continents. In this paper Ernst et al. present the results of their study that focused on the Large Igneous Province record from Siberia and Laurentia, the reconstructions of the relative positions of these landmasses in Nuna-Columbia and Rodinia which is highly controversial. Precise geochronology (9 U-Pb and 6 Ar-Ar ages) on dolerite dykes and sills, as well as existing dates from the literature, that constrain the emplacement of Large Igneous Province magmatism in southern Siberia and northern Laurentia between 1.9 Ga and 700 Ma. There are 4 robust age matches between the continents 1.87, 1.75, 1.35 Ga and 700 Ma, as well as several additional age correlations which are approximate, indicating that it is probable that southern Siberia and northern Laurentia were near neighbours for this interval of 1.2 Gyr. A framework for evaluating the shared geological, tectonic and metallogenic histories of these continental blocks has been provided by these reconstructions.

Sources & Further reading

Ernst, R. E., M. A. Hamilton, U. Soderlund, J. A. Hanes, D. P. Gladkochub, A. V. Okrugin, T. Kolotilina, A. S. Mekhonoshin, W. Bleeker, A. N. LeCheminant, K. L. Buchan, K. R. Chamberlain and A. N. Didenko (2016). "Long-lived connection between southern Siberia and northern Laurentia in the Proterozoic." Nature Geosci 9(6): 464-469.