MESOPROTEROZOIC MANTLE PLUME BENEATH THE NORTHERN PART OF THE SIBERIAN CRATON
D.P. Gladkochub1, T.V. Donskaya1, A.M. Mazukabzov1, S.A. Pisarevsky2,3, R.E. Ernst4,5,6, A.M. Stanevich1
1Institute of the Earth's Crust, Siberian Branch of the RAS, ul. Lermontova 128, Irkutsk, 664033, Russia
2Australian Research Council Centre of Excellence for Core to Crust Fluid Systems (CCFS) and the Institute for Geoscience Research (TIGeR), Department of Applied Geology, Curtin University, GPO Box U1987, Perth, WA 6845, Australia
3School of Earth and Environment, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
4Department of Earth Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
5Tomsk State University, pr. Lenina 36, Tomsk, 634050, Russia
6Ernst Geosciences, 43 Margrave Ave., Ottawa, ON K1T 3Y2, Canada
Keywords: Долериты, геохимия, мантийный плюм, мезопротерозой, Оленекский выступ, Сибирский кратон, суперконтинент Нуна (Колумбия), Dolerites, geochemistry, mantle plume, Mesoproterozoic, Olenek uplift, Siberian craton, Nuna supercontinent (Columbia)
Abstract
The study of the Mesoproterozoic (1473 ± 24 Ma) dolerites of the Olenek uplift of the Siberian craton basement has shown their petrologic and geochemical similarity to typical OIB produced with the participation of a mantle plume. The dolerites are characterized by variations in geochemical composition explained by different degrees of melting of the same source. A conclusion is drawn that the parental melts of the rocks were slightly modified by crustal contamination, as evidenced from their Nd isotope composition (εNd(T) = +0.6 to -0.8) and the presence of inherited zircons of four ages (2564, 2111, 2053, and 1865 Ma). Since the Siberian craton in the structure of the Nuna supercontinent (Columbia) was located relatively close to the Baltic continent and the Congo and Saõ Francisco cratons, we assume that the Early Mesoproterozoic mafic intrusions (1500-1470 Ma) of all these cratons belong to the same large igneous province (LIP). The province formation was related to the activity of superplume (or mantle hot field), which supplied mantle matter to the lithosphere basement. The superplume core was probably located beneath the northern part of the Siberian craton, where basites are compositionally most similar to the primary mantle source.
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