Trace elements composition of detrital zircon of archean age from jatulian terrigenous rocks of Fennoscandia

Smolkin V. F., Skublov S. G., Vetrin V. R.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2020. V. 149. N 6. P. 85-100

https://doi.org/10.31857/S086960552006012X

Language: Russian

Abstract

Previously, detrital zircon with an age of 3.65–3.87 Ga was found in the Jatulian terrigenous rocks of the eastern part of the Fennoscandian Shield (Karelian and Kola regions) (Kozhevnikov et al., 2010; Smolkin et al., 2011, 2019). Rocks of the similar age in the underlying Sumian-Sariolian complexes and the Archean basement were not known. With the aim of establishing the field of demolition and the composition of its sources, for the first time there was studied geochemical composition (rare earth and trace elements) of detrital zircon from Jatulian red-colored gravelites of the Luchlompo Formation of the Pechenga structure, Volomskaya syncline quartzites, and cement conglomerates in the western part of the Onega depression, located at a considerable distance from each other. The age of detrital zircon grains ranges mainly from 2.70–3.23 Ga. It is established that the predominant part of them is represented by the magmatic type. Grains and rims of zonal grains with the minimum age (2.70–2.72 Ga) are classified as metamorphic. There is also a “porous” zircon that has experienced a fluid effect. The principal sources for magma-type zircon were tonalite, trondhjemite gneisses, and acidic granulites that were widely developed in the environment of the studied structures and detected in the lower part of the Kola Superdeep, as well as gneisses and amphibolites of the Vodlozersky Block. The source of detrital zircon with an age of 3.65–3.87 Ga was the trondhjemite gneisess of Siurua, located in Northern Finland. Their erosion and transfer of zircon took place during the period of 2.2–2.1 Ga, along the Western edge of the basin of the Svecofennian-Pre-Labrador Paleoocean, which existed at the initial stage of the formation of the supercontinent Columbia.

Keywords: Kola region, Karelian region, Paleoproterozoic, Jatulian, Paleoarchean, Eoarchean, Pechenga structure, Volomskaya syncline, Onega depression, detritic zircon, geochronology, trace and rare-earth elements