"The discovery of komatiites-ultramafic volcanic rocks-was one of the most important petrological advances of this centry. Not only are komatiites economically important as host rocks to many nickel deposits, but they are also of great scientific interest since they provide unique information on the early history of of the Earth`s crust and upper mantle...." N.T.Arndt, E.G.Nisbet (Komatiites // London, 1982,526p.
Lake Sovdozero, Central Karelia (Sovdozero structure, Vedlozero - Segozero greenstone belt)
The present paper is concerned with one of the aspects of the geological and geochemical study of komatiitic volcanics in the eastern Fennoscandian Shield in Karelia, on the Kola Peninsula and in eastern Finland. It is well-known that komatiites are formed at high degrees of mantle substrate melting. Therefore, their geochemical characteristics most clearly reflect the composition of mantle sources, and the temperature characteristics of melts can be used to determine a thermal regime at the magma-generating levels of the upper mantle.
- to reconstruct the columns of some greenstone structures and to pin-point the position of komatiites in them;
- to study facies, textural and structural rock varieties.
- to characterize volcanics geochemically;
- to determine the primary composition of ejected magma;
- to estimate melt ejection and magma generation temperatures;
- to characterize the Archean and Proterozoic evolution of temperature regimes.
If you are interested, We spend one and two day excursions.
[The goal of the excursion is to demonstrate a section through the Upper Archean komatiites and basalts of the Hautavaara structure].
[The purpose of excursion is to demonstrate Upper Archean rocks (komatiites, tholeites,medium volcanics as well as chemical and terrigenous rocks), stratigraphic contacs between Archean and Proterozoic terranes and granitoid deposits].
[The purpose of the excursion is to show Upper Archean komatiite-basaltic volcanics in the Palaselg Greenstone structure].
Separately in the plan of trip visiting a "Kizhi" monument of wooden architecture can be included.
3. Layered flows
7. Mantle sources
9. Researcher (Sergei Svetov)