Ultralight Oxygen in Corundum-Bearing Rocks of North Karelia, Russia, as a Result of Isotope Separation by Thermal Diffusion (Soret Effect) in Endogenous Fluid Flow

摘要

Helium and argon isotopes in fluid inclusions in minerals of corundum bearing rocks with anomalous light oxygen of the Khitoostrov (North Karelia, Russia) were studied. It was found that atmospheric noble gas component is missing. Therefore, all previously proposed models of participation in the fluid surface ice meltwater are not valid. Proposed and justified endogenous mechanism of isotope fractionation of oxygen and other chemical elements by the mechanism of thermal diffusion. Geologically justified existence of the cascading effect for a number of the separation thermodiffusion cells, which lead to significant isotope effects. Cascading is realized due to the “fluid pump”, in which role are acting amphibolized gabbro in the contact with corundum metasomatites. It is assumed that the mechanism is not specific for the case corundum metasomatic rocks, which are a special case of manifestation of such a scenario in processes involving endogenous fluid flows.