Statistics of Trace Element Concentration in Oils, New Evidence for Naftidogenesis

Abstract

Trace elements (TE) composition of oils provides an important information on process of naftidogenesis. The TE composition of different caustobioliths (oils, coals, combustible and black shales) is compared with the chemical composition of organic matter and the upper, middle and the lower continental crust. The TE content of coals and shales correlates better with the chemical composition of the upper crust, whereas oil TE content from all oilbearing provinces (except Kamchatka) correlate better with the lower crust. Wherein, correlation betwen oil TE and organic matter is high, but often weaker than with the composition of the lower crust. Unlike all other oil provinces, for Kamchatka both oils and hydrothermal waters TE compositions better correlate with the upper or middle crust. The results are treated within the framework of the scheme of a flow-through nonequilibrium reactor, when the buried organic matter is the main source of oil hydrocarbons, but for massive oil formation, it is necessary to work out the sedimentary strata with an upward fluid flow bearing a TE mark of the depth of its formation. Under intense thermal regime of Kamchatka, dehydration processes occur at shallower depths, which explains the difference in the character of correlation.