RECONSTRUCTION OF THE AREAS OF "SUBSURFACE CHLOROPHYLL MAXIMUM " IN THE ANABAR-LENA SEA (LATE JURASSIC - EARLY CRETACEOUS) OF THE NORTHERN FRAME OF THE SIBERIAN CONTINENT
V.A. Kashirtsev, B.L .Nikitenko, E.B. Peshchevitskaya
Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Siberian platform, Upper Jurassic, organic geochemistry, hydrocarbon biomarkers, deep chlorophyll maximum (DCM).
Abstract
In the north of the Siberian Platform, deep chlorophyll maximum (DCM) regions have been reconstructed in Upper Jurassic and Berriasian sedimentary formation based on geological and geochemical features of organic matter composition. These reconstructions are based on the results of chromatograph mass-spectrometry studies of the individual composition of chloroform extraction bitumen, primarily the exceptionally high concentrations of isoprenoid hydrocarbons (pristane and phytane), the content of which is several times higher than that of adjacent (nearly eluting) normal alkanes. In the aromatic fractions of bitumen, DCM is identified by the unusually high contents of chromanes with an "isoprenoid tail," which arose as a result of diagenetic condensation reaction between chlorophyll and phenols. The spatial location of the DCM regions is determined by the coastline of the Anabar-Lena Sea and the Siberian paleocontinent.
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