First data on methylhopanes in Lower Cambrian organic matter of the Siberian platform

Hopane hydrocarbons of bitumoids from the organic matter of the Lower Cambrian Sinyaya and Kutorgina formations on the northern slope of the Aldan anteclise were studied using chromatography?mass spectrometry. Methylhopanes were found for the first time in autochthonous bitumoids of scattered organic matter from Cambrian sedimentary basins in Siberia. The biological sources of these molecules, along with the features of geochemistry, sedimentation conditions, diagenesis, and degree of maturity of methylhopanecontaining organic matter are considered. Methylhopanes were recommended to be used jointly with other biomarkers of the Sinyaya formation rocks enriched in organic matter to determine the possible source of naphthides in the southeastern part of the Siberian platform.