Classification of the asphalts and their source rock from the Dead Sea Basin (Israel): the asphaltene/kerogen vanadyl porphyrins

Abstract

The asphaltenes of the asphalts from the Dead Sea Basin were examined for the occurrence of vanadyl porphyrins. These examinations demonstrate that the asphalts fall into two broad class types: one which exhibits a relatively high vanadyl porphyrins content ( GT 300ppm), and the other characterized with no vanadyl porphyrins ( LT 10 ppm). It is concluded that these asphalts belong to two distinct types and have separate origins. The kerogens isolated from the petroleum-source rock of the Dead Sea Basin were also analyzed. Two genetic types of kerogen appeared to exist: a marine one highly enriched with these pigments and a terrestrial one with no vanadyl porphyrins. For comparison, the asphaltenes of typical asphaltic crude oils from Western Venezuela and kerogen from their La Luna source rock were also examined. Previous detailed geochemical studies indicated that the La Luna kerogen is derived from marine organic matter source. These materials have higher concentrations of vanadyl porphyrins than the Dead Sea asphaltenes and kerogens are enriched with these compounds. Our results strengthen the potential of vanadyl porphyrins of both petroleum asphaltenes and source-rock kerogen for use in genetic and correlation studies. (C) 1998 Elsevier Science Ltd. AII rights reserved.