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Yuri Galant, Independent Researcher (Israel)
Alfred Geptner, Geological Institute Russian Academy of Science (Russian Federation)
Yuri Pikovskii, Moscow State University (Russian Federation)
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A large amount of the oil-gas bearing basins is connected with the World Rifts Systems. At the same time one can observe intensive upwards flows of hydrocarbons from the recent rift systems. There is a reason to suggest that oil and gas-fields in the rift systems were formed by those gas and fluid upflow. Naturally enough that the Iceland and Israel (Dead Sea) rift systems are to be considered studying this problem. The polycyclic aromatic hydrocarbons (PAH) have been studied in both rifts. It was revealed that these compounds may serve as an indicator of geochemical environment in studying distribution, and migration, and time of hydrocarbons generation and accumulation. The Skjálfandi and Öxarfjörður sedimentary basins have been developed in the NE?SW spreading zone, which crosses Iceland, and the Tjörnes fracture zone. Both have substantial sedimentary successions composed of sediments having probably similar composition. At the Öxarfjörður and Skjálfandi sedimentary basins there are the gas and fluid emanations containing hydrocarbons, including PAH and high-molecular hydrocarbons. In fault zones hot water discharging from springs and wells is characterized by presence of a variety of unsubstituted PAH species. Several natural PAH associations were revealed as typical for the modern hydrothermal activity in the rift zone of Iceland: phenanthrene, benzofluorene, chrysene and pyrene. At the surface in modern marine and lagoon sediments perylene is widespread and may even be treated as a separate very characteristic compound. Pyrene?naphthalene association predominates at the flank zone of the geothermal fields and characterized the Holocene/Pleistocene sedimentary succession. Northern part of Dead Sea Rift was filled by Mesozoic and Cenozoic deposits and basalts of Neogene-Recent age covering vast areas. Four types of PAH associations were identified in volcanic rocks and minerals: 1) naphthalene 2) naphthalene-pyrene 3) naphthalene- coronene 4) association of PAH homologous. It is suggested that the first and the second associations can be considered as the traces of the gas migration, the 3rd can be identifying as a hydrothermal migration of the heavy hydrocarbon molecules, and the 4th association shows a migration of the petroleum compounds. So above mention facts show existence a hydrocarbon potential on depth. The obtained data allowing elucidate hydrocarbon potentials of modern and old rift zones.
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