TRENDS IN THE DISTRIBUTION OF OIL AND GAS DEPOSITS IN THE SOUTH CASPIAN DEPRESSION
Title:
TRENDS IN THE DISTRIBUTION OF OIL AND GAS DEPOSITS IN THE SOUTH CASPIAN DEPRESSION
Author:
Gorin, V. A.
Appeared in:
International geology review
Paging:
Volume 6 (1964) nr. 1 pages 85-90
Year:
1964-01
Contents:
The very rich oil fields of Azerbaydzhan and Turkmenia lie in the northern half of the South Caspian depression. The structure in Azerbayzhan involves the most deeply depressed part of the depression and the Kura and Transcaspian marginal regions, the latter two with the notable Azerbaydzhan and Turkmenian tectonic steps. These steps, related to the shallows around the submerged parts of the Caucasus and Kopet Dag mountain structures, are the result of downwarping along deep faults at the edge of the depression. Evidence of the faults is periodic eruptions of mud volcanoes along the line of the faults. Records over the last 150 years show a cycle of activity every 50-60 years — 1852, 1886, and 1952. Cyclic behavior is attributed to periodic uplifting of the Main Range in the Caucasus. Latitudinal strike of Apsheron Peninsula coincides with direction of deep regional folding and associated deep faults. Volcanoes represent these faults above Upper Tertiary cover. Numerous blocks of Tertiary and Mesozoic strata, in part fossil-bearing, are "among those brought up with the lava in the eruption of petroleum (mud) volcanoes. " Petroleum pipes are believed to represent migration of first gas, then liquid, and finally a mixture of petroleum and sand. Comparison is drawn with Trinidad and its volcanoes and petroleum pipes and dikes. Deep faults in Apsheron and adjacent areas illustrate relation between Mesozoic and Tertiary structural stages. Deep faults in the Mesozoic, which may extend into pre-Oligocene strata, determined positions of buried ridges. Inherited later faults are responsible for more complex system of narrow blocks and elongated folds. Prolonged structural development affected Mesozoic and Cenozoic facies and account for facies changes in thick productive middle Miocene series. W. D. Lowry
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