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RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 5, NO. 4, PAGES 255–272, doi:10.2205/2003ES000129, 2003

The origin of black shale-hosted Mn deposits in Paratethyan basins: Constraints from geological events at the Eocene/Oligocene boundary

I. M. Varentsov, N. G. Muzyliov, V. G. Nikolaev, and S. I. Stupin

Geological Institute of the Russian Academy of Sciences, Moscow, Russia


Abstract

[1]  The giant, Phanerozoic largest Mn deposits of southern Ukraine and Georgia and the Mn-rich strata of Mangyshlak, northeastern Bulgaria, northwestern Turkey, Hungary, and Slovakia were laid down synchronously at the base of the Early Oligocene interval. Their formation was controlled by an optimum combination of major geological events. The collision of Eurasia and the Indian subcontinent in terminal Eocene time boosted the generation of new sea floor at the crests of the global system of mid-ocean ridges with ensuing global transgression and a huge input of hydrothermal components (Mn, Fe, SiO2, Ca, CO2, etc.). Meanwhile in the Paratethys, Early Oligocene was a time of inception of and/or rapid subsidence in the marginal inland basins that stored black shales and vast amounts of dissolved Mn 2+. Shelf settings provided the milieu for extensive Mn deposition due to transgressive incursions of dense oceanic waters that displaced the Mn-rich anoxic ones.

Received 8 September 2003; published 13 November 2003.

Keywords: Paratethyan basins, Mn deposits, Eocene/Oligocene boundary, geological events.


RJES
Citation: Varentsov, I. M., N. G. Muzyliov, V. G. Nikolaev, and S. I. Stupin (2003), The origin of black shale-hosted Mn deposits in Paratethyan basins: Constraints from geological events at the Eocene/Oligocene boundary, Russ. J. Earth Sci., 5, No.4, 255-272, doi:10.2205/2003ES000129.

Copyright 2003 by the Russian Journal of Earth Sciences
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