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STRATI 2013 pp 1135-1138 | Cite as

The Turonian–Coniacian Boundary in Western Georgia Based on Planktonic Foraminifera

  • Khatuna MikadzeEmail author
Conference paper
Part of the Springer Geology book series (SPRINGERGEOL)

Abstract

Upper Cretaceous sediments are widespread in western Georgia (the Gagra–Java zone). Upper Turonian–lower Coniacian deposits in the western part of the Abkhazia–Racha facies type (the basins of the Chanis–tskali and Ochkhomuri rivers) are represented mainly by firm carbonate rocks, in which the Gumurishsk suite is exposed. Within the Odishi–Okriba facies type, terrigenous–volcanic rocks are significant, and were formed within the general background of carbonate sedimentation. The layers are enriched with a tuffaceous material, and are found with white and red calcareous rocks of the Mtavari Suite (K2t3–K2st). This suite is composed of brick-red, brown, or yellowish-grey basalts and porphyritic effusive rocks, with interlayers of calcareous deposits and sandstones. In most previous studies of the stratigraphy of the Abkhazia–Racha and Odishi–Okriba facies types, the focus was placed on macrofauna. On the basis of the present detailed examination of planktonic foraminifers in the Abkhazia–Racha and Odishi–Okriba facies types, the Marginotruncana coronata Zone is defined at the beginning of the Coniacian. The appearance of the species Marginotruncana coronata identifies the lower boundary of the Coniacian.

Keywords

Facies Foraminifera Georgia Mtavari Turonian Coniacian 

References

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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Georgian National MuseumInstitute of PaleobiologyTbilisiGeorgia

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