in Jurassic and Cretaceous Stratigraphy

Earth Science Frontiers, Vol. 17, Special Issue, Aug. 2010 ISSN 1005-2321
266
Paleogeography of the Bathonian Basins of Georgia
Iver Tsereteli, Tamaz Lominadze
Institute of Paleobiology, Niagvari str.4, 0108 Tbilisi, Georgia (E-mail: lominadzetamaz@yahoo.com)
In the history of the geological development of
Georgia, the Bathonian period appears particularly
interesting as it was the time of considerable trans-
formations in the tectonic as well as the paleo-
zoogeographic sphere. The Bathonian formations on
the territory of Georgia (Fig.1) are represented by flysh,
flysh-like, epicontinental and lake-lagoon deposits and
are bound with the Fold system of the Greater Caucasus
(I), South Caucasian intermontane area (II) and the Fold
system of the Lesser Caucasus (III).
There are many works giving a detailed discription
of the geological conditions of the Bathonian basins
formation process as well as the paleogeographical
issues ( Dzotsenidze and Skhirtladz, 1961; Rostovtsev,
1978; Topchischvili et al., 2006).
A.Tsagareli and M.Eristavi (1977) were among
the first researchers studying the paleogeography and
paleozoogeography of the Caucasus in the Mesozoic
period. On the bases of the paleontological material
analysis the authors came to the conclusion that durig
the Mesozoic period the migration routs and the fauna
New paleontological materials accumulated in
recent years allows for bringing some alternations into
existing image of paleozoogeography of the Caucasusin
the Bathonian period.
The strong Bajocian – Bathonian regression in the
South Caucasus resulted in the emergence of a vast land
mass with small sea basins. They connected to the
neighbouring seas but it is difficult to trace the con-
nection precisely.
On the territory of Georgia four separate sea
basins were formed (Fig.1): 1. Flysh-like (Novo-
composition in the Caucasus were considerably
changing and that the Caucasus should be researched as
an independent paleozoogeographical area. Later on
Rostovtsev K. (1978) made a zoogeographical division
of the Caucasian seas and singled out the North
Caucasian, South Caucasian, Lesser Caucasian and
Nakhitchevanian zoogeographical provinces in the
Middle Jurassic period. According to the author’s data,
in the Late Bajosian period the representatives of the
Mideuropean and Mediterranean ammonites were
commonly occurred in the Caucasian province. As to
the Bathonian fauna, only the ammonite fauna of the
Lesser Caucasus is discussed there. In that work the
Bathonian zoogeographical situation and the cor-
responding fauna of the ammonites of the South
Caucasian province were not discussed. Most probably
the author was not acquainted with the description of
representatives of families Oecotraustes, Cadomites,
Sphaeroceras, Morphoceras, Ebrayiceras from the
Lessser Caucasian province (Zesashvili et al., 1977).
Fig.1 Outlines of the Bathonian basins of Georgia
rossiysk-Toapse Zone), 2. Flysh (Chkhalta-Laila,
Mectia-Tianeti and Kazbegi-Lagodekhi Zones), 3.
Epicontinental (Gagra-Java Zone: in Abkhasia - the
basin of Bitaga, Gega and others; in Racha– the basin of
the Rioni-Kvirila rivers) and in South -East Georgia
(the Lesser Caucasus – Locki-Karabakh Zone) and 4.
Lake–lagoon (the southern periphery of the Gagra-Java
Zone of the Fold system of the Greater Caucasus -
Bzibi, Magana, Tkvartcheli) and in the Central Zone of
the uplift of the South Caucasian intermontane area:
the coal-bearing basins of Kutaisi, Gelati, Tkibuli,