Naslov
O starosti i nalazima fosilnih riba u kredi Jadranskog pojasa
(About the age and the localities of the Creataceous fishes in the Adriatic zone)

Autori
Radovčić, Jakov

Izvornik
Geološki vjesnik (0016-7924) 25 (1973); 321-326

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
fosilne ribe, kreda, Jadranski pojas
(fosil fish, Creataceous, Adriatic zone)

Sažetak
The slab limestones of the Cretaceous complex of the Adriatic zone, in which fossil fishes have been found, are widespread. This facies, with special paleogeographical and sedimental characteristics, occurs in the large, shallow, carbonate sea-basin where pseudo-reef rudist limestones have had a dominant development (Polšak, 1965). The areas between the reefs get the qualities of closed lagoons with the reductive characteristics because of the vertical oscillations which are constantly present, where the limestones of the pelagic type, most frequently poor in fossils, leave sediments here in a shallower and there in a deeper sea. This regime, with similar lithofacial and paleontological characteristics, maintained from the Tithonian (Gorjanović-Kramberger, 1895) till the Senonian (Herak, 1959 ; 1960 ; Pleničar 1960 ; Polšak, 1965, and others) and it can be asserted that the strata with fossil fishes occur in a high vertical succession. This Gorjanović- Kramberger's opinion (1895) can be actualized. It remains that the most frequent traces of the fishes in slab limestones are of the Cenomanian, respectively Turonian age (see the Fig. 1.). It is evident that fossil fishes are located only in some lenses of slab limestones and the great number of the found specimens, with enough species and genera represented, really impresses. Taking into consideration that Creataceous fishes in these fields have lived in lagoons or in some rather closed bays, which have suddenly assumed the reductive characteristics of the surrounding, where even bitumen has sporadically left sediments the idea of probable taphocenoses is imposed ; they correspond to bitumen sedimenting. Because of the abrupt changes of the ecological conditions, unfavourable for the development of organisms, the fishes have suddenly disappeared. Considering the character of sedimentation, the possibility of dead organisms to fossilize has existed.

Izvorni jezik
Hrvatski

Znanstvena područja
Geologija

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