Naslov
Geodynamic significance of the Upper Cretaceous and Paleogene carbonate clastics of the External Dinarides

Autori
Jelaska, Vladimir ; Gušić, Ivan ; Cvetko Tešović, Blanka ; Bucković, Damir ; Ćosović, Vlasta

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
23nd IAS Meeting of Sedimentology, Coimbra, September 15-17, 2004 : Abstracts book / Pena dos Reis, Rui ; Callapez, Pedro ; Dinis, Pedro - Coimbra : International Association of Sedimentologists (IAS), 2004, 153-153

Skup
23nd IAS Meeting of Sedimentology

Mjesto i datum
Coimbra, Portugal, 15.09.2004. - 17.09.2004

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Upper Cretaceous; Paleogene; carbonate clastics; External Dinarides

Sažetak
From the beginning of the Upper Cretaceous, the hitherto uniform depositional environment of the Adriatic-Dinaric carbonate platform began to differentiate. Starting from the Early Cenomanian, intensive tectonic movements marked the initial platform disintegration phase, which produced the environmental differentiation. Advanced collision processes, that took place at the north-northwestern platform area, initiated the tilting of the entire platform, causing uplifts in what is today northern Adriatic Sea, as well as simultaneous subsidence at southern Adriatic Sea area. The tilting of the platform was accompanied by disintegration processes, which produced the intraplatform troughs. Depositional processes that took place within one of these troughs can be observed within the sedimentary signatures on the north Dalmatian islands ; Premuda, Ist and Dugi otok. Recent investigations showed that this particular trough was fed by huge amount of allochthonous shallow-water carbonate detritus that was shed from its border areas during the Late Cretaceous-Early Paleogene. This is also confirmed by the offshore data from the deep wells in the Adriatic Sea. Recently, very similar relations were observed in the Biokovo and Mosor Mts. areas. However, mutual relations between these troughs including their precise locations, geometry, possible connections, and their geochronological framing as well as the time of the strongest synsedimentary tectonic events, are still open to debate and are the main goals of this paper. In order to attend these goals, we undertook complex stratigraphic investigations, including the analysis of skeletal and non-skeletal allochems presented within the allochthonous carbonates. As the synsedimentary tectonic movements are responsible for the formation of intraplatform troughs, the stratigraphic framing of these Cretaceous palaeotectonic signatures is the key to understand the geodynamic evolution of the Biokovo and Mosor Mts. areas. Because the intraplatform troughs are always physiographically limited, anoxic conditions will have been preferentially established. In addition, the gradual, tectonically controlled, subsidence is an essential factor through which intraplatform troughs rapidly respond to positive sea-level fluctuations that can significantly enhance the preservation of the accumulated organic matter. By that, another important goal of this investigation, i.e. the evaluation of Cretaceous Outer Dinaridic intraplatform troughs from the viewpoint of their possible oil potential, is also brought in focus. Thus, the allochthonous Cretaceous and Paleogene carbonates of Outer Dinarides were deposited within tectonically induced and modified synsedimentary intraplatform troughs. Therefore, the debris flows were mostly generated from the line-like rather than point-like sources ; so "base-of-slope-apron" sedimentation model can be envisioned. In the physiographic and environmental sense, the source of carbonate detritus were rudistid reefs, including biostromes, situated at high-energy shoals and various structural highs, all being positioned approximately the platform-trough margin. Furthermore, the so called "oil seepages", well known from some Upper Cretaceous localities in the Adriatic belt, could be in some way connected with mature rocks (matrix) that originated from the deposits that were deposited laterally from the debrites (compare the Upper Cretaceous Tamambra and Tamalipas formations from Mexico).

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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