Naslov
Cenomanian-Turonian Boundary in the Northwestern Part of the Adriatic Carbonate Platform (Ćićarija Mtn., Istria, Croatia): Characteristics and Implications

Autori
BRČIĆ, Vlatko ; GLUMAC, Bosiljka ; GRIZELJ, Anita ; FUČEK, Ladislav ; POSILOVIĆ, Hrvoje ; HORVAT, Marija ; MIHELJ, Vedran

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

Izvornik
5. Hrvatski geološki kongres s međunarodnim sudjelovanjem/5. Croatian Geological Congress with international participation ; Knjiga sažetaka/Abstracts book / Horvat, Marija ; Wacha, Lara - Zagreb : Hrvatski geološki institut, 2015, 39-40

ISBN
978-953-6907-50-2

Skup
5. Hrvatski geološki kongres s međunarodnim sudjelovanjem/5. Croatian Geological Congress with international participation

Mjesto i datum
Osijek, Hrvatska, 23.09.2015. - 25.09.2015

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
Sv. Duh formacija; mikrofacijes; glaukonit; OAE2; cenoman–turon; Ćićarija; Jadranska karbonatna platforma
(Sv. Duh Formation; microfacies; glauconite; OAE2; Cenomanian–Turonian; Ćićarija Mtn.; Adriatic Carbonate Platform)

Sažetak
Cenomanian-Turonian boundary in the Ćićarija Mountain region (northern Istria, Croatia) is characterized by calcisphere limestone successions with a firmground and glauconite horizon, bioturbated intervals, tempestites and slumped structures, and laminated algal- cyanobacterial and organic rich interbeds. Compilation of the results of litho-, bio-, and microfacies analyses, X-ray diffraction, SEM, EDS and stable isotope analyses revealed extensive evidence for the reconstruction of marine paleoenvironmental conditions. Shallow water carbonate deposits (the Milna Formation) underlie a drowned-platform succession (the Sv. Duh Formation) on three detailed stratigraphic columns (Vodice–Jelovica, Martinjak and Planik). The transition between these two units is sharp and commonly slumped. The approximate thickness of the Sv. Duh Formation (calcisphere wackestone) is 100 m. The limestones of this formation are mainly greyish to light brown in color, weakly stratified, massive, brittle and tectonically fractured. The entire observed succession is enriched in organic matter. Preliminary δ13C and δ18O stable isotope analyses show the influence of the global Oceanic Anoxic Event (OAE2) on the northwestern part of the Adriatic Carbonate Platform (AdCP). Anoxic and hypoxic conditions in the water column lead to major changes in the shallow water carbonate system of the AdCP. Many benthic foraminifera declined during that time, but the opportunistic species (e.g., planktonic foraminifera and calcareous dinoflagellates, which are less sensitive to change in salinity, temperature, nutrients and oxygen saturation), diversified and expanded greatly. Meanwhile, local and regional tectonics combined with sea- level dynamics led to facies differentiation in the study area. Consequently, the investigated upper Cretaceous deeper-marine lithostratigraphic units of the AdCP represent a record of the relationship between global eustatic changes and local synsedimentary tectonics. The results of this research provide new insights into the character of the Cenomanian-Turonian boundary interval in the northwestern part of the AdCP and allow the correlation of these deposits with global events.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA