Naslov
Lower Cretaceous platform carbonates of Mt Svilaja (Dinaric Karst, Croatia)

Autori
Cvetko Tešović, Blanka ; Glumac, Bosiljka ; Korbar, Tvrtko ; Bucković, Damir ; Brlek, Mihovil

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

Izvornik
The 16th Symposium on The Bahamas and Other Carbonate Regions, Abstracts with Program / Glumac, Bosiljka ; Savares, Michael - San Salvador : Gerace Research Centre, 2012, 11-12

Skup
The 16th Symposium on The Bahamas and Other Carbonate Regions

Mjesto i datum
San Salvador, Bahami, 14.06.2012. - 18.06.2012

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Lower Cretaceous; Platform carbonates; Mt Svilaja; Dinaric Karst; Croatia

Sažetak
Lower Cretaceous strata of Mt Svilaja in the Dinaric Karst region of Croatia were deposited on the Adriatic-Dinaridic carbonate platform (ADCP ; also referred to as the Adriatic Carbonate Platform – AdCP) of the central Tethyan (Mediterranean) region. The two analyzed coeval Aptian–Albian successions of Mt Svilaja (Milešina and Jarebinjak) are only 7 km apart but have some significant differences. Both localities have similar microfacies characteristic of the Lower Aptian OAE-1a interval, but differ in their thickness. The two successions are composed of wackestones and oncoid-bioclastic floatstones with Bacinella irregularis RADOIČIĆ and requieniid rudist fragments. However, the beginning of Early Aptian at Jarebinjak is represented by a diverse rudist (caprinid, caprotinid and monopleurid) assemblage embedded within bioclastic floatstones. This fossil assemblage and a greater thickness of the Lower Aptian interval indicate the presence of open marine conditions (recognized as OAE-1a) and more accommodation space, probably related to synsedimentary tectonics, at Jarebinjak as opposed to Milešina. At Milešina, a several meter thick succession of algal wackestones and peloid-miliolid packstone–grainstones to wackestones directly overlie the Lower Aptian strata. A regressive trend and subaerial exposure features, which are common characteristics of this horizon elsewhere in the Dinaridic Karst region, are also represented here as a thin layer of breccia and/or common charophytes, reflecting an increased fresh water influence. In contrast, the same horizon at Jarebinjak has more distinct regressive trends represented by 7 to 8 thin beds of clay and marl associated with subaerial exposure features. Limestone beds within this occasionally emergent horizon are characterized by algal wackestones and rare species of Orbitolina (Mesorbitolina). Above the emergence horizon, the Upper Aptian? to Lower Albian successions at both localities consist of micritic limestones with variable amounts of calcareous mud, peloids and skeletal grains (rare miliolids and ostracods). These deposits irregularly alternate with thin layers of peloid-intraclastic-skeletal packstone–grainstones and peloid wackestone–packstones with fragments of molluscs (usually gastropods) and benthic foraminifera (e.g. Orbitolina (Mesorbitolina) texana). A stable isotope study was conducted on homogenous micritic matrix samples and variations in carbon isotope compositions proved useful for stratigraphic correlation between the examined successions and for improving their age determination.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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