Naslov
Siliceous nodular concretions from Upper Cretaceous limestone near Vrgorac (Croatia)

Autori
Posilović, Hrvoje ; Fio, Karmen ; Sremac, Jasenka ; Cvetko Tešović, Blanka ; Brajković, Marija

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

Izvornik
4. Hrvatski geološki kongres s međunarodnim sudjelovanjem, Šibenik, 14-15.10.2010. - Knjiga sažetaka / Horvat, Marija - Zagreb : Hrvatski geološki institut, 2010, 35-36

ISBN
978-953-6907-23-6

Skup
4. Hrvatski geološki kongres s međunarodnim sudjelovanjem

Mjesto i datum
Šibenik, Hrvatska, 14.10.2010. - 15.10.2010

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
silica; nodular concretion; diffusion; Upper Cretaceous; Vrgorac; Croatia

Sažetak
Siliceous-carbonate nodular concretions – perfectly spheroid, in the form of oblate spheres and some of irregular shape – were found within Upper Cretaceous limestone near Vrgorac. Nodule is a mineral body that differs in composition from rock in which it is formed, commonly imestone and dolomite. Sediment surrounding the concretions is wackestone-packstone with abundant pelagic particles (pithonellas and calcispheres), echinoderm fragments and primitive planktic foraminifera. These deposits belong to the hemipelagic Cenomanian–Turonian Sveti Duh Fm (GUŠIĆ & JELASKA, 1990). Concretion outer surface and surrounding host sediment is often impregnated with bituminous material. The source of bituminous material was organic remains possibly giving opal (silica) material for concretion growth. Preservation of bituminous material in carbonates is connected with stagnant pore waters and rapid sea-level rise due to the Oceanic Anoxic Event (OAE) at the Cenomanian– Turonian transition (GU[I] & JELASKA, 1990, and references therein).

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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