Naslov
English
(Carbonate megabeds of Istrian Flysch (Dinaric foreland basin, Croatia))

Autori
Petrinjak, Krešimir ; Bergant, Stanislav ; Korbar, Tvrtko

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

Izvornik
IAS 35th Meeting of Sedimentology, Book of Abstracts / Bábek, Ondrej ; Vodrážková, Stanislava - Prag : Palacký University Olomouc, 2021, 357-357

Skup
IAS 35th International Meeting of Sedimentology

Mjesto i datum
Online ; Prag, Češka Republika, 23.05.2021. - 26.05.2021

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
megaslojevi, fliš, Istra, srednji eocen
(Megabeds, Flysch, Istria, Middle Eocene)

Sažetak
According to the results of extensive geological mapping of the area of central and northern Istria, several sections characterized by coarse carbonate material are selected and investigated in details: Hum, Ripenda, Plomin, Kaldir, Šublentica, Gračišće, Koromačno and Šćurak. The megabeds of Istrian flysch are distinguished from other turbidite beds in succession by their thickness, composition and internal structure. Megabeds are bipartite beds, composed of two divisions: basal breccia or conglomerate (Division I) and normally graded calcirudite/calcarenite (Division II). Two main types of facies of basal division (Division I) are recognized: Facies A - clast supported conglomerate/breccia with sparse carbonate or marl matrix, and Facies B - marl dominated, matrix supported breccia with rip-up clasts and greater total thickness than the Facies A. The lower bedding surface of both types is sharp and erosive. The overlaying Division II is clast supported and normally graded calcirudite, and can be up to 10 m thick. Clasts are composed of various Foraminiferal limestones, large benthic foraminifera, coralline algae and biogenic carbonate detritus. The transition from basal breccia (Division I) to calcirudite can be gradual or sharp. Towards the top of the interval, clast size becomes smaller and there is usually a gradual transition to arenite grain size, and eventually to silt grain size. On the uppermost part of this division, horizontal and cross lamination can be found. The topmost part of the Division II is overlain by massive marl interval. The carbonate material is derived from a carbonate-ramp located in the distal part of the foreland basin (forebulge) and re-deposited in relatively deep-water distal foredeep as wedge- shaped carbonate aprons. The content of marl, in matrix and as rip-up (intra)clasts, implies that the density/debris flow reworked previously deposited flysch sediments, and in places some megabeds directly overlay the carbonate pre- orogenic basement.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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