Naslov
Heavy mineral chemistry as a provenance indicator for Cretaceous synorogenic clastic formations from the Northern Dinarides (Croatia)

Autori
Luzar-Oberiter, Borna ; Mikes, Tamas ; von Eynatten, Hilmar ; Babić, Ljubomir

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

Izvornik
Book of Abstracts / - Patras : International Association of Sedimentologists (IAS), 2007

Skup
25th IAS Meeting of Sedimentology

Mjesto i datum
Patras, Grčka, 04.09.2007. - 07.09.2007

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Dinarides; Cretaceous; heavy mineral chemistry; provenance

Sažetak
In the area of NW Croatia evidence of early Alpine evolution of the Dinarides is obscured due to strong dismemberment of pre-Tertiary terrains resulting from an intense tectonic history, as well as due to the widespread sedimentary cover of the Pannonian Basin. Our study is based on electron microprobe analyses of heavy minerals from a series of synorogenic clastic formations ranging in age from the Lower to Uppermost Cretaceous, whose isolated exposures occur on the mountains of Medvednica, Ivanscica and Zumberak. Detrital Cr-spinel chemistry reveals that the source ophiolites were predominantly composed of harzburgite peridotites (most data group in the 0.5-0.7 Cr# range) and associated cumulate rocks (19-24% grains classify as magmatic, >0.2 wt% TiO2). Less depleted ultramafic and mafic rocks represented minor sources, and were more significant in the Uppermost Cretaceous. The general similarity of the data among the studied formations suggests that the type of ophiolite source did not change significantly or may reflect reworking in the younger formations. Overall, our Cr-spinel data from both the Lower and Upper Cretaceous indicates a derivation from Type II alpine ophiolites based on the classification of Dick & Bullen (1984), with an affinity towards more depleted peridotites which underwent a complex multistage melting history as might be encountered in a subduction zone. Major and trace element chemistry suggests that most of the detrital tourmalines are metamorphic in origin having derived from Ca-poor metapelitic rocks, with minor contributions from Li-poor granitoids present in all the formations (Henry & Guidotti, 1985, Viator, 2003). Based on concentrations of Cr vs. Nb in detrital rutile (Zack et al., 2002), most of the rutiles also came from metapelitic rocks. A smaller, yet considerable proportion of rutile grains derived from metabasic rocks.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA