Naslov
Modal composition of clastic sediment as an indicator of tectonic and climatic events during the post-rift development of the Pannonian basin; the example from the North Croatian Basin, Republic of Croatia

Autori
Kurečić, Tomislav ; Kovačić, Marijan

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

Izvornik
Environmental, Structural and Stratigraphical Evolution of the Western Carpathians: 12th ESSEWECA Conference, Abstract Book / Hudáčková, N. ; Ruman, A. ; Šujan, M. - Bratislava : Comenius University Bratislava, 2022, 86-87

ISBN
978-80-223-5518-6

Skup
12th Conference: Environmental, Structural and Stratigraphical Evolution of the Western Carpathians (ESSEWECA)

Mjesto i datum
Bratislava, Slovačka, 08.12.2022. - 09.12.2022

Vrsta sudjelovanja
Poster

Vrsta recenzije
Recenziran

Ključne riječi
modal composition ; post-rift ; Pannonian basin

Sažetak
The North Croatian Basin (NCB) is located in the southwestern part of the Pannonian Basin System (PBS). During the postrift phase of its development from the Late Miocene onwards, the basin accumulated a sequence of clastic deposits more than one kilometer thick, initially deposited in a brackish lake, then a freshwater lake, and finally in an alluvial depositional environment (Pavelić & Kovačić, 2018).The aim of this work was to determine the composition and origin of this material and to define its origins by analyzing the modal composition and textural features. The results showed that the Late Miocene sands are texturally mature and have a uniform modal composition throughout the basin. Their composition is dominated by quartz and stable rocks fragments, and heavy minerals are dominated by garnets, epidote and amphibole. The detritus was formed by weathering of metamorphic and older clastic sedimentary rocks located to the north and northwest of the North Croatian Basin, in the area of the Eastern Alps and Western Carpathians. The Pliocene sediments vary greatly in composition in different parts of the NCB. The northwestern part of the basin was at the time still filled with texturally and mineralogically mature sandy detritus transported from the northwest, but the absence of garnet and epidote, with a significant increase in the occurrence of kyanite, staurolite and rutile indicates different source rocks. The Pliocene sands from the southwestern part of the NCB are texturally immature. In addition to material of alpine origin, they also contain carbonate clastic detritus and, in the heavy mineral community, chrom spinel. This detritus originates from nearby sources located to the west and south of the basin in the Inner Dinarides area. The composition and origin of detritus in the eastern part of the NCB is similar to the detritus from the southwestern part of basin. The presence of pyroxene and chrom spinel in clastic material from eastern part of the basin indicates that part of material formed by weathering of basic igneous rocks located to the south in the Inner Dinarides area. During the Pleistocene, loess was deposited on most of the NCB, the sources of which were located in the area of the Danube River floodplain in the northern part of the basin. Besides, mineralogically and texturally immature sandy and gravelly debris of different modal composition was deposited on the margins of the mountains present within the basin and on the southern margin of the basin. The composition of this debris indicates that it is locally derived from the uplifted basement rocks. The observed differences in the modal composition and textural features of the clastic detritus that filled the area of the NCB in the post-rift phase of the basin's development indicate intense tectonic activity and climatic changes throughout the late Miocene, Pliocene, and Pleistocene. During basin floor subsidence and the beginning of basin inversion at the end of the Miocene and in the Pliocene, relatively warm and humid climate contributed to enhanced erosion of the elevated parts of the Alps and the Western Carpathians, supplying a large amount of clastic detritus that deposited in river systems in the study area (Kovačić et al., 2004, Tomljenović & Csontos, 2001, Kurečić et al., 2021). The presence of materials of southern provenance in the composition of the Pliocene clastics suggests the contribution of the Inner Dinarides in the filling of the southern part of the NCB. The deposition of loess is an indicator of colder climatic periods in the Pleistocene. The debris formed by the erosion of pre-Neogene basement rocks of the Pannonian Basin System and accumulated around the present-day mountains in the NCB suggests intensive uplift of individual blocks and the continuation of the compressional phase of basin development in the Quaternary.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA