Naslov
Tectonostratigraphic approach to the geohistory of the Dinarides regarding to carbonate platform development

Autori
Tari, Vlasta

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

Izvornik
Pancardi 2000 - Abstracts / Tomljenović, Bruno ; Balen, Dražen ; Saftić, Bruno - Zagreb : Hrvatsko geološko društvo, 2000, 125-127

Skup
Pancardi 2000

Mjesto i datum
Dubrovnik, Hrvatska, 01.10.2000. - 03.10.2000

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
Dinarides; carbonate platform development; tectonostratigraphic approach

Sažetak
Mountain range of the Dinarides, is a product of alpine orogeny, represent the north-eastern part of the Apulian continental plate, which was separated from Africa and Europe for the most of the Mesozoic (Yilmaz et al., 1996) by Tethys (Sava-Vardar “ocean) since Paleozoic, Slovenian trench since Late Triassic, Budva-Pindos Basin since Early Triassic and Adriatic Block including Ionian-Adriatic Basin since Liassic (Fig. 1). Dinarides became a part of the alpine orogenic system by effective closure of Tethyan oceanic realms and associated basins in the period from Late Jurassic to the Quaternary Main tectonostratigraphic units of the Dinarides are: a) Triassic rifting. Subduction-generated extension created an active continental margin of magmatic, pelagic and horst to graben related deposits overlying Variscian structures and post-Variscian molasse (Tomljenović, 2000). Extension and attenuation of continental crust along the eastern margin of Apulia was generated by subduction of Paleotethian oceanic crust and the generation of oceanic crust in the back-arc basin conditions, starting from Early Triassic to the Late Jurassic. Rifting generated magmatism (Pamić, 1982) migrated westward through the Early to Late Triassic (Norian). Deposition was fault controlled and sedimentation patterns demonstrate a strong differentiation between shelf (platform carbonates), slope and back-arc basin with oceanic type of the lithosphere (Lawrence et al., 1995; Lugović et al., 1991). b) Eastern Thrust Belt, foredeep and foreland: Continental convergence was progressive from Late Jurassic and was first expressed on the eastern margin of the Apulian Dinarides by initial thrusting of rift-related and older lithological units and back-arc related ophiolites, creating the Eastern Thrust Belt and its foredeep. The rest of the carbonate platform toward he west presented the foreland of the generally west directed thrusting. Deposition of platform carbonates dominated on the foreland throughout Cretaceous and Eocene. In the Early Cretaceous compressional stresses begun to be transmitted westward through the Dinarides, causing the migration of the foredeep basin and regional uplift of the Eastern Thrust Belt. Assuming the possibility that Adria and Dinarides were separated by Budva-Pindos Basin, the conclusion can be inferred that at the same time the Adria enclosed and started to underthrust the Dinarides from the southwest. This is supported by the trench to uplifts paleogeography (Grandić et al., 1997) along the eastern margin of the Adria during Albian/Aptian, and especially in the Late Cretaceous. c) Subduction of the Tethyan oceanic plate along the northern margin of the Dinarides culminated from Maastrichtian to Eocene. That is evidenced by accretionary wedge deposits located by oil wells in the basement of the South Pannonian Basin, an east-west trending remnants of the magmatic arc and well exposed retroarc flysch-like deposits (Tari and Pamić, 1998). d) Western Thrust Belt, foredeep and foreland. At the end of the Cretaceous the entire carbonate platform was uplifted until the Early Eocene. During Early and Middle Eocene more than 5.000 meters thick Doinaridic carbonate platform, spanned from Late Triassic to Middle Eocene, was finally drowned under the flysch deposits in the broad foredeep basin of the Western Thrust Belt. e) Collision of Adria and Dinarides. Progressive underthrusting of the Adria created the imbricated structures (accretions) of Adria provenience, related to the shallow decollement (Jurassic to Early Cretaceous anhydrite) in front of the Western Thrust Belt at the beginning of the Oligocene. The structural style of the Dinaridic thrust belt depends on the polyphase tectonic compression and the competence of the sedimentary units involved. The best decollement of the entire Dinarides are extensively developed Permian shales locally interbedded with gypsum or fine-grained clastics of Early/Mid Triassic age. Within the carbonate platform section only the intraplatform basinal shale and platy limestone of Late Jurassic age could be considered as the decollement. The competent carbonate rocks are therefore most responsible for the structural style of the thrust belt. The compression started with ramping along the deep decollement from the root zone with a southwestern tectonic transport. In this way, by progressive overstepping of the thrust faults the various structural forms were created along the Eastern and Western Thrust Belt. The "fault bend folds" and "folded thrust" structures are reworked by footwall deformation and tear fault related folds resulting in the large southwest verging asymmetric folds with forelimb dips up to 80 degrees. f) Wrenching and tectonic inversion. The extremely strong Miocene compression resulted in the Adria indentation into the Southern Alps, along with extension processes that created the Pannonian Basin. Northeast-southwest striking system of the dextral strike slip faults (Oligocene/Miocene) was followed by northwest-southeast striking wrenching in Early and Middle Miocene, affecting South Pannonian Basin, Western Thrust Belt and Adriatic foreland. It is reflected as tectonic inversion (Central Bosnia) and as the system of the right-lateral strike and oblique slip faults, creating the large (Sava and Drava) to small and narrow pull-apart basins (Dinaridic thrust belt) or large flower structures.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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