Jurassic Sequences of Sosice and Rovinj Localities (Karst Dinarides, Croatia) as Examples of Long-Distance Tectonic-Controlled Deposition on the Adriatic-Dinaric Carbonate Platform

Damir Bucković,Vicko Sviličić

doi:10.15344/2456-351x/2016/110

Abstract

During the Late Jurrasic Adriatic carbonate platform was characterized by complex palaeogeographical and depositional relationships. A major part of the platform remained within restricted lagoonal settings, but some areas of the platform were uplifted, emerged and karstified, characterised by local deposition of bauxites. However, the NE margin of the platform was contemporaneously partially drowned. Facies correlation from two choosen localities in Karst Dinarides, Croatia; Sošice and Rovinj, reveals that during the Late Jurassic increased accommodation loss on Sošice locality coincided with increased accommodation gain on Rovinj locality. This suggests tectonic movements that were synchronous but of different style consequently enabling the relative uplift on one side of the platform but subsidence on its opposite side. Therefore, it is assumed that the extensive drowning event induced by progressive block faulting on the NE Adriatic carbonate platform margin (where present-day Sošice locality is situated) caused a relative uplift on its SE area (where present-day Rovinj locality is situated) resulting in long term emersion event there.

Highlights

The Adriatic Carbonate Platform is one of the largest Mesozoic carbonate platforms of the Perimediterranean region
The NE platform margin is covered by Cretaceous/Palaeogene flysch deposits, Palaeozoic– Triassic nappes and Neogene deposits [2,3,4,5], while the SW margin is covered by Neogene and Quaternary deposits under the recent Adriatic Sea [6]
According to [54] model it can be assumed that Adriatic carbonate platform became slightly inclined and the long-term accommodation loss on the NE part of the Adriatic carbonate platform margin resulted in accommodation gain on its S-SW side

Summary

Introduction

The Adriatic Carbonate Platform is one of the largest Mesozoic carbonate platforms of the Perimediterranean region. The thin beds of the fourth unit represent autochthonous pelagic carbonate mud deposition ("pelagic rain") within the basin environment These areas were located well below the storm-weather wave-base and distant from the platform margin, as indicated by the lack of any sedimentary structures and coarse-grained bioclastic intercalations. 3) The Muča unit represents several kilometers long and several tens of metres thick lens-like sediment body inside the Lim Unit that distinctly differs from the Lim Unit by its composition It consists of a successive series of coarsening-upward cycles, each composed of three texturally and compositionally different facies types; peloidalskeletal wackestones can be found as the lower cycle member, ooid grainstones usually represent the middle cycle member while the bioclastic-ooidal grainstones, more rarely rudstones, make the upper cycle member. Some intraclasts developed pisoid envelopes, and internal sediment was produced when pisoid-intraclastic grainstone-rudstones as the upper cycle member originated

Discussion

Conclusion