On the Origin of the Oklad Breccia on the Island of Brac (Southern Croatia)

The Oklad carbonate polymictic breccia from Novo Selo on the island of Brac is a product of the partial destruction of Upper Cretaceous deposits during the Maastrichtian. From a comparison of the lithostratigraphic units of the Upper Cretaceous with the textural and structural features of breccia, it is possible to determine the palaeomorphological pattern of its origin. At the end of the Maastrichtian plicative and disjunctive deformation took place on this part of the Adriatic carbonate platform, resulting in a steep palaeorelief, adequate for formation of the breccia

Two stone medieval heads in the Museum of Slavonia

The Collection of Medieval Stone Monuments of the Museum of Slavonia of Osijek involves, apart from architectonic elements, two stone heads. Although the heads were unclassified and lacked data on their origin and discovery site until recently, the handover record of 1971 suggests that the Regional Institute for Monument Protection rendered, along with other medieval findings from various sites, ’the head of a stone sculpture’ found in a medieval church in Voćin during protection works. The church was the prominent and now again restored Late Gothic Church of the Visitation of the Blessed Virgin Mary. Since other field documentation includes no data on its discovery, the head is likely to have been found during clearance of the church and Franciscan monastery premises. Now there is the problem of determining which head was found in the Voćin church. Katarina and Eufrozina, Nikola Iločki’s daughters and Lovro Iloćki’s sisters, had the church and the Franciscan monastery of Voćin (oppidum Athyna, Attina) built in the last decade of the 15th century. After the Ottoman occupation of Voćin in 1543, the abode in the monastery and church was terminated and the buildings were severely devastated. The fragmentarily preserved and severely damaged head of Christ crowned with thorns was initially considered ’the head of the stone sculpture’ of Voćin because the other head with an ivy wreath was later found in the depot. Analysis of the stone which the heads were made of has catered both for general data on possible places where the sculpture was made and for some specific indicators such as the way of deterioration and emergence of damage or the content of the white protective coating. The attempt of iconographic analysis and search for closer analogies for the second, finely shaped head with a youthful face and curly hair covered with an English ivy wreath have not given any concrete results, just some indications. The position of the head with respect to the fully preserved neck implies that this might be a full figure staring at something above(Christ on the cross, another person) or a head serving as a decorative console table. This issue has entailed different opinions in the paper as well as has its dating. Beside the common standpoint that this is highly valuable late mediaeval stone figural plastics, particularly if the lack of any evidence of the kind from the pre-Turkish period in eastern Croatia is taken into consideration, the head with an ivy wreath has aroused different opinions on its date of manufacture. The estimates range from the end of the 14th or the beginning of the 15th century all the way to the late 19th or the early 20th century. In this view, one should bear in mind that the colleagues could get use of only photo-documentation. The author of the paper is more prone to the latter dates, taking account of the historical data. The views on a possible stylistic and temporal connection with the findings of sculptures from the later reign of Sigismund (the second and third decade of the 15th century) in Buda are also opposing. The same can be said for the stone head which might be found in the Voćin church whereat slight prevalence is given to the head with an ivy wreath. Yet, certain conclusions require more specific data. The fragment of the upper part of the head of Christ crowned with thorns can be, due its fragmentariness, only generally dated to the 14th-15th century period. All the dilemmas and a relatively large range in the dating of the head with an ivy wreath once again point to the importance of keeping precise archaeological museum documentation since otherwise, even the most significant findings can be completely discredited in the professional and scientific sense. Instead of a conclusion one needs to stress the rarity and the artistic and monumental value of the two stone heads for the late medieval period in eastern Croatia and hope that further research of the documentation of other medieval sites in eastern Croatia will ’dig up’ new data on ’the head of the stone sculpture’

The Origin and Importance of the Dolomite-Limestone Breccia Between the Lower and Upper Cretaceous Deposits of the Adriatic Carbonate Platform: An Example from Cicarija Mt. (Istria, Croatia)

On the NE slopes of Cicarija Mt. (N Istria) a 120-150 m thick complex composed of dolomite-limestone breccia crops out between the Lower and Upper Cretaceous deposits. This studied breccia sequence is of post-sedimentary, tectogenic-diagenetic origin. It was formed by polyphase tectonic fracture of the Upper Albian to Lower Cenomanian early- and late-diagenetic dolomite succession with relics of recrystallized limestone, which enabled very important subsequent diagenetic alteration. This included partial dissolution, dedolomitization, recrystallization and calcitization of the fine-grained, crushed dolomite matrix, and centripetal dissolution of dolomite fragments and their cementation by calcite and ferroan calcite cements, as well as the partial collapse of fragments from the roofs of dissolution cavities and limited late-diagenetic silicification (the silica surplus originating from layers of diagenetic quartz from underlying Upper Albian deposits). Such a complex pattern of different events resulted in the high variability of breccia characteristics over relatively small distances, especially near more intensively tectonized zones. The contemporaneous stratigraphic level (Lower to Upper Cretaceous transition) in other parts of the Adriatic Carbonate Platform is also characterised by predominantly late-diagenetic dolomites with relics of limestones (including local occurrences of early-diagenetic dolomites) which are, in more tectonized areas, late-diagenetically altered into tectogenic-diagenetic breccias

A brief insight into the Upper Triassic to Miocene sedimentary succession of the External Dinarides, SE of Dubrovnik (southern Croatia)

The Konavle area located in the very southeast of the Republic of Croatia encompasses a large part of the entire External Dinarides sedimentary sequence, almost 5 km in thickness. It consists of two geologically and geomorphologically different parts, the Donja Banda and the Gornja Banda, separated by one of the most significant faults in the Dinarides, the so-called High Karst Nappe, which divides two regional tectonic units: the less disturbed Adriatic or Dalmatian Zone to the SW and the intensely deformed High Karst Unit to the NE. The Donja Banda as a part of the Dalmatian Zone is composed of Upper Cretaceous carbonates and Palaeogene carbonate and clastic deposits. The Gornja Banda as a part of the High Karst Unit represents a thick sequence of Upper Triassic, Jurassic and Lower Cretaceous carbonate deposits monoclinally inclined towards the SE, passing into Bosnia and Herzegovina where the younger Cretaceous and Palaeogene deposits crop out. The first part of the field trip includes three stops in the Gornja Banda area, with a detailed elaboration of the deposition of shallow-water deposits of the older part of the AdCP. It comprises upper Toarcian–lower Aalenian coated-grain dominated carbonates, upper Kimmeridgian shallow subtidal and peritidal facies with subaerial exposure breccias, and uppermost Tithonian peritidal, laminite-capped cycles with dasyclads and faecal pellets. The second part presents some typical examples of the Upper Cretaceous carbonates and Palaeogene carbonate and clastic deposits of the Konavle region, in order to place them in the regional context of the evolution of the AdCP and External Dinarides. It comprises the oldest Upper Cretaceous rocks in the area, the Santonian–Campanian Gornji Humac fm. and a brief overview of the recent seismicity of the Dubrovnik region, Maastrichtian limestones representing the top of the Cretaceous, Palaeocene(–lower Eocene?) carbonates marking the end of the Adriatic Carbonate Platform in Konavle, Eocene Foraminiferal limestones, Palaeogene clastic deposits and a visit to Medieval fortress of Sokol Grad

A brief insight into the Upper Triassic to Miocene sedimentary succession of the External Dinarides, SE of Dubrovnik (southern Croatia)

The Konavle area located in the very southeast of the Republic of Croatia encompasses a large part of the entire External Dinarides sedimentary sequence, almost 5 km in thickness. It consists of two geologically and geomorphologically different parts, the Donja Banda and the Gornja Banda, separated by one of the most significant faults in the Dinarides, the so-called High Karst Nappe, which divides two regional tectonic units: the less disturbed Adriatic or Dalmatian Zone to the SW and the intensely deformed High Karst Unit to the NE. The Donja Banda as a part of the Dalmatian Zone is composed of Upper Cretaceous carbonates and Palaeogene carbonate and clastic deposits. The Gornja Banda as a part of the High Karst Unit represents a thick sequence of Upper Triassic, Jurassic and Lower Cretaceous carbonate deposits monoclinally inclined towards the SE, passing into Bosnia and Herzegovina where the younger Cretaceous and Palaeogene deposits crop out. The first part of the field trip includes three stops in the Gornja Banda area, with a detailed elaboration of the deposition of shallow-water deposits of the older part of the AdCP. It comprises upper Toarcian–lower Aalenian coated-grain dominated carbonates, upper Kimmeridgian shallow subtidal and peritidal facies with subaerial exposure breccias, and uppermost Tithonian peritidal, laminite-capped cycles with dasyclads and faecal pellets. The second part presents some typical examples of the Upper Cretaceous carbonates and Palaeogene carbonate and clastic deposits of the Konavle region, in order to place them in the regional context of the evolution of the AdCP and External Dinarides. It comprises the oldest Upper Cretaceous rocks in the area, the Santonian–Campanian Gornji Humac fm. and a brief overview of the recent seismicity of the Dubrovnik region, Maastrichtian limestones representing the top of the Cretaceous, Palaeocene(–lower Eocene?) carbonates marking the end of the Adriatic Carbonate Platform in Konavle, Eocene Foraminiferal limestones, Palaeogene clastic deposits and a visit to Medieval fortress of Sokol Grad

Carbon-isotope record and palaeoenvironmental changes during the early Toarcian oceanic anoxic event in shallow-marine carbonates of the Adriatic Carbonate Platform in Croatia

Geochemical (δ13C, δ18O and Mn) compositions of Lower Jurassic shallow-water carbonates cropping out in Croatia were analyzed to elucidate the impact of the early Toarcian oceanic anoxic event (T-OAE) on the Adriatic Carbonate Platform (AdCP). The bulk-rock carbon-isotope records through the studied sections (Velebit-A, Velebit-B and Gornje Jelenje) are characterized by two significant excursions: (i) an initial positive trend interrupted by a pronounced negative shift (c. 2.5‰) that is followed by (ii) an increasing trend of positive values (up to 4.5‰). A comparison with δ13C trends obtained from well-calibrated sections from other localities in Europe shows that the overall character of the early Toarcian negative excursion is clearly reproduced in the curves derived from Croatian shallow-water deposits, which helps to date the sequences and reinforces the global character of the carbon-cycle perturbation. Lower Jurassic sedimentary successions in the studied area show a gradual deepening trend corresponding to deposition of the Toarcian spotted limestones. Assuming that the distinctive negative excursion in the carbon-isotope curves is synchronous across the AdCP, the contact between the spotted limestones and the underlying beds rich in lithiotid bivalves appears to be diachronous within the study area. The Mn record through the Croatian Velebit-A section and, in particular, the rise in concentration (up to 100 ppm) coinciding with the beginning of the δ13Ccarb positive shift, reflects a change in the redox conditions in seawater that allowed diagenetic incorporation of reduced manganese into the calcite structure of the carbonate sediment during the onset of the T-OAE. © 2013 Cambridge University Press