Upper Jurassic Platform succession with characteristics of a deeper water intraplatform trough (Mt. Svilaja, Croatia)

Abstract From the middle part of the Late Jurassic (Kimmeridgian), the hitherto uniform depositional environment of the Adriatic carbonate platform began to show differentiation. In the central part of the platform two intraplatform troughs were formed, one of which stretched from the Karlovac area southward and is known as the Lemeš Trough. The depositional processes that took place within this trough can be observed in the sedimentary succession of Mt. Svilaja. Based on investigated facies characteristics five lithofacies units were distinguished, representing three paleoenvironmental units: (1) shallow subtidal zone below the fair-weather wave-base; (2) intraplatform trough; (3) shallow subtidal zone above the fair-weather wave-base. The environmental changes are related to the tectonically-controlled retrogradation of the shallow subtidal platform, when the deeper-water intraplatform trough area, connected with the open Tethys realm, spread over the sunken part of the platform. Progressive infilling of the trough with bioclastic material led to the re-establishment of the shallow subtidal environment, and the area of the previously existing intraplatform trough was occupied by coral-hydrozoan reefal buildups

Characteristics of a Triassic regional unconformity between the second and third shallow-marine depositional megasequences of the Karst Dinarides (Croatia)

Abstract Two depositional megasequences of the Karst Dinarides that record two different, emersion-separated, depositional periods are presented; the older lasted from the upper part of the Middle Permian to the Middle Triassic, and the younger one from the Late Triassic to the Late Cretaceous. Both megasequences are typified by shallow-water platform deposits; the earlier megasequence formed under epeiric carbonate/clastic platform conditions and the later one under isolated carbonate platform conditions. Significant geodynamic movements within the southern Tethys realm led to Middle Triassic tectonic uplift, i.e. to the emersion of the huge platform area where a regional unconformity between two platform megasequences was formed. Four types of terrestrial phase horizons are identified, each representing different subaerial conditions that existed during the long-lasting emersion. These are: a significant disconformity and related stratigraphic gap between the Upper Scythian and Lower Norian; a tuffaceous horizon between the Upper Anisian and Lower Norian; an Upper Ladinian-Upper Norian brecciated horizon; and an Upper Ladinian-Lower Norian claystone/bauxitic horizon. Due to the widespread diachronous transgression during the Norian, shallow-water platform sedimentation was restored over the entire emergent area, initiating a long-lasting isolated carbonate platform regime

Trijaska kopnena faza zabilježena na slijedu karbonatne platforme krških Dinarida (Hrvatska)

The Triassic carbonate platform succession of the Karst Dinarides was deposited at the southern Tethyan realm. The facies analysis and distant correlation suggests that a regional terrestrial phase occurred in that area during the Triassic. Due to its regional extent, this terrestrial phase has been viewed as a product of tectonically induced uplift of the huge platform area, causing an extensive emersion and distinct disruption in depositional regime when disconformity and/or various types of terrestrial depositional intervals were formed. Two geodynamic scenarios are presented; a) regional, contemporaneous tectonic uplift scenario; and b) diachronous and differential tectonic uplift scenario. During Norian, the uplifted, exposed platform area was flooded and covered by tidal flat-dominated shallow-water carbonates, marking the beginning of wide and long-lasting isolated platform regime.Trijaski karbonatni slijed Krških Dinarida istaložen je na prostranstvu južnog Tetisa. Facijesna analiza i prostorna korelacija tog slijeda naslaga upućuje na regionalnu kopnenu fazu koja je tijekom Trijasa zahvatila ovaj prostor. Svojim regionalnim pružanjem, ova kopnena faza se sagledava kao posljedica tektonski izazvanog izdizanja prostranog platformnog područja, a što je uzrokovalo izrazito okopnjavanje i izrazit prekid dotadašnjeg taložnog režima, čime su nastali taložni diskonformiteti i/ili različiti tipovi kopnenih taložnih slijedova. Predstavljena su dva geodinamska scenarija; a) scenarij regionalnog, istovremenog izdizanja prostranog platformnog područja; i b) scenarij vremenom i intenzitetom različitog izdizanja prostranog platformnog područja. Tijekom Norika, to dotad izdignuto i izloženo platformno područje bilo je preplavljeno i prekriveno plitkovodnim karbonatima plimne zone, označavajući početak prostranog i dugotrajnog taložnog režima izolirane karbonatne platforme

NEW DINOSAUR TRACKSITE IN THE LATE JURASSIC OF KIRMENJAK QUARRY (ISTRIA)

A new dinosaur tracksite was found in the Kirmenjak quarry in Istria. It is located about one kilometre from an already existing tracksite. The footprints are placed on a slightly inclined bedding plane at the base of the succession represented by heavily stylolitised limestones of the Kirmenjak informal lithostratigraphic unit. The age of the limestones is late Tithonian. Fifteen footprints of circular shape with no clear digit or claw impressions were found at the site and are interpreted to have been formed on a tidal flat during a sea-level fall. All of the footprints belong to sauropod dinosaurs. Pes prints are circular to elliptical in shape, whereas manus prints are more elliptical and of smaller size. The average length of the pes prints is 55 cm, which would correspond to a sauropod of approximately 16 meters in length. The trackway is of narrow-gauge type, where the internal trackway width often has a negative value. The length of the strides indicates slow movement of the individual with a speed of less than 2 km/h. Based on stratigraphic position and footprint morphology, the new and the pre-existing tracksites represent the same trackbearing layer

Staklenička Zemlja i Ledena Zemlja

Od početka Zemljinog eona Proterozoika, od prije 2,5 milijardi godina pa sve do danas, klimatski uvjeti na Zemlji variraju između dva osnovna klimatska razdoblja - razdoblja Stakleničke Zemlje (eng. Greenhouse) i razdoblja Ledene Zemlje (eng. Icehouse). Oko 70 % tog vremena Zemlja je provela kao Staklenička Zemlja, a preostalo vrijeme je bila Ledena Zemlja

Distribution of sulphur, phosphorous, iron, and trace elements in bottom sediment cores, mussels and fish from the Punat Bay (Island of Krk, Croatia)

Ships and associated anthropogenic activities release a number of contaminant elements into the marine environment which can be particularly concentrated in restricted circulatory environments including Bays and marinas. One such locality is a Punat Bay, situated at the southern coastline of the island of Krk (west Croatia), which is the largest Croatian marina. The aim of this study was to examine depth profiles of sulfur (S), phosporous (P), iron (Fe), and trace elements (As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sn, Sr, Ti, U, V, Y, and Zn) in six sediment cores (down to 20-30 cm), and from mussels and fish from Punat Bay, by determining their levels with ICP-OES. Data analysis showed that the majority of variables were elevated in a sediment core located closest a port of the marina. Minimum to maximum S, P, and Fe levels in sediments were as follows: 0.4-2.4%, 0.04-320 mg/kg, and 0.2-2.3%, respectively. Correlations among S, P, Fe, and various trace elements were mostly positive (p<0.05). Trace elements were not increased in mussels and fish. This paper shows that the Punat marina has only a limited impact on the environmental status. Several potentially toxic trace elemens (Pb, Cu, etc.) were found to be elevated in a sediment core located closest to the marina

RAZINE SUMPORA, METALA, POLUMETALA, RADIOAKTIVNOSTI I CITOTOKSIČNOSTI U KRŠKIM ISPUSTIMA VODE IZ NAPUŠTENIH RAŠKIH UGLJENOKOPA (SJEVERNI DIO JADRANSKOGA MORA)

Raša coal, mined on the Istrian Peninsula (NW Croatia) for nearly 400 years up to 1999, is notable for having superhigh organic sulfur, and high levels of selenium, uranium, vanadium, and molybdenum. Selenium is the poison responsible for the widespread loss of cattle and sheep. It is essential to human health in trace amounts, but higher concentrations can be harmful. An estimated 4.4Mt. of coal remains underground within marine carbonate rocks. The study area belongs to the coastal karst of the Adriatic Sea. Several abandoned coal-mine discharges (CMDs) were released into local streams and the Raša Bay for decades. Therefore, the water quality of a natural karst spring (Fonte Gaja), the Raša Bay seawater, municipal wastewater, and the Raša CMDs were investigated, focusing on sulfur, selected metal(loid)s (major, minor, and trace), radioactivity, and cytotoxicity. The Fonte Gaja spring water, unrelated to the Raša CMD, served as a reference. Its values of Se, U, V, and Mo (µg/L) were as follows: 1.09, 0.75, 1.37, and 2.04, respectively. However, the respective levels (µg/L) were increased in the rest of the water samples as follows: 10.9, 10.8, 4.60, and 33.1. Water sulfate levels were low though. Total beta activities of the CMDs and Raša Bay water were 235 and 1320 Bq/m3, respectively, below the guideline level of 2000 Bq/m3. The cytotoxicity of water samples on the RTG-2 fish cells was not statistically significant. The large volumes of water involved mean the transport of rather large amounts of Se and U, and their deposition in the Adriatic Sea. Due to the complexity of the karst hydrogeology, knowledge of Se and U circulation patterns is highly needed.Pridobivanje raškoga ugljena u Istri (SZ Hrvatska) trajalo je gotovo 400 godina, sve do 1999. godine. Raški ugljen poznat je po iznimno visokim koncentracijama organskoga sumpora te visokim razinama selena, urana, vanadija i molibdena. Otprije je poznata toksičnost selena na primjerima goveda i ovaca. Za ljudsko zdravlje selen je od presudne važnosti, ali u povišenim je količinama štetan. Procjenjuje se da je još 4,4 milijuna tona raškoga ugljena ostalo pod površinom, unutar marinskih karbonatnih stijena. Područje istraživanja pripada obalnome krškom pojasu Jadranskoga mora. Na nekoliko mjesta nalaze se ispusti podzemne vode iz napuštenih rudnika ugljena (engl. CMD), gdje ta voda desetljećima izbija van na površinu te se izravno ulijeva u lokalne vodotoke i na kraju u Raški zaljev. Stoga su uzeti uzorci vode prirodnoga krškog izvora, morske vode Raškoga zaljeva, komunalne otpadne vode te CMD. U uzorcima su izmjerene koncentracije sumpora, odabranih metala i polumetala (glavnih, sporednih i u tragovima), radioaktivnost te citotoksičnost. Izvorska voda, koja nije u dodiru s CMD-om, poslužila je u referentne svrhe. Njezine odgovarajuće vrijednosti Se, U, V i Mo (μg/L) bile su sljedeće: 1,09, 0,75, 1,37 i 2,04. Međutim, odgovarajuće razine tih četiriju elemenata (μg/L) bile su povišene u ostatku uzoraka vode: 10,9, 10,8, 4,60 i 33,1. Razina sumpora u vodi bila je niska. Ukupne beta aktivnosti CMD-a i vode Raškoga zaljeva iznosile su 235 i 1320 Bq/m3, čime nije bila premašena dopuštena vrijednost od 2000 Bq/m3. Citotoksičnost nekoliko odabranih uzoraka vode nije se pokazala statistički značajnom. Velike količine vode podrazumijevaju transport prilično velikih količina Se i U te njihovo taloženje u Jadranskome podmorju. Zbog složenosti krške hidrogeologije nužno je istražiti obrasce cirkuliranja selena i urana na spomenutome području

Staklenička Zemlja i Ledena Zemlja

Od početka Zemljinog eona Proterozoika, od prije 2,5 milijardi godina pa sve do danas, klimatski uvjeti na Zemlji variraju između dva osnovna klimatska razdoblja - razdoblja Stakleničke Zemlje (eng. Greenhouse) i razdoblja Ledene Zemlje (eng. Icehouse). Oko 70 % tog vremena Zemlja je provela kao Staklenička Zemlja, a preostalo vrijeme je bila Ledena Zemlja

The origin of a complex breccia body within the Upper Cretaceous/Early Eocene succession on Pag Island (Karst Dinarides, Croatia): karstic dissolution and collapse or dilational faulting and collapse origin?

A kilometre west of Pag Town on Pag Island, Croatia, within the Upper Cretaceous shallow-water carbonate succession, there is a large breccia body that has an irregular, quasi-circular shape and a subvertical-oblique position in relation to the bedding of the host rock. The breccia clasts and fragments consist almost entirely of the Upper Cretaceous host rock with only sporadic clasts of the Lower Eocene foraminiferal (alveolinid) limestones. In the brecciated body, there are three breccia types. 1) crackle breccia, 2) mosaic breccia, and 3) chaotic breccia. Based on the textural and structural characteristics of these types of breccia such as chaotic appearance and random fabric, very poorly sorted material, angular fragments, the composition reflecting only the host rock lithology, two genetic scenarios or concepts for the origin of Pag Town breccia body were considered, with observations supporting each of them. The first concept involves host rock dissolution resulting in a widened dissolution cavity into which wall and roof rocks progressively collapsed, and the second concept involves the collapse of voids produced by dilational fault displacement. A common prerequisite to both opposing scenarios is the existence of a subsurface cavity or void where the accumulation of rock clasts and fragments occurred. It is assumed that the timing of the cavity formation is related mainly to karstification during the Late Cretaceous-Early Eocene emersion phase or is related to dilational faulting during the Palaeogene Dinarides thrusting event