stjepan coric

<p>The Eocene sediments along the eastern Adriatic coast, deposited in the Dinaric foreland basin, are characterized by an abundance of larger benthic foraminifera (LBF). Representatives of the <em>Nummulites</em> are abundant in limestones deposited in oligotrophic, euphotic to mesophotic carbonate ramp settings and in deep basin sediments (being redeposited in mass - transport deposits). Nummulite-rich Lutetian to Bartonian sediments occur in the northwestern part of the basin and Bartonian to Priabonian in the SE part. For this study, nummulite tests from 60 thin sections of shallow-water limestones collected in the northern and southern parts of the foreland basin were examined in detail. The foraminiferal tests from the different areas show signs of mechanical, biological, or chemical degradation, which varies greatly depending on the area. The study of Lutetian carbonates from Istria and Northern Adriatic region has shown that 2 to 5% of all <em>Nummulites</em> tests show boring marks. The A– and B– generation representatives were equally affected by bioerosion. The traces are small and randomly distributed holes near to the outer walls. The <em>Nummulites</em> tests of Bartonian – Priabonian (Hvar Is., Pelješac) are more frequently bioeroded, about 10% of all specimens show boring marks, and preferably B-generation specimens are destroyed. Destruction varies from multiple holes of the same size distributed in a line along the test diameter to complete destruction of the internal test structure. There is a kind of size selection of the bioeroders, because the boring marks in the B-generation tests are larger, than those in the A-generation tests. The more intense bioturbation suggests greater biological competition in the middle to outer ramp settings around the Middle Eocene Climate Optimum in this part of the Neotethys. There are several possible causes for this: (i) a slightly higher seawater temperature around the MECO led to a higher occurrence of bioeroders (even the appearance of some new forms, such as the recorded crabs from the eastern Neotethys, Schweitzer et al., 2007), or (ii) a difference in sedimentation rate (burial history) between the two areas, or (iii) the Lutetian LBF assemblages were more resistant to biological destruction?</p><p>Schweitzer, C.E., Shirk, A.M., Ćosović, V., Okan, Y., Feldmann, R.M. and Hosgor; I.: New species of Harpactocarcinus from the Tethys Eocene and their paleoecological settings, Journal of Paleontology, 81/5, 1091-1100, 2007.</p><p>This study is conducted within the framework of the scientific project IP-2019-04-5775 BREEMECO, funded by the Croatian Scientific Foundation.</p>

Pollen analyses have been proven to possess the possibility to decipher rapid vegetational and climate shifts in Neogene sedimentary records. Herein, a c. 21-kyr-long transgression-regression cycle from the Lower Austrian locality Stetten is analysed in detail to evaluate climatic benchmarks for the early phase of the Middle Miocene Climate Optimum and to estimate the pace of environmental change. Based on the Coexistence Approach, a very clear signal of seasonality can be reconstructed. A warm and wet summer season with c. 204-236 mm precipitation during the wettest month was opposed by a rather dry winter season with precipitation of c. 9-24 mm during the driest month. The mean annual temperature ranged between 15.7 and 20.8 °C, with about 9.6-13.3 °C during the cold season and 24.7-27.9 °C during the warmest month. In contrast, today's climate of this area, with an annual temperature of 9.8 °C and 660 mm rainfall, is characterized by the winter season (mean temperature: -1.4 °C, mean precipitation: 39 mm) and a summer mean temperature of 19.9 °C (mean precipitation: 84 mm). Different modes of environmental shifts shaped the composition of the vegetation. Within few millennia, marshes and salt marshes with abundant Cyperaceae rapidly graded into Taxodiaceae swamps. This quick but gradual process was interrupted by swift marine ingressions which took place on a decadal to centennial scale. The transgression is accompanied by blooms of dinoflagellates and of the green alga Prasinophyta and an increase in Abies and Picea. Afterwards, the retreat of the sea and the progradation of estuarine and wetland settings were a gradual progress again. Despite a clear sedimentological cyclicity, which is related to the 21-kyr precessional forcing, the climate data show little variation. This missing pattern might be due to the buffering of the precessional-related climate signal by the subtropical vegetation. Another explanation could be the method-inherent broad range of climate-parameter estimates that could cover small sca [...]

Significant synchronous shifts in the chemistry, mineralogy, grain sizes and color of the sediments at 6 m below sea floor (mbsf) at ODP Site 1195 on the Marion Plateau (NE Australia) are interpreted to reflect a major regional paleoceanographic change: the initiation of the southern province of the Great Barrier Reef (GBR). The onset of this massive carbonate production centre nearby resulted primarily in increased deposition of carbonate-rich sediments of neritic origin. Both sedimentation rate and terrigenous input record a coincident decline attributed to inshore trapping of materials behind the reefs. Our best estimate places the development of reef framework in the southern part of the GBR between 560 and 670 kyr B.P., based on an age model combining magnetostratigraphic and biostratigraphic data. The proposed estimation agrees with previous studies reporting an age between 500 and 930 kyr B.P., constraining more tightly their results. However, it does not support research placing the birth of the GBR in Marine Isotope Stage (MIS) 11 (~400 kyr), nor the theory of a worldwide modern barrier reef development at that time.

Belgrade area is a region of high paleobiodiversity, being ranked among the best known in Serbia. The prominent position among a number of Middle Miocene (Badenian) fossiliferous sites in the vicinity of Belgrade (southern Pannonian Basin, Central Paratethys) are occupied with sediments of Rakovica stream, also known as ?Rakovica sands?. Here, the integrated evidence based on new fossil findings of calcareous nannoplankton, foraminifera and molluscs assemblages, allows the stratigraphic revision of the clastic facies of the Rakovica succession. Based on the studies of lithological composition, high paleodiversity molluscs fauna and local palaeogeographical setting, it can be concluded with reasonable certainty that deposits of Rakovica stream entitled ?Rakovica sand? represents a sandstone of the shallow marine (littoral) environment during Lower Badenian time. Large benthic foraminifera Ammonia viennensis (d?ORBigny), and Borelis haueri (d?ORBigny) as well as zone marker nn5 Sphaen...

The formations underlying the Neogene infill of the Vienna Basin are still poorly documented. Until now correlation of subsurface lithostratigraphic units with those of the Rhenodanubian nappe system and the Magura nappe system, outcropping at the basin margins, has been based on extrapolations. A recent drilling campaign in the Bernhardsthal oil field of the northern Vienna Basin in Austria reached the pre-Neogene basement and provided cuttings for biostratigraphic and paleoecological analyses. Based on these data, acquired by using detailed micro- and nanno-paleontological analyses, a Lutetian age (middle Eocene) and a bathyal depositional environment for the Flysch of the Harrersdorf Unit was documented. The lithological similarity of the drilling with the Steinberg Flysch Formation of the Greifenstein Nappe and its Lutetian age suggests, that the middle Eocene part of the Harrersdorf Unit represents a continuation of the Greifenstein Nappe of the Rhenodanubian Flysch, rather tha...

Sediments belonging to the Oligocene Vima Formation (located in the north-western part of the Transylvanian Basin, Romania) have been investigated for calcareous nannofossils content. Biostratigraphically, the sedimentary succession is late Rupelian–Chattian in age, belonging to the NP24 —Sphenolithus distentusand NP25 —Sphenolithus ciperoensisbiozones, to CP19a —Cyclicargolithus floridanusand CP19b —Reticulofenestra bisectaSubzones and to the interval from CNO4 —Sphenolithus distentus/Sphenolithus predistentusCRZ to CNO5 —Sphenolithus ciperoensisTZ. The palaeoenvironment of the Fântânele section was reconstructed by means of calcareous nannofossils and statistics. Multivariate statistics were applied to the composition of autochthonous assemblages and the obtained clusters were used to assess the palaeoecological preferences of the nannofossils. We document changes from more stable open-marine regime, with temperate sea-surface temperatures interfering locally with influx of cooler...

This paper presents the first detailed biostratigraphic investigation of deposits cropping out in stream Sumijevac near Koceljeva (western Serbia). The most important fossil communities and their significance are presented. New biostratigraphic results have been achieved by the study of calcareous nannoplankton, foraminifera and mollusks fauna which clearly indicate the presence of the lower Badenian zone (Lagenid Zone), and defines preciously time of the marine transgression in this area. Further, the revised age of the sedimentary deposits presented here provides the necessary background information for future research of the Badenian sediments of Serbia and neighbouring regions.

Massive evaporites were discovered in the Soltvadkert Trough (Great Plain, Hungary) correlating to the Badenian Salinity Crisis (13.8 Ma, Middle Miocene) on the basis of nannoplankton and foraminifera biostratigraphy. This new occurrence from Hungary previously thought to be devoid of evaporites is part of a growing body of evidence of evaporitic basins inside the Carpathian Arc. We suggest the presence of evaporites perhaps in the entire Central Paratethys during the salinity crisis. Different scenarios are suggested for what subsequently happened to these evaporites to explain their presence or absence in the geological record. Where they are present, scenario A suggests that they were preserved in subsiding, deep basins overlain by younger sediments that protected the evaporites from reworking, like in the studied area. Where they are absent, scenario B suggests recycling. Scenario B explains how the supposedly brackish Sarmatian could have been hyper/normal saline locally by pro...

The Tuzla Basin (NE Bosnia), situated on the southern periphery of the Central Paratethys, was a gulf during Miocene. The thickness of Miocene sediments is about 2300 m. PETROVIC (1979/80) and VRABAC et al. (1990) reported about the stratigraphical position of Miocene sediments from the Tuzla Basin based on foraminifera. Foraminifers and calcareous nannoplankton from Miocene sediments were newly investigated from outcrops in the Tuzla area, and from the borehole Tetima (B-77) located 12 km NE from Tuzla. The borehole is placed in the Dokanj syncline in the south-western edge of Majevica horst anticlinorium. This investigative-exploitation borehole (B-77) was drilled during 2005, and recovered salt formation at depth about 407 m.

Mollusc bearing Neogene strata were collectively designated as ”Grund Beds” in the 19th century. The different lithostratigraphic formations of these Grund Beds were studied in the Austrian Molasse Basin north of the Danube (Alpine-Carpathian Foredeep). Biostratigraphic methods and paleomagnetic measurements revealed that the entire Karpatian Laa Formation spans nannoplankton Zone NN4. It is transgressive on the Lower Miocene, Ottnangian marine sequences. The upper part of the Laa Formation correlates with the first occurrence of Globigerinoides bisphericus and is correlated in the type locality with the reverse Chron C5Cr and the normal chron C5Cn.2n. A distinct unconformity separates the Karpatian and Badenian sequences. The first Badenian transgression of the Molasse Basin resulted in a clastic sequence which, for the time being, has no lithostratigraphic designation. The lower part belongs to nannoplankton Zone NN4, with the first occurrence of Praeorbulina glomerosa glomerosa (...

At the south-eastern margin of the Bohemian Massif in Lower Austria Eggenburgian to Ottnangian sediments are widespread. In the wider surroundings of Eggenburg nearshore clastic deposits of the upper Eggenburgian (Kühnring Mb., Burgschleinitz Fm., Gauderndorf Fm.) occur, which are discordantly overlain by shallow marine sublittoral bioclastic limestone of the Zogelsdorf Fm. Due to the ongoing transgression the Zogelsdorf Fm. shows a fining and deepening upward succession, passing upsection and laterally into marine clays and marls of the Zellerndorf Fm. Two completely cored logs from Limberg and Pulkau show this sedimentary succession above the crystalline basement. As in many outcrops, in the well Limberg KB2 on top of the Burgschleinitz Fm. a transgressional conglomerate occurs at the base of typical Zogelsdorf Fm. followed by pelites of the Zellerndorf Fm. The well Pulkau S1 exhibits between clastics of the Burgschleinitz Fm. and sands and limestone of the Zogelsdorf-Fm. a 4.5 m ...

Abstract The northern Tethyan margin is a key region for determining environmental changes associated with the collision of continental and oceanic tectonic plates and Alpine orogeny. Herein we investigated Middle to Late Eocene neritic to bathyal sediments depo- sited during an interval of unstable climatic conditions. In order to quantify paleoenvironmental changes, we developed a detailed age model based on biozonations of planktic foraminifera, calcareous nannoplankton, and larger benthic foraminifera. The section at Adelholzen covers the almost complete Lutetian Stage (calcareous nannoplankton zones NP15a-16, planktic foraminifera zones E8-11, shallow benthic (foraminifera) zones SBZ13-15) and large parts of the Priabonian Stage (NP18-20, E14/15), while the inter- mediate Bartonian Stage (NP17) is completely missing. Foraminiferal, calcareous nannoplankton, and macrofossil assemblages were analyzed for changes in paleo-water depth, mixing and stratification, paleo-primary produ...

The Maikop Formation, deposited in eastern Azerbaijan during Oligocene and Early Miocene times, represents a prolific source unit for the oils found within the southern Gobustan area and the Kura Depression. Based on biomarker characteristics, the oils are believed to have originated from a clastic source rock deposited in an anoxic to suboxic, transitional marine environment with low to moderate input of terrigenous organic matter. However, due to the thermal immaturity of accessible Maikop rocks, oil-source rock correlation based on biomarker fingerprints is hampered. The results from a sedimentary succession sampled in the Shemakha–Gobustan area near the village of Lahich revealed the presence of marginally mature (Rr = 0.6–0.7%) Maikop rocks. Based on lithology, geochemical data and paleontological analyses, the sampled section contains Upper Eocene and Lower Oligocene sediments. Palynological analyses of dinoflagellate cysts indicate an early Rupelian to early Chattian (Oligoce...

During geological mappings a single huge grey granodiorite block was encountered east of Siegersdorf (near Tulln, Lower Austria), on the northwestern slope of the Heuberg within the sub-alpine Molasse. The block is rich in biotite and was deposited together with smaller (dm to m scale) granitic and sandstone boulders in the informal lithostratigraphic unit „Blockschichten vom Heuberg". Similar granitic debris was also found farther west. These macroscopically very similar rocks (Krenmayr, 2003a) were identified by Humer & Finger (2004) as variscic biotite granite and granodiorite. They are similar to those of the Mauthausen/Freistadt - Group or equivalent rocks, which where encountered in drillings farther east in the Tullner Feld area. Due to the expected high electrical resistivity contrast (silt / marl and granite) the multi electrode geoelectric method was used to study the granite body. The geoelectrical measurements of the granite block with a total of four profiles revea...

The Korneuburg Basin in Lower Austria, about 18 km north of Vienna, is a ca 20 km long and at most 7 km wide asymmetric pull-apart basin formed within the Alpine-Carpathian thrustbelt during last Alpine movements in the Karpatian (late Early Miocene). During the ...

Austrian Neogene basins with marine Karpatian-Badenian sedimentation are situated around the Alpine--Carpathian junction: Styrian Basin, Vienna Basin and Alpine-Carpathian Foredeep north of the Danube. A series of transgression and regression ...

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