Mts. Kalnik and Požeška gora volcaniclastic sequences hold valuable information concerning the Miocene syn-rift evolution of the North Croatian Basin, and the evolution of the Carpathian–Pannonian ...Region and the Central Paratethys. We present volcanological, high-precision geochronological, and compositional data of volcanic glass to constrain their tephrochronology, magmatic provenance, and timing of the initial Central Paratethys flooding of the North Croatian Basin. Based on CA-ID-TIMS U–Pb zircon ages (18.060 ± 0.023 Ma for Mt. Kalnik and 15.345 ± 0.020 Ma for Mt. Požeška gora) and coeval
40
Ar/
39
Ar sanidine ages (18.14 ± 0.38 Ma and 18.25 ± 0.38 Ma for Mt. Kalnik and 15.34 ± 0.32 Ma and 15.43 ± 0.32 Ma for Mt. Požeška gora), Mt. Kalnik rhyolitic massive ignimbrites and Mt. Požeška gora rhyolitic primary volcaniclastic turbidites are coeval with Carpathian–Pannonian Region Miocene post-collisional silicic volcanism, which was caused by lithospheric thinning of the Pannonian Basin. Their affiliation to Carpathian–Pannonian Region magmatic activity is supported by their subduction-related geochemical signatures. Although Mts. Kalnik and Požeška gora volcaniclastics are coeval with the Bükkalja Volcanic Field Csv-2 rhyolitic ignimbrites, North Alpine Foreland Basin, Styrian Basin, Vienna Basin, and Dinaride Lake System bentonites and volcaniclastic deposits, reliable tephrochronological interpretations based on comparison of volcanic glass geochemical composition are not possible due to a lack of data and/or methodological discrepancies. Our new high-precision geochronology data prove that the initial Middle Miocene (Badenian) marine flooding of parts of the North Croatian Basin occurred at least ~ 0.35 Ma (during the NN4 Zone) before the generally accepted ~ 15 Ma maximum flooding age at the basin scale, calibrating the timing of the onset of the widespread “mid-Langhian” Central Paratethys flooding.
The Middle Triassic volcano-sedimentary successions deposited on the passive continental margin during a period of intense extensional tectonics related to the opening of the Neotethys Ocean were ...investigated in NW Croatia. A new palaeogeographic term, the Northwestern Croatian Triassic Rift Basin (NCTRB), is introduced for these successions. Pelagic sediments were deposited on top of older shallow-marine carbonates from the early Illyrian to possibly late Ladinian. Pelagic limestones containing Illyrian ammonites and redeposited benthic foraminifers of the same age indicate the existence of a contemporaneous shallow-marine carbonate environment that supplied material to the deeper parts of the basin. Stratigraphically stacked volcanic and volcanogenic rocks are intercalated with pelagic sedimentary rocks. Submarine basaltic rocks, geochemically characterized as trachy-basalts, are related to deep-rooted faults. Trachy-basaltic hyaloclastites, found intercalated within pelagic limestones, were formed by the quenching of magma that came into contact with cold sea water and subsequent resedimentation of the newly formed basaltic fragments. The majority of volcanogenic deposits belong to the Pietra Verde deposits found higher in the sections. The material for these deposits was produced by explosive volcanic eruptions and deposited by gravitational mechanisms, including pyroclastic density currents. Radiolarians from intercalated radiolarian cherts indicate late Illyrian to early Fassanian age for volcanic activity, as well as episodic eruptions and deposition of pyroclastic material. The uppermost part of the NTCRB successions is characterized by secondary volcaniclastic deposits generated by the rapid reworking of unconsolidated pyroclastic detritus and is deposited as medium- to fine-grained turbidites, marking the gradual filling of the basin. Based on regional correlations, late Ladinian is the most likely age for these deposits, indicating a significant stratigraphic gap in the NTCRB successions.
During the Middle Triassic, intensive volcanic activity took place along the eastern margin of Pangea, including the Greater Adria promontory, due to the Neotethyan oceanization. This resulted in the ...formation of various volcanic and volcaniclastic rock types. The region of NW Croatia, acting as a transition zone between the Southern Alps and the Dinarides, showcases the outcrops of these rocks. The present study investigates the facies of volcaniclastic rocks, the distribution of those facies, formation processes, as well as the genesis of the primary magma to gain a better understanding of the complex geodynamics of this region during the Middle Triassic. Six profiles across the Vudelja quarry front were surveyed using drone imaging and samples were collected for detailed petrographic and geochemical analyses. Two groups of volcaniclastic rocks were identified—
mafic
and
intermediate/felsic
. The former is represented by (I) autoclastic effusive facies and (II) resedimented autoclastic facies, while the latter is represented by (III) secondary pyroclastic facies. Mafic volcaniclastics were generated through basaltic effusions in marine environments, fragmentation in contact with seawater, mixing with shallow marine carbonate clasts, and subsequent redeposition in deeper marine areas. The secondary pyroclastic facies (III) consists of a regionally distributed felsic
Pietra Verde
tuff whose deposits may be related to pyroclastic density currents and syn-eruptive resedimentation by turbidite-like currents. Geochemical data indicate that parental magmas responsible for generating the mafic volcaniclastics had a calc-alkaline composition and originated in ensialic and mature arc settings of an active continental margin. The observed chemical composition is likely inherited from older, arc-related lithologies, associated with the subduction of the Paleotethys Ocean. Parental magmas are thought to have formed during continental rifting of the passive Middle Triassic margins of the Greater Adria through (
i
) partial melting of the heterogeneous lithospheric mantle, which had been metasomatized during an earlier Hercynian subduction, and (
ii
) subordinate processes related to the melting of the upper continental crust and subsequent fractionation. Ar/Ar dating on plagioclase separates yielded an age of 244.5 ± 2.8 Ma for mafic volcaniclastics. This aligns well with biostratigraphic ages of felsic tuffs which crop out on a broader regional scale of the Dinarides, the Southern Alps, and the Transdanubian Range. The overlapping ages obtained from radiometric dating of mafic volcaniclastics and biostratigraphic ages of the felsic
Pietra Verde
tuffs strongly suggest that the Greater Adria region experienced concurrent bimodal volcanism during the Middle Triassic.
Clastic sediments deposited at the bottom of the vertical, nearly 1000 m deep Njemica Cave (Biokovo Mountain, Croatia) were analysed. Owing to the vertical morphology of the cave, the occurrences of ...clastic sediments are sparse. Small, up to decimetre-thick, undisturbed sediment accumulations situated near the siphon lake revealed interesting palaeontological and mineralogical data. These data are used as a useful proxy for discussing depositional processes, the provenance of the sediments and paleo-habitats of the subterranean fauna.
The sub-recent assemblages of ostracods were discovered within the sediment, and they were shown to be correlative to the known endemic species in the wider Dinaric Karst area (Pseudocypridopsis sywulai and Phreatocandona cf. motasi). The well-preserved sediment archive indicates the allogenic origin of the sediment and defines it as an allochthonous infiltrate of the Quaternary. The detritus originates from Pleistocene–Holocene deposits in the surrounding area, whose composition was influenced by volcanic activity in the wide Adriatic region. Sedimentation occurred in a calm aquatic environment by settling from suspension. Therefore the sediments are defined as slackwater deposits.
Paleoecologic (paleoclimatologic) and biostratigraphic studies of pelagic and deep-water deposits rely on the identification of planktonic foraminifera. Here we report and compare the results of ...planktonic foraminiferal assemblages from the Middle Eocene indurated limestones and marls collected in the External Dinarides extracted with acetic acid of different concentrations (50%, 60%, 70% and 80%) and different reaction (exposure) times. The deposits originated within the Dinaric foreland basin, have been assigned to the so-called Transitional beds and Flysch, and are characterized by different ratio of carbonate content and degree of lithification. The aim of this paper is to compare the efficiency of the laboratory procedures for obtaining isolated specimens and to evaluate the impact of preparation procedure on the quality of tests (complete test vs. secondary dissolution effects). For each acetic concentration we assessed:(1)the effectiveness of the treatment in terms of the time required for successful extraction of planktonic foraminifera, and(2)the degree of dissolution by analyses of dissolution proxies, including the weight percentage of sieved residues after disaggregation and preservation features of the tests. Our results indicate that accurate taxonomic analysis of carbonate rocks requires the use of 60% acetic acid for a shorter reaction time, and hydrogen peroxide methods for marls.
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Boreholes Badel-1 and Badel-2, located in Sesvete near Zagreb, were drilled through 71.50 and 84.40 m of Quaternary sediments, respectively. Within these sediments, the occurrence of earthy aggregate ...and 1-2 mm nodules of the deep blue coloured mineral vivianite was observed. Interpretation of the depositional environment, provenance of the sediments and vivianite occurrence was based on sedimentological, mineralogical and palynological analyses. Three different facies within the alluvial environments were interpreted: 1) gravels and sands typical of alluvial environments 2) structureless beds of silts and clays deposited in oxbow lakes, marshes and floodplains 3) chaotic sediments deposited in the upper part of the alluvial fan. Macroscopically, an earthy aggregate is essentially an occurrence of flattened vivianite crystals grouped in clusters. The studied sediments are the product of intensive weathering of different types of rocks from Medvednica Mt. with a prevalence of green-schists. Rocks from Medvednica Mt. as the source of ferrous iron (Fe^sup 2+^) and phosphorus (P), and reductive depositional environments can indicate conditions for genesis of vivianite.
Previous study of mafic extrusive sequences suggested an 80 Ma period of tectono-magmatic evolution of the ROD from intra-continental rifting during the Anisian, to the formation of proto-arc crust ...during the Callovian-Oxfordian. Representative gabbro samples of each geochemical group were dated by the Ar-Ar and/or the K-Ar dating method. The Early Jurassic N-MORB-type gabbros, ∼185 Ma old, signifies a peculiar stage of Palaeo-Tethyan slab break-off. The Late Jurassic IAT-type gabbros (geochemical group B), ∼147 Ma old, is the vestige of a nascent intra-oceanic arc, whilst the Early Cretaceous BABB-type gabbros, ∼100 Ma old, provides evidence of magmatism in the back-arc marginal basin. The analyzed gabbroic rocks enable refinement and completion of the geodynamic evolution of the ROD, from the opening of an ensialic back-arc basin during the Ladinian and a continuous spreading event until the Bajocian. There are many lines of evidence that correlate the geodynamic evolution of the ROD with the Albanide-Hellenide Neo-Tethyan oceanic segment.
The petrographic composition and transport direction of medium and coarse-grained clastic material of Dilj gora Mt. which is located in the south Pannonian basin, shows that this area experienced ...several changes in provenance of the detritus through the Neogene. Detritus for the oldest Lower Miocene (Ravan unit) was generally transported from the south and most probably derived from clastic and carbonate sediments and metamorphic rocks of the Internal Dinarides. Detritus of the Lower-Middle Miocene (Tuk unit) probably originated by weathering of acid magmatic and metamorphic rocks, with significant input of materials from local sources, primarily from the Internal Dinarides and from Pozeska gora and Dilj gora Mts. During the entire Middle Miocene (Zdenci, Dubovik and Glogovica units), and through the older part ofthe Late Miocene (Croatica and Pavlovci unit), the deposition of siliciclastic gravel and sandy detritus was less significant. Only the Middle Miocene deposits (Kasonja unit) contain clastic detritus derived from granitoids, metamorphic and sedimentary rocks of the hinterland. The source area of this detritus was most probably in the Slavonian Mts. (Papuk, Psunj, Pozeska gora Mt.) or the mountains of northern Bosnia (Motajica Mt.). At late Upper Miocene times (Andrasevec and Nova Gradiska units), detritus was derived from different metamorphic and older sedimentary rocks. The structural and mineralogical maturity of these sediments, and their transport directions, indicates an Alpine-Carpathian provenance of the material. Most of the detritus of the Pliocene sediments (Cernik unit) also belong to an Alpine-Carpathian provenance, however a small part of it is of local origin and came from uplifted and mainly sedimentary rocks. Various textural characteristics and diverse modal compositions were determined, and the provenance of Neogene clastic material of Dilj gora Mt. can be attributed to differing source rock compositions and locations of source areas. However, they are also the product of different controls on sedimentation, including different rates of subsidence and extension of the Pannonian Basin (PB) interrupted by compressional events, basin water-level fluctuations connected with global sea-level changes and infilling of PB by delta progradation.
V prispevku sem razmejila pojma vseživljenjsko izobraževanje in vseživljenjsko učenje, ki je bolj populističen izraz. Za vsakega posameznika sta vseživljenjsko izobraževanje in vseživljenjsko učenje ...zelo pomembna, saj se ne končata s formalnim šolanjem, pač pa potekata celo življenje. Kakšne možnosti izobraževanja imajo deprivilegirane skupine zaradi socialnih, psiholoških, kulturnih in ekonomskih razlogov? Tuji avtorji- Freire, Gramschi, Jarvis, Delors - poudarjajo moč izobraževanja za napredek družbe, spremembo miselnosti in odnosov med ljudmi. Raziskave kažejo veliko zaostajanje Slovenije na področju pismenosti v primerjavi z razvitimi državami Evrope in Amerike. Ker je stopnja pismenosti otrok v korelaciji s stopnjo pismenosti staršev oz. izobrazbe staršev, smo lahko opravičeno zaskrbljeni, saj so starši, ki dosegajo višje ravni pismenosti, dejavnejši pri prenašanju bralnih navad in bralne kulture na svoje otroke in je taka pismenost lahko tudi podaljšana roka družine, starši pa pomemben dejavnik pri razvoju delovnih in bralnih navad svojih otrok.Študije primerov devetih otrok in staršev prikazujejo oz. potrjujejo dejstvo, da se v večini primerov izobraževanje in branje staršev neha s formalnim izobraževanjem. Bralne navade so vezane le še na informativno branje dnevnega časopisja. Skrb za branje starši v veliki meri prepuščajo iniciativi otrok in pobudam šole ter učiteljev. To prednost šole in zaupanje učiteljem bi bilo potrebno izkoristiti z uvedbo bralnih krožkov, s prosvetljevanjem staršev preko predavanj in roditeljskih sestankov, vsekakor pa učence učiti aktivnih strategij učenja in branja, ki jih bodo lahko uporabljali tudi pozneje kot odrasli pri vseživljenjskem učenju.
This contribution reports new findings on petrogenesis and possible geotectonic setting of rare subvolcanic Triassic(?) dolerite cropping out in External Dinarides with a goal to contribute to the ...debate on the geodynamic evolution of the continental margin of the Adriatic-Dinaridic platform(s) at the onset of the Mesozoic. Petrography of the studied rocks revealed the crystallization order: clinopyroxene \({\rightarrow }\) plagioclase \({\rightarrow }\) alkali-feldspar \({\pm }\) amphibole \({\pm }\) Fe–Ti oxides. The geochemistry of calc-alkaline dolerite suggested magma generation from a spinel–garnet bearing peridotite mantle source (60sp:40grt). Two mechanisms explaining the origin of dolerite are here suggested. The first one involves a low-grade partial melting of the altered lithospheric mantle and the subduction-modified oceanic lithosphere accompanied with subducted/recycled sediments. The second one proposes a melting of the subduction-altered heterogeneous lithospheric (subcontinental) mantle contaminated and/or metasomatized during an earlier Variscan subduction in the Late Paleozoic. Accordingly, two geodynamic interpretations are suggested: (i) Middle Triassic north-vergent active subduction of the Paleotethys beneath the Andean-type active Laurasian continental margin coupled by the formation of a pericontinental volcanic arc and subsequent extension and back-arc rifting, within the Adria Plate, which led to the formation of locally aborted rift systems and subsidence of the platform, and (ii) Middle Triassic extension, unaffected by contemporaneous active subduction, of the High Karst nappe unit of the Greater Adria as a result of an ephemeral syn-rift volcanic stage, which featured the formation of the Dinaridic aborted rift system followed by the platform subsidence and emergence of local sedimentary basins.
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