Autor: Spahić, Darko - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Early Paleozoic Cenerian (Sardic) geodynamic relationships of peripheral eastern north Gondwana affinities: revisiting the Ordovician of the Getic/Kučaj nappe (eastern Serbia)
Autorzy:: Spahić, Darko
Tančić, Pavle
Barjaktarović, Dejan
Powiązania:: https://bibliotekanauki.pl/articles/25173306.pdf
Data publikacji:: 2023
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: eastern north Gondwana
Ordovician ironstones
Cenerian (Sardic) event
glacio-eustatic changes
eastern Serbia
Opis:: Regional tectonic synthesis suggests that a segment of the bipartite eastern Gondwana-type Carpathian-Balkan nappe-stacked Getic/Kučaj/Supragetic basement (eastern Serbia) experienced Cambro-Ordovician Cenerian (Sardic) accretionary-type deformation. The Ordovician basement of the Alpine Getic/Kučaj nappe exposes an earlier-mapped shallow-marine transgressive-type Fe-silicate-rich ironstone sequence. The Ordovician ironstone is used as second-order evidence of a hitherto untraceable tectonically-driven unconformity. Early Paleozoic compression is consistent with the controversial latest Cambrian to intra-Ordovician Cenerian (Sardic) interval, documented by (i) a 488 Ma metamorphic event and available detrital zircon data (Serbo-Macedonian gneissic unit), (ii) a deformed Lower Ordovician Getic/Kučaj brachiopod assembly, and (iii) an intra-Ordovician unconformity dividing the Supragetic basement/”Vlasina complex”. The data further imply that mafic gabbro-dominating sills, cropping out in the northern Getic/Kučaj unit, are consistent with Ordovician back-arc activity. The Getic/Kučaj gabbro is Ordovician in age, piercing a Neoproterozoic–Cambrian (Lower Ordovician) Supragetic/”Vlasina complex”, overlain by a transgressive Silurian–Devonian sedimentary sequence. The emergence of Ordovician mafic intrusions reflects submarine volcanism, while deep-water redox conditions were capable of a sustained supply of Fe (similar to Sardinia). In terms of tectono-palaeogeographic reconstructions, the origin of Ordovician shortening and mafic volcanism is often challenged. The latter is broadly analogous with the embryonic eastern Rheic Ocean, corresponding additionally to the Armorican spur and related intra-continental magmatism.
Źródło:: Geological Quarterly; 2023, 67, 1; art. nr 5
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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Tytuł:: The Neoproterozoic-Paleozoic basement in the Alpidic Supragetic/Kučaj units of eastern Serbia: a continuation of the Rheic Ocean?
Autorzy:: Spahic, Darko
Gaudenyi, Tivadar
Glavaš-Trbič, Bojan
Powiązania:: https://bibliotekanauki.pl/articles/139069.pdf
Data publikacji:: 2019
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: Supragetic ”Kučaj Unit”
Carpatho-Balkanides
Rheic Ocean/seaways
Rheic suture
Kučaj
Reik
Ocean Śródeuropejski
szew transeuropejski
Opis:: This paper attempts to allocate a segment of the Paleozoic Ocean situated in what is now Southeastern Europe (SEE) into a regional geological and paleotectonic synthesis connecting the sedimentary, metamorphic and igneous records associated with the ocean’s cycle. The Supragetic basement (external section of the Carpatho-Balkan arch) represents a tectonically reworked basement vestige of the Neoproterozoic–Lower Paleozoic oceanic floor system recrystallized under regional low temperature greenschist-facies conditions. The regional geological constraints associated with this low-grade basement are integrated with information from the overlying Silurian, Devonian and Lower Carboniferous cap-rocks of the “Kučaj Unit” to demonstrate the presence of a major Paleozoic ocean crossing this segment of SEE. In connection with the Lower Paleozoic north Gondwanan Pan African processes, the low-grade Supragetic basement (including its Devonian cover) is in a complex relationship with the occasionally anchimetamorphic Silurian, Devonian, and Lower Carboniferous deep-water record of the polymetamorphic “Kučaj Unit”. The Upper Devonian–Lower Carboniferous flysch and molasse of the “Kučaj Unit” are interposed with the Neoproterozic–Lower Paleozoic oceanic vestige or with the Supragetic basement with the corresponding Devonian Balkan-Carpathian back-arc ophiolite-bearing lithosphere and its carrier (Danubian Unit). This regional-scale synthesis demonstrates that a segment of the Rheic Ocean referred to as the Saxo-Thuringian seaway and its suture lay to the east, underneath the Permian red-bed overstepping sequence and to the west of the Danubian aggregation. Unlike many of the high-pressure rocks characterizing the segment of the Rheic suture in the Central European Variscides, the SEE zone described here has only a mild overprint.
Źródło:: Acta Geologica Polonica; 2019, 69, 4; 531-548
0001-5709
Pojawia się w:: Acta Geologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Vestiges of Cambro-Ordovician continental accretion in the Carpathian-Balkan orogen: First evidence of the ‘Cenerian’ event in the central Serbo-Macedonian Unit
Autorzy:: Spahić, Darko
Bojić, Zoran
Popović, Danica
Gaudenyi, Tivadar
Powiązania:: https://bibliotekanauki.pl/articles/1835596.pdf
Data publikacji:: 2021
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: Cenerian event
North Gondwana
Serbo-Macedonian Unit
supragetic basement
Lower Paleozoic paleosuture
migmatites
shear zones
Gondwana
dolny paleozoik
migmatyt
strefa ścinania
Opis:: In the Balkans, the Serbo-Macedonian Unit (SMU), Serbia, is thrust bounded by the composite Tethyan Vardar Zone and the Carpatho-Balkanides. The SMU actually emerges from beneath the Neoalpine Miocene-Pliocene deposits. Both provenance and geodynamic position of the SMU are poorly known and still debated. This paper reviews the data hitherto published and includes some new field data interpretations. The SMU is composed of a Neoproterozoic-Cambrian high-grade (para- and ortho-) gneiss with peraluminous magmatic arc components (560-470 Ma). The SMU is in the contact with Neoproterozoic upper Ordovician-Carboniferous low-grade metasedimentary succession of an accretionary wedge assembly represented by the Supragetic basement. The SMU basement became folded, sheared and metamorphosed around 490-450 Ma. Paleomagnetic data point to high southern latitudes and a peri-Gondwanan position of the SMU at that time, which concurs with glaciomarine evidence recorded from the upper Ordovician sediments at the base of an accretionary wedge succession. Based on the published data and field survey in the Stalać region, we correlate the SMU with the pre-Mesozoic gneiss terrane exposed in the Strona-Ceneri zone of the Alps. This terrane, identified as the Cenerian orogen of the Alaskan subduction type, developed at an active margin of Gondwana during middle Ordovician times. The SMU basement, with augen and migmatitic gneisses and arc-related peraluminous magmatic bodies, developed at this margin as part of the Cenerian belt or its equivalent. Such an orogenic edifice proved transient and in the earliest Silurian the SMU fragments drifted away being bound for Baltica (amalgamated Moesian microplate and Danubian terrane) to which they became accreted in the Carboniferous and included in the southern European branch of the Variscan orogen (Marginal Dacides/Carpatho-Balkanides). Despite consider-able Variscan and Alpine reworking, the pre-Variscan, Cenerian-type crustal assembly along with an inferred boundary between the magmatic arc and the accretionary wedge, accompanied by back-arc/forearc deposits, are still decipherable in the Western Balkan countries.
Źródło:: Acta Geologica Polonica; 2021, 71, 2; 219-247
0001-5709
Pojawia się w:: Acta Geologica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Occurrences and characterization of alunite group minerals from the Lece-Radan Oligo-Miocene volcanic complex (Serbia)
Autorzy:: Tančić, Pavle Ivan
Spahić, Darko N
Jovanović, Dragan
Ćirić, Aleksandra
Poznanović-Spahić, Maja
Vasić, Nenad
Powiązania:: https://bibliotekanauki.pl/articles/2058719.pdf
Data publikacji:: 2021
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:: Lece-Radan volcanic complex
alunite group minerals
high-sulphidation epithermal environment
structural factor
Vardar Zone
Serbo-Macedonian metallogenic province
Opis:: The Lece-Radan area of the Oligo-Miocene magmatic complex (former Tethyan active margin, southern Serbia) contains more or less altered volcanic and/or pyroclastic rocks of predominant andesitic, andesitic-dacitic, to dacitic composition. Alteration seen at exposures varies in type and intensity. Samples with documented alunitization were collected from hydrothermally altered zones embedded within local geological units of Oligo-Miocene age. Mineralogical-chemical study has confirmed for the first time the presence of alunite group minerals (thirty-one occurrences) in this area. The minerals of the alunite group described exhibit different compositions that are remarkably consistent with both different alteration types and host lithologies. Six samples characterized in detail show the following solid solutions: Alu52Nal43Hal5, Alu48Nal40Hal12, Nal48Alu35Hal17>/sub>, Nal44Alu35Hal21, Alu36Hal33Nal31 and Hal46Alu27Nal27 (Alu, Nal and Sch refer to alunite, natroalunite and schlossmacherite, respectively). The cross-cutting alunite-bearing fracture pattern and its density indicate a high-sulphidation epithermal palaeoenvironment. The alunite discovery is consistent with the structural setting (fracture frequency) emphasizing its dominant role in controlling the local mineralization.
Źródło:: Geological Quarterly; 2021, 65, 1; 19
1641-7291
Pojawia się w:: Geological Quarterly
Dostawca treści:: Biblioteka Nauki

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