Cadomian and post-cadomian tectonics west of the Rhodope Massif – The Frolosh greenstone belt and the Ograzhdenian metamorphic supercomplex

The Frolosh Greenstone Belt (FGB) is traced at a distance of more than 200 km in the territories of Bulgaria, Macedonia and Serbia. It consists of various greenschist-facies rocks (actinolite schists, phyllites, calcareous schists, impure marbles, metasandstones, metadiabases, massive green rocks, etc.) of the Frolosh metamorphic complex with bodies of metabasites (including lherzolites), and inliers (retrogressed mica gneisses and migmatites) from the Ograzhdenian supercomplex. The complex is in­truded by bodies of gabbro (occasionally with ultramafic cumulates), diorites to granites (Struma diorite formation). U-Pb studies on zircons yielded Cadomian ages within the time span between c. 574 and 517 Ma. The Frolosh complex covers the ultrametamorphic (migmatized gneisses and amphibolites; tourma­line-biotite schists; quartzo-feldspathic gneisses; lensoid bodies of metaperidotites to norites) of the Ograzhdenian supercomplex. The Ograzhdenian rocks are intersected by diatectic metagranites over­printed by amphibolite-facies metamorphism. Dominant U-Pb ages vary between 470 and 430 Ma. The contact between the Frolosh complex and the Ograzhdenian supercomplex has been subject of long dis­cussion and controversial interpretations. Now we emphasize on the multistage developments of both complexes as demonstrated both by field evidence and isotopic dating. The Ograzhdenian supercomplex has been subject of Precambrian tectonometamorphism witnessed by Rb-Sr whole-rock isochron data and relict U-Pb zircon data. Ordovician to Silurian anatectites (metatectic migmatization, diatexis) are in­truded by Permo-Triassic granites. The contact between the Ograzhdenian supercomplex and the covering Frolosh complex is regarded as a thick complex zone of multistage tectonometamorphic development rather than a “razor-blade” surface of one-stage origin. As a boundary between suprastructure and infra­structure, it played an important role throughout the Phanerozoic, and acted as a screen with a steep ther­mal gradient during the Ordovician-Silurian anatexis and metamorphism in the Ograzhdenian supercom­plex. For to verify this hypothesis, new detailed structural and isotopic studies are needed

Subglottotracheal Adenoid Cystic Carcinoma in a 16-Year-Old Female—A Case Report

Cystic adenoid carcinoma (ACC) is a rare malignant epithelial tumor arising from exocrine glands and accounts for only 1% of head and neck cancers. ACCs are common in the fifth and sixth decades of life, predominantly in women, and characterized by slow progression, local aggression, recurrence, and high metastasis. Subglottotracheal ACC is a rare tumor in the pediatric population, with only a few cases reported in the literature. We present a case of a 16-year-old female who was diagnosed with ACC in the subglottic and tracheal region. The patient presented with respiratory failure but without a history of dysphonia, dyspnea, stridor, or dysphagia. The diagnosis was confirmed by a biopsy, and subsequent imaging studies showed a large tumor involving the subglottic and tracheal region. The therapeutic management of this patient has been challenging due to the rarity of this tumor in the pediatric population and the potential long-term complications associated with tumor recurrence and psychological impact. This case highlights the diagnostic and therapeutic challenges in the management of subglottotracheal ACC in children and the importance of a multidisciplinary approach to optimize patient outcomes

About a peri-Gondwanan-North African enlarged acceptance of the Caledonian Orogeny

The notion of “Caledonian Orogeny” is restricted by most authors to the Ordovician-Devonian thermotectonic events associated with the Laurentia-Baltica- Avalonia suturing. However, some views consider an orogeny as the sum of tectonic, metamorphic and magmatic events accompanying an entire supercontinent assembly or Wilson cycle. Following this line of thinking, the Caledonian and Variscan orogenies successively assembled Pangea. During the Ordovician Period, rifting, collision, deformation, metamorphism and magmatism took place within the Gondwana margin. All these events are known today in the basement of the Cadomian terranes from Iberia through the Alps up to the Romanian Carpathians and Balkans. We plead here for an enlargement of the “Caledonian Orogeny” terminology to these events and places, under the name of the “Caledonian North African orogenic event or Caledonian North African orogen

New data on facies development and micropaleontology of the eastern margin of the Getic Carbonate Platform (South Carpathians, Romania): case study of Mateiaş Limestone

Mateiaş Limestone represents a lithostratigraphic unit included in the Braşov Series, which is a component of the eastern end of the Getic Nappes’ cover (the Getic carbonate platform). The study of the Mateiaş Limestone in Hulei-Mateiaş-Măgura area has evidenced three main facies, and five microfacies types. The Kimmeridgian (possibly also Early Tithonian) age of the Mateiaş Limestone has been assigned based on a microfossil association identified in thin sections. The regional framework, as well as their sedimentological and micropaleontological features point to the deposition of these limestones on shelf margin and slope environments; the succession in the studied area corresponds to the lower-median part of the carbonate deposits developed in more internally eastern parts of the Getic carbonate platform

Peri-Gondwanan terranes in the Romanian Carpathians: A review of their spatial distribution, origin, provenance, and evolution

The basement of the Romanian Carpathians is made of Neoproterozoic to early Paleozoic peri-Gondwanan terranes variably involved in the Variscan orogeny, similarly to other basement terrains of Europe. They were hardly dismembered during the Alpine orogeny and traditionally have their own names in the three Carpathian areas. The Danubian domain of the South Carpathians comprises the Drăgşan and Lainici-Păiuş peri-Amazonian terranes. The Drăgşan terrane originated within the ocean surrounding Rodinia and docked with Rodinia at ∼800 Ma. It does not contain Cadomian magmatism and consequently it is classified as an Avalonian extra-Cadomian terrane. The Lainici-Păiuş terrane is a Ganderian fragment strongly modified by Cadomian subduction-related magmatism. It is attached to the Moesia platform. The Tisoviţa terrane is an ophiolite that marks the boundary between Drăgşan and Lainici-Păiuş terranes. The other basement terranes of the Romanian Carpathians originated close to the Ordovician North-African orogen, as a result of the eastern Rheic Ocean opening and closure. Except for the Sebeş-Lotru terrane that includes a lower metamorphic unit of Cadomian age, all the other terranes (Bretila, Tulgheş, Negrişoara and Rebra in the East Carpathians, Someş, Biharia and Baia de Arieş in the Apuseni mountains, Fagaraş, Leaota, Caraş and Padeş in the South Carpathians) represent late Cambrian–Ordovician rock assemblages. Their provenance, is probably within paleo-northeast Africa, close to the Arabian-Nubian shield. The late Cambrian–Ordovician terranes are defined here as Carpathian-type terranes. According to their lithostratigraphy and origin, some are of continental margin magmatic arc setting, whereas others formed in rift and back-arc environment and closed to passive continental margin settings. In a paleogeographic reconstruction, the continental margin magmatic arc terranes were first that drifted out, followed by the passive continental margin terranes with the back-arc terranes in their front. They accreted to Laurussia during the Variscan orogeny. Some of them (Sebeş-Lotru in South Carpathians and Baia de Arieş in Apuseni mountains) underwent eclogite-grade metamorphism. The Danubian terranes, the Bretila terrane and the Someş terrane were intruded by Variscan granitoids

Tongue Base Ectopic Thyroid Tissue—Is It a Rare Encounter?

Failure in the embryological development of the thyroid in adults is rarely seen. We present the case of a 79-year-old female patient who complained of dysphagia and progressive upper respiratory obstruction, which started 12 months prior to her admission. An ENT clinical exam revealed a tongue base, spherical, well-defined tumour covered by normal mucosa. Further assessments established the diagnosis of the tongue base ectopic thyroid tissue. Due to the patient’s symptoms, a transhyoid tongue base tumour removal was performed. The selected patient gave consent for participation and inclusion in this paper, in compliance with the 1964 Helsinki declaration

A few single crystal zircon ages from the Padeş suite orthogneisses (Southern Carpathians, Romania)

The Padeş suite from the Poiana Ruscă Mountains is a component of the Padeş Paleozoic terrane. The Padeş terrane evolved as an island arc between the Cadomian Sebeş-Lotru and Făgăraş terranes, the main parts of the Getic crystalline in the Southern Carpathians. Evaporated single zircon grains offered 394±20 Ma, 546±20 Ma, 655±19 Ma, 1305±17 Ma, and 1538±17 Ma ages. The 394 Ma age has been interpreted as an early Variscan collision age, 546 Ma as the protolith age and the other ages as signifying Cadomian and Saharan detrital zircons. Similar to the terranes in the Apuseni Mountains, the Padeş terrane has a North African-Gondwanan provenance

New U/Pb and Pb/Pb zircon ages from the Biharia terrane rocks, Apuseni Mountains, Romania

The Biharia sequence from the Apuseni Mountains is a component of the Biharia Paleozoic terrane. The Biharia terrane probably evolved as an island arc between the Cadomian Someş and Baia de Arieş terranes. A gneissic metagranodiorite associated with metabasites from the Valea Ierţii creek, was sampled for U/Pb and Pb/Pb zircon age determination. The zircons extracted out of the sampled rock were subjected both to dilution and evaporation methods. Dilution method offered Concordia intercepts at 227±23 Ma, 312±13 Ma, 465.7+8.4/-8.0 Ma, 703±21 Ma and 1604±45 Ma. Evaporated zircon grains gave 450±20 Ma and 543±17 Ma. The 227±23 Ma age and 312±13 Ma age have been interpreted as Pb loss due to the final effect of the Permian widespread magmatism and late Variscan anatexis respectively. The 465.7+8.4/-8.0 Ma and 450±50 Ma ages probably represent the protolith generation time. The 543±17 Ma is viewed as an inherited Cadomian age and the 703±21 and 1604±45 Ma might represent Cadomian and Saharan detrital zircon ages

New U/Pb and Pb/Pb zircon ages from the Biharia terrane rocks, Apuseni Mountains, Romania

The Biharia sequence from the Apuseni Mountains is a component of the Biharia Paleozoic terrane. The Biharia terrane probably evolved as an island arc between the Cadomian Someş and Baia de Arieş terranes. A gneissic metagranodiorite associated with metabasites from the Valea Ierţii creek, was sampled for U/Pb and Pb/Pb zircon age determination. The zircons extracted out of the sampled rock were subjected both to dilution and evaporation methods. Dilution method offered Concordia intercepts at 227±23 Ma, 312±13 Ma, 465.7+8.4/-8.0 Ma, 703±21 Ma and 1604±45 Ma. Evaporated zircon grains gave 450±20 Ma and 543±17 Ma. The 227±23 Ma age and 312±13 Ma age have been interpreted as Pb loss due to the final effect of the Permian widespread magmatism and late Variscan anatexis respectively. The 465.7+8.4/-8.0 Ma and 450±50 Ma ages probably represent the protolith generation time. The 543±17 Ma is viewed as an inherited Cadomian age and the 703±21 and 1604±45 Ma might represent Cadomian and Saharan detrital zircon ages