Pub Date : 2022-06-26DOI: 10.31577/geolcarp.73.3.1
F. Finger, G. Riegler
Igor Broska) Abstract: Many Cadomian and Early Paleozoic basement units in the Alps are considered to be derived from the East Armorican segment of the Gondwana margin. A common assumption is that this East Armorican crustal segment was shifted into the hinterland of West Armorica via a Variscan dextral shear zone. However, the tectonic separation of West and East Armorica could have started earlier during a Late Devonian rifting event. The respective rift zone is supposed to be hidden under the northern nappes of the Alpine–Carpathian chain. This newly proposed sub-Alpine “Cetic rift” was presumably connected with the Upper Devonian Brevenne rift, which is documented in the northern French Massif Central, the southern Vosges and the southern Black Forest. The combined Brevenne–Cetic rift zone may thus represent a major trans-European structure. It is tentatively interpreted as an ephemeral back-arc rift that opened due to southward subduction activities on the northern side of
Igor Broska）摘要：阿尔卑斯山的许多卡多米阶和早古生代基底单元被认为源自冈瓦纳大陆边缘的东阿莫里坎段。一个常见的假设是，这一东Armorica地壳段通过华力西右旋剪切带转移到西Armorica腹地。然而，Armorica西部和东部的构造分离可能在晚泥盆纪裂谷事件中更早开始。各自的裂谷带被认为隐藏在阿尔卑斯山脉-喀尔巴阡山脉的北部褶皱之下。这一新提出的亚高山“Cetic裂谷”可能与上泥盆纪Brevenne裂谷有关，该裂谷记录在法国中部北部、沃斯日南部和黑森林南部。因此，Brevenne-Cetic组合裂谷带可能代表一个主要的跨欧洲构造。它被初步解释为一个短暂的弧后裂谷，由于
{"title":"Is there an Upper Devonian rift zone under the northern front of the Alps separating East and West Armorican crustal segments?","authors":"F. Finger, G. Riegler","doi":"10.31577/geolcarp.73.3.1","DOIUrl":"https://doi.org/10.31577/geolcarp.73.3.1","url":null,"abstract":"Igor Broska) Abstract: Many Cadomian and Early Paleozoic basement units in the Alps are considered to be derived from the East Armorican segment of the Gondwana margin. A common assumption is that this East Armorican crustal segment was shifted into the hinterland of West Armorica via a Variscan dextral shear zone. However, the tectonic separation of West and East Armorica could have started earlier during a Late Devonian rifting event. The respective rift zone is supposed to be hidden under the northern nappes of the Alpine–Carpathian chain. This newly proposed sub-Alpine “Cetic rift” was presumably connected with the Upper Devonian Brevenne rift, which is documented in the northern French Massif Central, the southern Vosges and the southern Black Forest. The combined Brevenne–Cetic rift zone may thus represent a major trans-European structure. It is tentatively interpreted as an ephemeral back-arc rift that opened due to southward subduction activities on the northern side of","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45058381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-16DOI: 10.31577/geolcarp.73.2.3
R. Lukács, S. Harangi, P. Gál, J. Szepesi, A. Di Capua, G. Norini, R. Sulpizio, G. Groppelli, L. Fodor
Repeated explosive eruptions of large volume silicic magmas during the earlyto mid-Miocene resulted in pyroclastic deposits covering at least 50,000 km2 in the Pannonian Basin. They form extended marker horizons and therefore these pyroclastic formations have a great stratigraphic importance. Lithostratigraphic characterization and classification of these rocks go back for more than a century and have been used widely in geological mapping among other things. In this paper, we outline the former stratigraphical schemes developed for silicic pyroclastic products in Northern Hungary; however, using the new geochronological, volcanological, petrological, and geochemical results, we propose a revision of the lithostratigraphic units, including the unit names as well. Four main units are distinguished, named, and described following the International Stratigraphic Guide. Stratotypes of the revised units were also redefined based on accessibility and representativeness. The four newly-defined lithostratigraphic units are the following: (1) The Tihamér Rhyolite Lapilli Tuff Formation (formerly Gyulakeszi Fm.), 18.2–17.1 Ma (Ottnangian–Karpatian); (2) The Bogács Dacite Lapilli Tuff Formation (formerly classified into the Tar Fm.), 16.8–16.2 Ma (Karpatian); (3) The Tar Dacite Lapilli Tuff Formation, 15.1–14.8 Ma (Badenian) and (4) The Harsány Rhyolite Lapilli Tuff Formation, 14.7–14.4 Ma (Badenian) – four formerly existing formations merged in the latter. Three of these units have corresponding distal volcanic products recognized around Hungary and beyond the Pannonian Basin as well. A correlation of the scattered volcanic products can be made based on lithological characteristics, as well as the chemical composition of glass shards, juvenile clasts, and zircon.
{"title":"Formal definition and description of lithostratigraphic units related to the Miocene silicic pyroclastic rocks outcropping in Northern Hungary: A revision","authors":"R. Lukács, S. Harangi, P. Gál, J. Szepesi, A. Di Capua, G. Norini, R. Sulpizio, G. Groppelli, L. Fodor","doi":"10.31577/geolcarp.73.2.3","DOIUrl":"https://doi.org/10.31577/geolcarp.73.2.3","url":null,"abstract":"Repeated explosive eruptions of large volume silicic magmas during the earlyto mid-Miocene resulted in pyroclastic deposits covering at least 50,000 km2 in the Pannonian Basin. They form extended marker horizons and therefore these pyroclastic formations have a great stratigraphic importance. Lithostratigraphic characterization and classification of these rocks go back for more than a century and have been used widely in geological mapping among other things. In this paper, we outline the former stratigraphical schemes developed for silicic pyroclastic products in Northern Hungary; however, using the new geochronological, volcanological, petrological, and geochemical results, we propose a revision of the lithostratigraphic units, including the unit names as well. Four main units are distinguished, named, and described following the International Stratigraphic Guide. Stratotypes of the revised units were also redefined based on accessibility and representativeness. The four newly-defined lithostratigraphic units are the following: (1) The Tihamér Rhyolite Lapilli Tuff Formation (formerly Gyulakeszi Fm.), 18.2–17.1 Ma (Ottnangian–Karpatian); (2) The Bogács Dacite Lapilli Tuff Formation (formerly classified into the Tar Fm.), 16.8–16.2 Ma (Karpatian); (3) The Tar Dacite Lapilli Tuff Formation, 15.1–14.8 Ma (Badenian) and (4) The Harsány Rhyolite Lapilli Tuff Formation, 14.7–14.4 Ma (Badenian) – four formerly existing formations merged in the latter. Three of these units have corresponding distal volcanic products recognized around Hungary and beyond the Pannonian Basin as well. A correlation of the scattered volcanic products can be made based on lithological characteristics, as well as the chemical composition of glass shards, juvenile clasts, and zircon.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46404532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-16DOI: 10.31577/geolcarp.73.2.1
M. Janák, I. Petrik, P. Konečný, S. Kurylo, Milan Kohút, J. Madaras
The Tatra Mountains of the Western Carpathians are a key area for the study of the eastern continuation of the Variscan basement within the Alpine–Carpathian orogenic belt in Central Europe. Metamorphic zonation in the Tatra Mts. displays an inverted metamorphic sequence related to Variscan thrusting and emplacement of gneisses, migmatites and granites over micaschists. Here we present new results of Th–U–Pb dating of monazite in sillimanite-bearing metapelitic gneisses, migmatite and granodiorite from the High Tatra along with petrological interpretation based on thermodynamic modelling. The metapelitic gneisses show the peak metamorphic assemblage garnet + sillimanite + plagioclase + biotite + muscovite + ilmenite + quartz; inclusions of rutile, phengitic muscovite and paragonite in the garnet core indicate an earlier metamorphic stage. Thermodynamic modelling suggests a clockwise, prograde P–T path via staurolite-to-sillimanite sequence reactions from above 6 kbar to ca. 5–6 kbar and 650–700 °C, at mid-crustal levels. Migmatites, with dominant K-feldspar, plagioclase (An12–35) and quartz in the leucosome, underwent partial melting involving biotite dehydration reactions and formation of peritectic, Mn-rich garnet and/or Ti-magnetite at ca. 7–8 kbar and 760–770 °C, during decompression from lower-crustal levels. Monazite composition in metapelitic gneisses differs from that in leucosome of migmatite. The latter shows pronounced Eu-negative anomalies interpreted as the result of co-crystallization with feldspars and higher Y contents indicating higher temperature of crystallization. Monazite ages are identical within 2σ errors and indicate that both metamorphic and melting events occurred in Early Carboniferous, between 350–345 Ma as a consequence of continental collision and crustal thickening in the course of the Variscan orogeny.
{"title":"Variscan metamorphism and partial melting of sillimanite-bearing metapelites in the High Tatra Mts. constrained by Th–U–Pb dating of monazite","authors":"M. Janák, I. Petrik, P. Konečný, S. Kurylo, Milan Kohút, J. Madaras","doi":"10.31577/geolcarp.73.2.1","DOIUrl":"https://doi.org/10.31577/geolcarp.73.2.1","url":null,"abstract":"The Tatra Mountains of the Western Carpathians are a key area for the study of the eastern continuation of the Variscan basement within the Alpine–Carpathian orogenic belt in Central Europe. Metamorphic zonation in the Tatra Mts. displays an inverted metamorphic sequence related to Variscan thrusting and emplacement of gneisses, migmatites and granites over micaschists. Here we present new results of Th–U–Pb dating of monazite in sillimanite-bearing metapelitic gneisses, migmatite and granodiorite from the High Tatra along with petrological interpretation based on thermodynamic modelling. The metapelitic gneisses show the peak metamorphic assemblage garnet + sillimanite + plagioclase + biotite + muscovite + ilmenite + quartz; inclusions of rutile, phengitic muscovite and paragonite in the garnet core indicate an earlier metamorphic stage. Thermodynamic modelling suggests a clockwise, prograde P–T path via staurolite-to-sillimanite sequence reactions from above 6 kbar to ca. 5–6 kbar and 650–700 °C, at mid-crustal levels. Migmatites, with dominant K-feldspar, plagioclase (An12–35) and quartz in the leucosome, underwent partial melting involving biotite dehydration reactions and formation of peritectic, Mn-rich garnet and/or Ti-magnetite at ca. 7–8 kbar and 760–770 °C, during decompression from lower-crustal levels. Monazite composition in metapelitic gneisses differs from that in leucosome of migmatite. The latter shows pronounced Eu-negative anomalies interpreted as the result of co-crystallization with feldspars and higher Y contents indicating higher temperature of crystallization. Monazite ages are identical within 2σ errors and indicate that both metamorphic and melting events occurred in Early Carboniferous, between 350–345 Ma as a consequence of continental collision and crustal thickening in the course of the Variscan orogeny.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44682045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-16DOI: 10.31577/geolcarp.73.2.2
M. Ondrejka, R. Vojtko, M. Putiš, D. Chew, M. Olšavský, P. Uher, O. Němec, Foteini Drakou, Alexandra Molnárová, J. Spišiak
Two representative peraluminous A-type rhyolite samples from the Poniky area (the Drienok Nappe) in the Inner Western Carpathians (central Slovakia) were dated using the LA–ICP–MS U–Pb zircon method. These geochronological data represent the first in-situ isotopic dating study undertaken on these volcanic rocks. Oscillatory zoned zircon crystals yielded concordant Permian (Guadalupian) ages of 271.0 ± 1.5 Ma and 267.5 ± 1.6 Ma for the Poniky rhyolites, which supports their genetic link to the analogous mid-Permian (Guadalupian) rhyolites of adjacent Muráň and Vernár nappes. The Ti-in-zircon geothermometry (corrected using the activities of SiO2 and TiO2 using the rhyoliteMELTS thermodynamic software) indicate mean zircon crystallization temperatures of ~910 to 935 °C for the Poniky rhyolites. The results indicate pulses of anorogenic A-type rhyolitic magmatism were coeval with intrusions of granitic rocks associated with an intraplate extensional tectonic regime triggered by asthenospheric upwelling in the Western Carpathian region. The A-type magmatism was most likely related to the break-up of the Pangea supercontinent during the mid-Permian (~270–260 Ma).
{"title":"Permian A-type rhyolites of the Drienok Nappe, Inner Western Carpathians, Slovakia: Tectonic setting from in-situ zircon U–Pb LA–ICP–MS dating","authors":"M. Ondrejka, R. Vojtko, M. Putiš, D. Chew, M. Olšavský, P. Uher, O. Němec, Foteini Drakou, Alexandra Molnárová, J. Spišiak","doi":"10.31577/geolcarp.73.2.2","DOIUrl":"https://doi.org/10.31577/geolcarp.73.2.2","url":null,"abstract":"Two representative peraluminous A-type rhyolite samples from the Poniky area (the Drienok Nappe) in the Inner Western Carpathians (central Slovakia) were dated using the LA–ICP–MS U–Pb zircon method. These geochronological data represent the first in-situ isotopic dating study undertaken on these volcanic rocks. Oscillatory zoned zircon crystals yielded concordant Permian (Guadalupian) ages of 271.0 ± 1.5 Ma and 267.5 ± 1.6 Ma for the Poniky rhyolites, which supports their genetic link to the analogous mid-Permian (Guadalupian) rhyolites of adjacent Muráň and Vernár nappes. The Ti-in-zircon geothermometry (corrected using the activities of SiO2 and TiO2 using the rhyoliteMELTS thermodynamic software) indicate mean zircon crystallization temperatures of ~910 to 935 °C for the Poniky rhyolites. The results indicate pulses of anorogenic A-type rhyolitic magmatism were coeval with intrusions of granitic rocks associated with an intraplate extensional tectonic regime triggered by asthenospheric upwelling in the Western Carpathian region. The A-type magmatism was most likely related to the break-up of the Pangea supercontinent during the mid-Permian (~270–260 Ma).","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48431348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-16DOI: 10.31577/geolcarp.73.2.4
W. Schwarzhans
A historic collection of fossil otoliths from V. J. Procházka from the lower Badenian of Moravia, Czech Republic, was recently recovered at the Moravian Museum in Brno. Likely with the intent to publish, Procházka labeled the specimens with original identifications; unfortunately, however, publication never occurred. Procházka’s type-material of his earlier publications, notably that from 1893, remains unrecovered and must be considered lost. Several of the species he described in 1893 are problematic because of his less-than-optimal descriptions and documentation. However, with this newly recovered material containing his original identifications, it is now possible to select a neotype for one of those problematic species, Otolithus (Berycidarum) kokeni = Diaphus kokeni, as well as resolve another: Otolithus (Bery cidarum) splendidus. Most of the recovered otoliths originated from the deep-water environment of Borač. Although the locality has been well-studied for otoliths, the recovered collection of Procházka has yielded seven species not previously recorded from the Badenian of the Central Paratethys. One species is described as new: Nezumia prikryli n. sp.
{"title":"A review of Procházka’s otoliths from Lower Badenian deposits from Moravia, Czech Republic (Langhian, Middle Miocene), primarily from Borač","authors":"W. Schwarzhans","doi":"10.31577/geolcarp.73.2.4","DOIUrl":"https://doi.org/10.31577/geolcarp.73.2.4","url":null,"abstract":"A historic collection of fossil otoliths from V. J. Procházka from the lower Badenian of Moravia, Czech Republic, was recently recovered at the Moravian Museum in Brno. Likely with the intent to publish, Procházka labeled the specimens with original identifications; unfortunately, however, publication never occurred. Procházka’s type-material of his earlier publications, notably that from 1893, remains unrecovered and must be considered lost. Several of the species he described in 1893 are problematic because of his less-than-optimal descriptions and documentation. However, with this newly recovered material containing his original identifications, it is now possible to select a neotype for one of those problematic species, Otolithus (Berycidarum) kokeni = Diaphus kokeni, as well as resolve another: Otolithus (Bery cidarum) splendidus. Most of the recovered otoliths originated from the deep-water environment of Borač. Although the locality has been well-studied for otoliths, the recovered collection of Procházka has yielded seven species not previously recorded from the Badenian of the Central Paratethys. One species is described as new: Nezumia prikryli n. sp.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47491494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-16DOI: 10.31577/geolcarp.73.2.5
František Marko, J. Woodhead, D. Scholz, V. Hurai, A. Lačný
Here, we report on the first radiometric dating of pre-Quaternary sinters covering the ENE–WSW striking vertical faults filled with Upper Badenian sands (neptunian dykes) in Mesozoic carbonates of the Devín quarry in the Malé Karpaty Mountains. The 238U/206Pb age of 13.98±0.56 Ma fits well with the former age prediction based on biostratigraphic evidence. Our results provide fault opening age, refine the age of sediments and fossils preserved in the neptunian dykes, and constrain the onset of Badenian sea transgression.
{"title":"238U/206Pb age of the fossil sinter crust (flowstone) covering fault walls of a Badenian neptunian dyke (Devín quarry, Western Carpathians)","authors":"František Marko, J. Woodhead, D. Scholz, V. Hurai, A. Lačný","doi":"10.31577/geolcarp.73.2.5","DOIUrl":"https://doi.org/10.31577/geolcarp.73.2.5","url":null,"abstract":"Here, we report on the first radiometric dating of pre-Quaternary sinters covering the ENE–WSW striking vertical faults filled with Upper Badenian sands (neptunian dykes) in Mesozoic carbonates of the Devín quarry in the Malé Karpaty Mountains. The 238U/206Pb age of 13.98±0.56 Ma fits well with the former age prediction based on biostratigraphic evidence. Our results provide fault opening age, refine the age of sediments and fossils preserved in the neptunian dykes, and constrain the onset of Badenian sea transgression.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48804578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.31577/geolcarp.73.1.5
J. Hrabovský, Andrzej Pisera, E. Gischler
The semi-endophytic coralline alga Lithophyllum cuneatum, which grows partially embedded in its host on its surface and lacks haustoria penetration to this host, was formerly known only from reef environments of the Pacific and Indian Ocean. Here, we report it for the first time from coral reefs of the Caribbean Sea (Belize). The morphoanatomical characteristics of the Caribbean specimens from Holocene sediment cores, which were collected in offshore reef environments, match those of the type material and other specimens reported from the Pacific and Indian Oceans, including the preservation of diagnostic characteristics (cuneate thallus morphology, morphology of the conceptacles and their pore canals, and dimensions of the cells). Similar to L. cuneatum from the Holocene of the Indian and Pacific oceans, Holocene specimens from Belize share two unique hosts represented by the coralline algae Porolithon onkodes and Neogoniolithon sp. The unique occurrence of this species in the Caribbean Sea can be explained either (1) by pre-Pliocene dispersal toward the west from the present-day Indian Ocean area along the Tethyan seaway and/or (2) by dispersal toward the east via the Pacific (Fiji) Ocean when the Panama Isthmus was still open. Although morphologically-equivalent coralline algae can belong to either cryptic or pseudocryptic species, both scenarios imply a broader, more continuous geographic distribution of lineage leading to semi-endophytic Lithophyllum cuneatum prior to the Pliocene, which is in contrast to the more fragmented distribution during the Holocene. Although the lack of information about the geographic range of L. cuneatum prior to the Holocene can be coupled with sampling biases and cannot discriminate among these scenarios, other cases of such disjunct distributions, which were formerly documented among marine invertebrates, indicate that the geographic distribution of this species was less fragmented in the past, and thus supports the Tethyan dispersal hypothesis, including the relict character of its present-day geographic distribution.
{"title":"A first account of the semi-endophytic coralline algae Lithophyllum cuneatum from the Caribbean Sea and its evolutionary and biogeographic significance","authors":"J. Hrabovský, Andrzej Pisera, E. Gischler","doi":"10.31577/geolcarp.73.1.5","DOIUrl":"https://doi.org/10.31577/geolcarp.73.1.5","url":null,"abstract":"The semi-endophytic coralline alga Lithophyllum cuneatum, which grows partially embedded in its host on its surface and lacks haustoria penetration to this host, was formerly known only from reef environments of the Pacific and Indian Ocean. Here, we report it for the first time from coral reefs of the Caribbean Sea (Belize). The morphoanatomical characteristics of the Caribbean specimens from Holocene sediment cores, which were collected in offshore reef environments, match those of the type material and other specimens reported from the Pacific and Indian Oceans, including the preservation of diagnostic characteristics (cuneate thallus morphology, morphology of the conceptacles and their pore canals, and dimensions of the cells). Similar to L. cuneatum from the Holocene of the Indian and Pacific oceans, Holocene specimens from Belize share two unique hosts represented by the coralline algae Porolithon onkodes and Neogoniolithon sp. The unique occurrence of this species in the Caribbean Sea can be explained either (1) by pre-Pliocene dispersal toward the west from the present-day Indian Ocean area along the Tethyan seaway and/or (2) by dispersal toward the east via the Pacific (Fiji) Ocean when the Panama Isthmus was still open. Although morphologically-equivalent coralline algae can belong to either cryptic or pseudocryptic species, both scenarios imply a broader, more continuous geographic distribution of lineage leading to semi-endophytic Lithophyllum cuneatum prior to the Pliocene, which is in contrast to the more fragmented distribution during the Holocene. Although the lack of information about the geographic range of L. cuneatum prior to the Holocene can be coupled with sampling biases and cannot discriminate among these scenarios, other cases of such disjunct distributions, which were formerly documented among marine invertebrates, indicate that the geographic distribution of this species was less fragmented in the past, and thus supports the Tethyan dispersal hypothesis, including the relict character of its present-day geographic distribution.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41748052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.31577/geolcarp.73.1.1
Eleonora Balkanska, S. Georgiev, A. Kounov, Milorad D. Antić, T. Tagami, S. Sueoka, J. Wijbrans, I. Peytcheva
The central parts of the Sredna Gora Zone in Bulgaria have experienced a complex Alpine tectonic evolution. The main tectonic and thermal events since the end of the Triassic are the Late Jurassic–Early Cretaceous (Early Alpine) and Late Cretaceous–Paleogene (Late Alpine) compression separated by Late Cretaceous volcanic-arc magmatism and intra/back-arc extension and basin formation. During most of the Cenozoic, the area was mainly under post-orogenic extension. Here, we present the first apatite and zircon fission-track results and new muscovite and biotite 40Ar/39Ar analysis on upper Carboniferous–Permian granitoids together with Upper Cretaceous volcanic and subvolcanic rocks and Upper Maastrichtian–Danian conglomerates from the Panagyurishte basin, which allowed us to reveal the Alpine thermal and tectonic evolution of the central parts of the Sredna Gora Zone. Our new results disclosed the existence of several thermal and cooling episodes related to different tectonic and magmatic events in the studied area. The 40Ar/39Ar dating of samples from the metamorphic basement constrain the thermal peak of an Early Alpine thermal event at about 140–138 Ma at temperatures between ~ 300 and 400 °C. Through the apatite FT dating and thermal modelling, the time of a Late Alpine (post-Danian) event was constrained at 65–55 Ma, during which the tectonically buried sediments of the Panagyurishte basin reached temperatures of <120 °C. The post-early Eocene cooling and exhumation of the central parts of the Sredna Gora Zone metamorphic basement was related to post-orogenic extension and denudation which took place probably in two stages during the middle Eocene to Oligocene.
{"title":"Low-temperature constraints on the Alpine thermal evolution of the central parts of the Sredna Gora Zone, Bulgaria","authors":"Eleonora Balkanska, S. Georgiev, A. Kounov, Milorad D. Antić, T. Tagami, S. Sueoka, J. Wijbrans, I. Peytcheva","doi":"10.31577/geolcarp.73.1.1","DOIUrl":"https://doi.org/10.31577/geolcarp.73.1.1","url":null,"abstract":"The central parts of the Sredna Gora Zone in Bulgaria have experienced a complex Alpine tectonic evolution. The main tectonic and thermal events since the end of the Triassic are the Late Jurassic–Early Cretaceous (Early Alpine) and Late Cretaceous–Paleogene (Late Alpine) compression separated by Late Cretaceous volcanic-arc magmatism and intra/back-arc extension and basin formation. During most of the Cenozoic, the area was mainly under post-orogenic extension. Here, we present the first apatite and zircon fission-track results and new muscovite and biotite 40Ar/39Ar analysis on upper Carboniferous–Permian granitoids together with Upper Cretaceous volcanic and subvolcanic rocks and Upper Maastrichtian–Danian conglomerates from the Panagyurishte basin, which allowed us to reveal the Alpine thermal and tectonic evolution of the central parts of the Sredna Gora Zone. Our new results disclosed the existence of several thermal and cooling episodes related to different tectonic and magmatic events in the studied area. The 40Ar/39Ar dating of samples from the metamorphic basement constrain the thermal peak of an Early Alpine thermal event at about 140–138 Ma at temperatures between ~ 300 and 400 °C. Through the apatite FT dating and thermal modelling, the time of a Late Alpine (post-Danian) event was constrained at 65–55 Ma, during which the tectonically buried sediments of the Panagyurishte basin reached temperatures of <120 °C. The post-early Eocene cooling and exhumation of the central parts of the Sredna Gora Zone metamorphic basement was related to post-orogenic extension and denudation which took place probably in two stages during the middle Eocene to Oligocene.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46761252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.31577/geolcarp.73.1.3
Silvia Gerátová, R. Vojtko, Alesander Lačný, Katarína Kriváňová
The Muráň fault is perhaps the most distinctive, steeply-dipping, brittle structure in the Western Carpathians. An analysis of brittle deformation was used to gain the succession of tectonic evolution of the Muráň fault by paleostress tensors. Movement on this fault depended on spatial orientation of the principal paleostress axes representing the paleostress fields. The kinematic analysis of fault-slip data confirmed the predominant strike-slip nature of the fault during the entire history, which had sometimes been disrupted by quiescence periods or normal faulting. The Muráň fault may be as old as 85 Ma and originated as a ductile shear zone in deeper crust. It is possible to consider the Muráň fault as sinistral transpressional strike-slip fault during the latest Cretaceous to earliest Paleocene. During this time period, with given orientation of the paleostress field, the fault originated as a semi-brittle to brittle shear zone. A significant re-organization of the paleostress field was carried out approximately on the boundary of the Paleocene and Eocene periods. During this deformation, movement on the Muráň fault changed to dextral, and the secondary positive and negative flower structures in Mesozoic rocks were most likely formed in this time as well. These structures originated after the Danian, since sediments of the Gosau Group are incorporated into these structures. In the late Eocene, activity of the Muráň fault gradually began to decrease, and the fault structure is more or less covered by the upper Eocene transgressive deposits of the Central Carpathian Paleogene Basin. The Neogene evolution is characterised by a continuous change of the orientation of the principal maximum axis σ1 (SHmax, respectively) from the NW–SE through N–S to NE–SW position. The Muráň fault started to become sinistral transpressional to transtensional up to a normal fault, however, the movement along the fault was only several tens of metres. The Quaternary period is characterised by an extensional tectonic regime with the orientation of principal least axis σ3 in the WNW–ESE direction. Late Pleistocene to Holocene normal faulting is indicated by borehole analysis in the alluvial planes of the Rimava and Muráň rivers.
{"title":"The structural pattern and tectonic evolution of the Muráň fault revealed by geological data, fault-slip analysis, and paleostress reconstruction (Western Carpathians)","authors":"Silvia Gerátová, R. Vojtko, Alesander Lačný, Katarína Kriváňová","doi":"10.31577/geolcarp.73.1.3","DOIUrl":"https://doi.org/10.31577/geolcarp.73.1.3","url":null,"abstract":"The Muráň fault is perhaps the most distinctive, steeply-dipping, brittle structure in the Western Carpathians. An analysis of brittle deformation was used to gain the succession of tectonic evolution of the Muráň fault by paleostress tensors. Movement on this fault depended on spatial orientation of the principal paleostress axes representing the paleostress fields. The kinematic analysis of fault-slip data confirmed the predominant strike-slip nature of the fault during the entire history, which had sometimes been disrupted by quiescence periods or normal faulting. The Muráň fault may be as old as 85 Ma and originated as a ductile shear zone in deeper crust. It is possible to consider the Muráň fault as sinistral transpressional strike-slip fault during the latest Cretaceous to earliest Paleocene. During this time period, with given orientation of the paleostress field, the fault originated as a semi-brittle to brittle shear zone. A significant re-organization of the paleostress field was carried out approximately on the boundary of the Paleocene and Eocene periods. During this deformation, movement on the Muráň fault changed to dextral, and the secondary positive and negative flower structures in Mesozoic rocks were most likely formed in this time as well. These structures originated after the Danian, since sediments of the Gosau Group are incorporated into these structures. In the late Eocene, activity of the Muráň fault gradually began to decrease, and the fault structure is more or less covered by the upper Eocene transgressive deposits of the Central Carpathian Paleogene Basin. The Neogene evolution is characterised by a continuous change of the orientation of the principal maximum axis σ1 (SHmax, respectively) from the NW–SE through N–S to NE–SW position. The Muráň fault started to become sinistral transpressional to transtensional up to a normal fault, however, the movement along the fault was only several tens of metres. The Quaternary period is characterised by an extensional tectonic regime with the orientation of principal least axis σ3 in the WNW–ESE direction. Late Pleistocene to Holocene normal faulting is indicated by borehole analysis in the alluvial planes of the Rimava and Muráň rivers.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48646458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-02-01DOI: 10.31577/geolcarp.73.1.2
F. Ramezani, Mahboubeh Hosseini-Barzi, J. Honarmand, A. Sadeghi, J. Armstrong-Altrin
The petrography and geochemistry of clastic rocks from the Gadvan Formation in the Abadan Plain (southwest Iran) were analysed to infer their weathering intensity, compositional maturity, provenance, and tectonic setting. The Index of Compositional Variability (0.47–0.71) indicates high compositional and mineralogical maturity. The Chemical Index of Alteration and the Plagioclase Index of Alteration suggest high intensity of chemical weathering in the source area. In addition, a remarkable high content of REE and LREE/HREE and Th/U ratios, as well as high C-value (1.7) suggest high chemical weathering in the source area. Rounded zircon grains, mineral homogeneity, and a lack of feldspar grains could be related to high weathering and the effect of recycling. Elemental ratios (La/Sc, La/Co, Th/Sc, Th/Co, GdN/YbN, Cr/Ni, Co/Th, La/Yb, and La/Th), bivariate diagrams (La/Sc vs. Co/Th, La/Sc vs. Th/Co, Cr/Th vs. Th/Sc, Th/Yb vs. Ta/Yb, and La/ Yb vs. La/Th), and an enrichment of Nb, Zr, Th, La, Cr, Ni contents imply felsic to intermediate parent rocks, which are similar to the massive granitoids of the Arabian Shield. This could be supported by the dominance of zircon grains, as well as inclusions of rutile and tourmaline in quartz grains in the Gadvan sandstones. Moreover, further petrographical evidences, such as undulatory quartz grains, rare biotite and a small orientation of grains is also related to low-grade metamorphism in a felsic source rock. Finally, the Mudrock Maturity Index and tectonic discrimination diagrams reveal a convergence process in a collisional setting, in which the Zagros Mountains originated.
{"title":"Provenance of the Lower Cretaceous clastic rocks from the Gadvan Formation (Zagros Basin, Iran): Evidences from whole-rock geochemistry and petrography","authors":"F. Ramezani, Mahboubeh Hosseini-Barzi, J. Honarmand, A. Sadeghi, J. Armstrong-Altrin","doi":"10.31577/geolcarp.73.1.2","DOIUrl":"https://doi.org/10.31577/geolcarp.73.1.2","url":null,"abstract":"The petrography and geochemistry of clastic rocks from the Gadvan Formation in the Abadan Plain (southwest Iran) were analysed to infer their weathering intensity, compositional maturity, provenance, and tectonic setting. The Index of Compositional Variability (0.47–0.71) indicates high compositional and mineralogical maturity. The Chemical Index of Alteration and the Plagioclase Index of Alteration suggest high intensity of chemical weathering in the source area. In addition, a remarkable high content of REE and LREE/HREE and Th/U ratios, as well as high C-value (1.7) suggest high chemical weathering in the source area. Rounded zircon grains, mineral homogeneity, and a lack of feldspar grains could be related to high weathering and the effect of recycling. Elemental ratios (La/Sc, La/Co, Th/Sc, Th/Co, GdN/YbN, Cr/Ni, Co/Th, La/Yb, and La/Th), bivariate diagrams (La/Sc vs. Co/Th, La/Sc vs. Th/Co, Cr/Th vs. Th/Sc, Th/Yb vs. Ta/Yb, and La/ Yb vs. La/Th), and an enrichment of Nb, Zr, Th, La, Cr, Ni contents imply felsic to intermediate parent rocks, which are similar to the massive granitoids of the Arabian Shield. This could be supported by the dominance of zircon grains, as well as inclusions of rutile and tourmaline in quartz grains in the Gadvan sandstones. Moreover, further petrographical evidences, such as undulatory quartz grains, rare biotite and a small orientation of grains is also related to low-grade metamorphism in a felsic source rock. Finally, the Mudrock Maturity Index and tectonic discrimination diagrams reveal a convergence process in a collisional setting, in which the Zagros Mountains originated.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48342639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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