Pub Date : 2023-10-31DOI: 10.31577/geolcarp.2023.19
Hamideh Sahraei, Mohsen Ehteshami-Moinabadi, Seyed Ahmad Alavi
: The Zagros Fold-Thrust Belt is one of the most tectonically active regions in the world. The seismicity of this belt is affected by various factors and has certain complexities. This paper provides the results of assessment of temporal and spatial seismicity variations of the central portion of the belt in Fars and Bushehr provinces and their link to regional tectonic properties. Relatively, everywhere in the belt, the geometry of the folds has been mainly affected by thrusts and basement faults. There is a meaningful link between seismic activity and folding in the belt. The most abundant types of folds are detachment folds, fault bend and fault propagation folds. They play an important role in the spatial seismicity of the area. The maximum number of seismic events have medium magnitude which ranges between 2.5 and 3. There is a decreasing trend of a and b parameters from south-west to north and north-east where the occurrence of higher magnitudeearthquakesisexpected.Temporalanalysisofseismicityshowsthatearthquakeswithmagnitude≥ 6.5have a ten-year return period in the region. The occurrence of several earthquake groups in the belt was in the form of swarms showing point or linear spatial distribution. Some of these possible swarms are around transverse faults, salt domes and some are related to blind faults, which indicate the complexity of the seismicity in this belt. Spatial distribution of low magnitude seismic clusters is also influenced by two other factors (1) existence of frequent salt domes many of which might be active and their spatial links to major faults and (2) human-related
{"title":"Variation of seismicity parameters and its link to tectonic features of the central portion of the Zagros Fold-Thrust Belt, Iran","authors":"Hamideh Sahraei, Mohsen Ehteshami-Moinabadi, Seyed Ahmad Alavi","doi":"10.31577/geolcarp.2023.19","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.19","url":null,"abstract":": The Zagros Fold-Thrust Belt is one of the most tectonically active regions in the world. The seismicity of this belt is affected by various factors and has certain complexities. This paper provides the results of assessment of temporal and spatial seismicity variations of the central portion of the belt in Fars and Bushehr provinces and their link to regional tectonic properties. Relatively, everywhere in the belt, the geometry of the folds has been mainly affected by thrusts and basement faults. There is a meaningful link between seismic activity and folding in the belt. The most abundant types of folds are detachment folds, fault bend and fault propagation folds. They play an important role in the spatial seismicity of the area. The maximum number of seismic events have medium magnitude which ranges between 2.5 and 3. There is a decreasing trend of a and b parameters from south-west to north and north-east where the occurrence of higher magnitudeearthquakesisexpected.Temporalanalysisofseismicityshowsthatearthquakeswithmagnitude≥ 6.5have a ten-year return period in the region. The occurrence of several earthquake groups in the belt was in the form of swarms showing point or linear spatial distribution. Some of these possible swarms are around transverse faults, salt domes and some are related to blind faults, which indicate the complexity of the seismicity in this belt. Spatial distribution of low magnitude seismic clusters is also influenced by two other factors (1) existence of frequent salt domes many of which might be active and their spatial links to major faults and (2) human-related","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"109 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135870115","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 : 2023-10-31DOI: 10.31577/geolcarp.2023.17
Vratislav Hurai, Monika Huraiová, Ondrej Nemec, Patrik Konečný, Luca Reato
: Tertiary alkali basalts in the South-Slovakian Basin contain homogeneous clinopyroxene megacrysts, composite phenocrysts with chemically and optically homogeneous olive-green cores overgrown by oscillatory zoned rims, and fragments of clinopyroxene-rich igneous cumulates. Discrimination based on Ca, Na, Ti and Cr concentrations defined clinopyroxenes with alkalic, tholeiitic and transitional affinities. Single-pyroxene thermobarometry revealed that the incipient clinopyroxene crystallization occurred at 1300–1350 °C and 2.0–2.2 GPa, thus identifying the zone of mantle melting in a depth of >70 km. The highest frequency of pressure data from clinopyroxene-rich mafic cumulates, betwen 0.7 and 1.2 GPa, indicate stagnant basaltic reservoirs located beneath the Moho discontinuity, 30–43 km deep. Late fractionation products of alkali basalt derivatives may have occurred as laccoliths and dykes in the lower crust. Thermodynamic modelling of mineral assemblages of cumulate xenoliths revealed that parental melts for both alkalic and tholeiitic affinities were silica-undersaturated (46–46.5 wt. % SiO 2 ) and moderately alkalic (index of alkalinity 2.0–3.8, Mg# ~50) basalt to basanite, with pre-eruptive water contents between 1 and 2 wt. %. Amphibole–biotite– titanite–ilmenite–plagioclase cumulates recorded the advanced stage of fractionation of more calcic basalt at 900–920 °C and 0.65 GPa. Deep-seated basalt reservoirs have been less alkalic than erupted lavas, the latter showing a Mg depletion and an increasing aluminium saturation index diagnostic of the extensive crystal separation on the way to the surface. Olive-green megacrysts and cores of zoned phenocrysts originated at lower temperatures and higher pressures than their autocrystic rims. The megacrystic assemblage of Fe-diopside–Al-augite, Mg-calcite, apatite, ulvöspinel, and disintegrated amphibole crystallized from evolved, relatively cold (~950–1100 °C), Fe-rich carbonatite–alkalic silicate melt within the depth interval of 26–53 km, corresponding to a lithostatic pressure of 0.7–1.5 GPa. The silicate–carbonate–phosphate melt fraction probably originated in the subducting slab of oceanic crust.
{"title":"Systematics of clinopyroxene phenocrysts, megacrysts, and cumulates in Tertiary basalts of southern Slovakia with implications in the structure of lithospheric mantle","authors":"Vratislav Hurai, Monika Huraiová, Ondrej Nemec, Patrik Konečný, Luca Reato","doi":"10.31577/geolcarp.2023.17","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.17","url":null,"abstract":": Tertiary alkali basalts in the South-Slovakian Basin contain homogeneous clinopyroxene megacrysts, composite phenocrysts with chemically and optically homogeneous olive-green cores overgrown by oscillatory zoned rims, and fragments of clinopyroxene-rich igneous cumulates. Discrimination based on Ca, Na, Ti and Cr concentrations defined clinopyroxenes with alkalic, tholeiitic and transitional affinities. Single-pyroxene thermobarometry revealed that the incipient clinopyroxene crystallization occurred at 1300–1350 °C and 2.0–2.2 GPa, thus identifying the zone of mantle melting in a depth of >70 km. The highest frequency of pressure data from clinopyroxene-rich mafic cumulates, betwen 0.7 and 1.2 GPa, indicate stagnant basaltic reservoirs located beneath the Moho discontinuity, 30–43 km deep. Late fractionation products of alkali basalt derivatives may have occurred as laccoliths and dykes in the lower crust. Thermodynamic modelling of mineral assemblages of cumulate xenoliths revealed that parental melts for both alkalic and tholeiitic affinities were silica-undersaturated (46–46.5 wt. % SiO 2 ) and moderately alkalic (index of alkalinity 2.0–3.8, Mg# ~50) basalt to basanite, with pre-eruptive water contents between 1 and 2 wt. %. Amphibole–biotite– titanite–ilmenite–plagioclase cumulates recorded the advanced stage of fractionation of more calcic basalt at 900–920 °C and 0.65 GPa. Deep-seated basalt reservoirs have been less alkalic than erupted lavas, the latter showing a Mg depletion and an increasing aluminium saturation index diagnostic of the extensive crystal separation on the way to the surface. Olive-green megacrysts and cores of zoned phenocrysts originated at lower temperatures and higher pressures than their autocrystic rims. The megacrystic assemblage of Fe-diopside–Al-augite, Mg-calcite, apatite, ulvöspinel, and disintegrated amphibole crystallized from evolved, relatively cold (~950–1100 °C), Fe-rich carbonatite–alkalic silicate melt within the depth interval of 26–53 km, corresponding to a lithostatic pressure of 0.7–1.5 GPa. The silicate–carbonate–phosphate melt fraction probably originated in the subducting slab of oceanic crust.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"44 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135869489","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 : 2023-10-31DOI: 10.31577/geolcarp.2023.18
Weronika Baliniak
: The Middle Eocene microfauna of the Fore-Magura Unit contains rich foraminiferal assemblages with numerous trochospiral, agglutinated species originally described as Trochammina subvesicularis Hanzlíková. The paper provides a reconsideration of this taxon due to its inconclusive generic status. A new insight into the systematics of trochamminid species is also discussed. A total of 25 samples from Middle Eocene slope marl deposits of the Fore-Magura Unit (from the western part of the Polish Outer Carpathians) were taken for examination. Based on the analysis of 183 specimens recovered from deep-sea mixed foraminiferal assemblages the species is assigned to the genus Ammogloborotalia (Zheng & Fu). The Eocene specimens, named under different generic names and in open nomenclature, similar to the description of Trochammina subvesicularis Hanzlíková, should be referred to the taxonomic name Ammogloborotalia aff. subvesicularis . Similar to modern species of Ammogloborotalia (Zheng & Fu), their Middle Eocene representatives imply a bathyal water depth and good connection of the flysch-type Fore-Magura zone basin with the World Ocean.
{"title":"An updated generic status of Ammogloborotalia aff. subvesicularis (Hanzlíková) from the Middle Eocene deposits of the Fore-Magura Unit (Polish Outer Carpathians)","authors":"Weronika Baliniak","doi":"10.31577/geolcarp.2023.18","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.18","url":null,"abstract":": The Middle Eocene microfauna of the Fore-Magura Unit contains rich foraminiferal assemblages with numerous trochospiral, agglutinated species originally described as Trochammina subvesicularis Hanzlíková. The paper provides a reconsideration of this taxon due to its inconclusive generic status. A new insight into the systematics of trochamminid species is also discussed. A total of 25 samples from Middle Eocene slope marl deposits of the Fore-Magura Unit (from the western part of the Polish Outer Carpathians) were taken for examination. Based on the analysis of 183 specimens recovered from deep-sea mixed foraminiferal assemblages the species is assigned to the genus Ammogloborotalia (Zheng & Fu). The Eocene specimens, named under different generic names and in open nomenclature, similar to the description of Trochammina subvesicularis Hanzlíková, should be referred to the taxonomic name Ammogloborotalia aff. subvesicularis . Similar to modern species of Ammogloborotalia (Zheng & Fu), their Middle Eocene representatives imply a bathyal water depth and good connection of the flysch-type Fore-Magura zone basin with the World Ocean.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"231 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135870908","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}
: The felsic suite in the northern part of the Ditrău Alkaline Massif has previously been considered as a homo - geneous, uniform unit of the igneous complex. However, these felsic rocks exhibit remarkable diversity on the micro-scale. Petrographic observations were complemented by bulk-rock and mineral-scale geochemical data to further support this hypothesis. Whole-rock composition of the studied rocks validates the presence of two, compositionally-different felsic cumulate piles in the massif (characterised by Eu/Eu * = 2.5–6.7, ΣREE = 125–206 ppm and Eu/Eu * = 1.0–1.1, ΣREE = 358–688 ppm, respectively). Mineral chemical data (amphibole, clinopyroxene, and plagioclase) were acquired from crystals of different textural positions (clot-forming and isolated) to understand which of the ferromagnesian minerals and plagioclase have the highest potential for recognising distinct magmatic environments and open-system magmatic processes. The composition of clinopyroxenes (diopside with mg# = 0.77 and 0.85, respectively) overlaps with the formerly published data. Moreover, a new, cumulus-phase occurrence of the clinopyroxenes with a convex REE pattern has been identified. Abrupt changes of Ba, Sr, TiO 2 and ΣREE concentrations in different domains of the zoned amphibole crystals and variations in the MgO, FeO, TiO 2 , Sr, Ba, La, Ce, and anorthite content in plagioclase crystals, together with the bulk-rock data point to the hybrid nature of the majority of the investigated rocks. Our recent geochemical data support the previous, predominantly petrography-based assumptions that the felsic suite in the northern area of the massif was formed in a dynamic, open-system magmatic environment, wherein crystal settling, magma mixing, crystal/mush transfer, and recycling as well as country rock assimilation, prevailed.
{"title":"Bulk-rock and mineral-scale geochemical evidence of open-system magmatic processes in the felsic rocks of the northern part of the Ditrău Alkaline Massif (Eastern Carpathians, Romania)","authors":"Luca Kiri, Máté Szemerédi, Saskia Erdmann, Elemér Pál-Molnár, Anikó Batki","doi":"10.31577/geolcarp.2023.20","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.20","url":null,"abstract":": The felsic suite in the northern part of the Ditrău Alkaline Massif has previously been considered as a homo - geneous, uniform unit of the igneous complex. However, these felsic rocks exhibit remarkable diversity on the micro-scale. Petrographic observations were complemented by bulk-rock and mineral-scale geochemical data to further support this hypothesis. Whole-rock composition of the studied rocks validates the presence of two, compositionally-different felsic cumulate piles in the massif (characterised by Eu/Eu * = 2.5–6.7, ΣREE = 125–206 ppm and Eu/Eu * = 1.0–1.1, ΣREE = 358–688 ppm, respectively). Mineral chemical data (amphibole, clinopyroxene, and plagioclase) were acquired from crystals of different textural positions (clot-forming and isolated) to understand which of the ferromagnesian minerals and plagioclase have the highest potential for recognising distinct magmatic environments and open-system magmatic processes. The composition of clinopyroxenes (diopside with mg# = 0.77 and 0.85, respectively) overlaps with the formerly published data. Moreover, a new, cumulus-phase occurrence of the clinopyroxenes with a convex REE pattern has been identified. Abrupt changes of Ba, Sr, TiO 2 and ΣREE concentrations in different domains of the zoned amphibole crystals and variations in the MgO, FeO, TiO 2 , Sr, Ba, La, Ce, and anorthite content in plagioclase crystals, together with the bulk-rock data point to the hybrid nature of the majority of the investigated rocks. Our recent geochemical data support the previous, predominantly petrography-based assumptions that the felsic suite in the northern area of the massif was formed in a dynamic, open-system magmatic environment, wherein crystal settling, magma mixing, crystal/mush transfer, and recycling as well as country rock assimilation, prevailed.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135871051","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 : 2023-10-31DOI: 10.31577/geolcarp.2023.16
Firat Şengün, Altuğ Hasözbek, Güllü Deniz Doğan-Külahci
: The Tozlu metaophiolite is composed predominantly of metagabbro, banded amphibolite, metadunite, and serpentinite, which are exposed in the Kazdağ Massif located in the northwestern part of Turkey. The geochemistry (major, trace, and rare earth elements) and petrography of the Tozlu metaophiolite in the Kazdağ Massif provided significant knowledge about protolith, petrogenesis, source characteristics and tectonic setting in northwest Turkey. Trace element geochemistry, Ti/Y (29.95–296.92 ppm) and Nb/Y (0.01–0.17 ppm) ratios suggest that metaophiolitic rocks were derived from a tholeiitic magma and igneous protolith of basaltic composition. The immobile trace element tectono-magmatic discrimination diagrams define a mid-ocean ridge basalt (MORB) to volcanic arc (IAT) affinity for the Tozlu metaophiolite. The metaophiolitic rocks demonstrate flat rare earth element (REE) patterns and enrichment of large ion lithophile elements (LILEs; i.e., Rb, Ba, Th), as well as depletion of high field strength elements (HFSEs; i.e., Nb, Th, Ti, Hf). N-MORB characteristics of the Tozlu metaophiolite on a multi-element diagram suggest that the protolith of metaophiolitic rocks generated in a subduction-related setting. The tholeiitic metaophiolitic rocks resulted from the metamorphism of an island arc-type basaltic protolith and display subduction zone components according to the Th/Yb and Ta/Yb ratios. The Tozlu metaophiolite with MORB/IAT affinity witness for supra-subduction zone originated in island arc/back-arc settings.
{"title":"THE GEOCHEMISTRY, ORIGIN AND TECTONIC SETTING OF THE TOZLU METAOPHIOLITE IN THE KAZDAĞ MASSIF (BIGA PENINSULA, NW ANATOLIA)","authors":"Firat Şengün, Altuğ Hasözbek, Güllü Deniz Doğan-Külahci","doi":"10.31577/geolcarp.2023.16","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.16","url":null,"abstract":": The Tozlu metaophiolite is composed predominantly of metagabbro, banded amphibolite, metadunite, and serpentinite, which are exposed in the Kazdağ Massif located in the northwestern part of Turkey. The geochemistry (major, trace, and rare earth elements) and petrography of the Tozlu metaophiolite in the Kazdağ Massif provided significant knowledge about protolith, petrogenesis, source characteristics and tectonic setting in northwest Turkey. Trace element geochemistry, Ti/Y (29.95–296.92 ppm) and Nb/Y (0.01–0.17 ppm) ratios suggest that metaophiolitic rocks were derived from a tholeiitic magma and igneous protolith of basaltic composition. The immobile trace element tectono-magmatic discrimination diagrams define a mid-ocean ridge basalt (MORB) to volcanic arc (IAT) affinity for the Tozlu metaophiolite. The metaophiolitic rocks demonstrate flat rare earth element (REE) patterns and enrichment of large ion lithophile elements (LILEs; i.e., Rb, Ba, Th), as well as depletion of high field strength elements (HFSEs; i.e., Nb, Th, Ti, Hf). N-MORB characteristics of the Tozlu metaophiolite on a multi-element diagram suggest that the protolith of metaophiolitic rocks generated in a subduction-related setting. The tholeiitic metaophiolitic rocks resulted from the metamorphism of an island arc-type basaltic protolith and display subduction zone components according to the Th/Yb and Ta/Yb ratios. The Tozlu metaophiolite with MORB/IAT affinity witness for supra-subduction zone originated in island arc/back-arc settings.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"194 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135870438","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 : 2023-06-30DOI: 10.31577/geolcarp.2023.12
Mehmet Ali Ertürk, H. Kara, A. Sar, İ. Yılmaz, N. Aysal
: The Southeast Anatolian Orogenic Belt (SAOB) consists of various tectono-magmatic and tectono-stratigraphic units such as metamorphic massifs, granitoids, ophiolites and volcanic rocks. In this study, we report new zircon U–Pb LA-ICP-MS ages, Sr–Nd isotope analysis and whole-rock geochemistry from Miocene felsic (dacitic and rhyolitic) rocks cross-cutting the Permo–Triassic Malatya metamorphic complex to determine the source of magmatism and magmatic processes in the region. The zircon U–Pb crystallisation ages are between 16.66 ± 0.23 Ma and 16.83 ± 0.094 Ma, implying the start of the post-collisional volcanism in the Early Miocene (Burdigalian) period. Volcanic rocks have calc-alkaline and high-K calc-alkaline characters. The 87 Sr/ 86 Sr values for the felsic volcanics range between 0.707098 and 0.711703. The initial 143 Nd/ 144 Nd ratios are between 0.512446 and 0.512469, and the εNd values vary from −3.12 to −3.66. The Nd (T DM ) model ages are between 1.05 and 1.13 Ga. Negative εNd values and Nd (T DM ) model ages show great similarities with the Precambrian basement in Turkey, Iran and the Arabian peninsula. Energy-constrained assimilation– fractional crystallisation (EC-AFC) models testing different crustal sources using Sr–Nd isotope data show that primary magmas contain significant crustal melt contributions. Geochemical data indicate that the felsic rocks may have originated from crust-derived melts mixed with lithospheric mantle-derived mafic melts during its residence in the upper crust in a post-collisional tectonic setting.
{"title":"Geochronology and petrogenesis of the lower Miocene felsic rocks: New evidence for initiation of post-collisional magmatism in the SW Malatya – Eastern Anatolia (Turkey)","authors":"Mehmet Ali Ertürk, H. Kara, A. Sar, İ. Yılmaz, N. Aysal","doi":"10.31577/geolcarp.2023.12","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.12","url":null,"abstract":": The Southeast Anatolian Orogenic Belt (SAOB) consists of various tectono-magmatic and tectono-stratigraphic units such as metamorphic massifs, granitoids, ophiolites and volcanic rocks. In this study, we report new zircon U–Pb LA-ICP-MS ages, Sr–Nd isotope analysis and whole-rock geochemistry from Miocene felsic (dacitic and rhyolitic) rocks cross-cutting the Permo–Triassic Malatya metamorphic complex to determine the source of magmatism and magmatic processes in the region. The zircon U–Pb crystallisation ages are between 16.66 ± 0.23 Ma and 16.83 ± 0.094 Ma, implying the start of the post-collisional volcanism in the Early Miocene (Burdigalian) period. Volcanic rocks have calc-alkaline and high-K calc-alkaline characters. The 87 Sr/ 86 Sr values for the felsic volcanics range between 0.707098 and 0.711703. The initial 143 Nd/ 144 Nd ratios are between 0.512446 and 0.512469, and the εNd values vary from −3.12 to −3.66. The Nd (T DM ) model ages are between 1.05 and 1.13 Ga. Negative εNd values and Nd (T DM ) model ages show great similarities with the Precambrian basement in Turkey, Iran and the Arabian peninsula. Energy-constrained assimilation– fractional crystallisation (EC-AFC) models testing different crustal sources using Sr–Nd isotope data show that primary magmas contain significant crustal melt contributions. Geochemical data indicate that the felsic rocks may have originated from crust-derived melts mixed with lithospheric mantle-derived mafic melts during its residence in the upper crust in a post-collisional tectonic setting.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48225532","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 : 2023-06-30DOI: 10.31577/geolcarp.2023.14
Z. Kovács, Z. Horváth-Kostka, T. Müller, J. Pálfy
: Many localities worldwide yielded rich Toarcian (Early Jurassic) ammonoid faunas whose diversity history enhanced our understanding of global events and their geographic distribution aided paleogeographic and paleoceano-graphic reconstructions. However, major differences remain in the intensity of studies as some areas have received significantly less attention, yet their study would improve regional and global correlations and reconstructions. The Toarcian faunas of the Mecsek Mts (SW Hungary) represented one such knowledge gap that is filled herein on the basis of the large Hetényi Collection and other material, totaling more than 5000 specimens. The Toarcian Ammonitina assemblages are outlined, documenting the occurrence of 43 species, of which 14 stratigraphically important species are described systematically. The studied assemblages bear a close affinity to the NW European faunal province, hence the standard ammonite chronostratigraphic scale is conveniently applicable for subdividing the Toarcian sequence of the Mecsek Mts. All of the Toarcian zones and most subzones are documented by their index taxa and the ranges established from NW European localities allow chronostratigraphic assignment of the ammonite-bearing localities in the Mecsek Mts. A comparison with other coeval faunas from the widespread spotted marl facies reveals that taxon richness here is comparable with that recorded from other parts of the Tisza Mega-Unit in the Apuşeni Mts and the Eastern Carpathians in Romania. Temporal patterns of diversity changes, with peaks in the Bifrons and Thouarsense zones, may be interpreted in the framework of biotic changes in the aftermath of the Jenkyns Event.
{"title":"Chronostratigraphic overview of the Toarcian (Early Jurassic) ammonite fauna from the Mecsek Mountains (Hungary)","authors":"Z. Kovács, Z. Horváth-Kostka, T. Müller, J. Pálfy","doi":"10.31577/geolcarp.2023.14","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.14","url":null,"abstract":": Many localities worldwide yielded rich Toarcian (Early Jurassic) ammonoid faunas whose diversity history enhanced our understanding of global events and their geographic distribution aided paleogeographic and paleoceano-graphic reconstructions. However, major differences remain in the intensity of studies as some areas have received significantly less attention, yet their study would improve regional and global correlations and reconstructions. The Toarcian faunas of the Mecsek Mts (SW Hungary) represented one such knowledge gap that is filled herein on the basis of the large Hetényi Collection and other material, totaling more than 5000 specimens. The Toarcian Ammonitina assemblages are outlined, documenting the occurrence of 43 species, of which 14 stratigraphically important species are described systematically. The studied assemblages bear a close affinity to the NW European faunal province, hence the standard ammonite chronostratigraphic scale is conveniently applicable for subdividing the Toarcian sequence of the Mecsek Mts. All of the Toarcian zones and most subzones are documented by their index taxa and the ranges established from NW European localities allow chronostratigraphic assignment of the ammonite-bearing localities in the Mecsek Mts. A comparison with other coeval faunas from the widespread spotted marl facies reveals that taxon richness here is comparable with that recorded from other parts of the Tisza Mega-Unit in the Apuşeni Mts and the Eastern Carpathians in Romania. Temporal patterns of diversity changes, with peaks in the Bifrons and Thouarsense zones, may be interpreted in the framework of biotic changes in the aftermath of the Jenkyns Event.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46592461","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 : 2023-06-30DOI: 10.31577/geolcarp.2023.13
J. Rez, Markéta Kernstocková, Vít Baldík
: Data from three quarries in the southern Moravian Karst (SE Czech Republic), namely fault-slip data and calcite twinning data, enabled a side-to-side comparison of two paleostress analysis techniques. TwinCalc (www.eltekto.cz) was used to analyse 8 samples of calcite veins, yielding 20 stress states and MARK was used to analyse the fault-slip data yielding 10 stress states. 26 out of these 30 stress tensors were sorted into four stress phases (P1–P4) using a stress tensor similarity cluster analysis based on angles between stress tensor 9D vectors. The oldest phase is P4 – N–S trending compression. P1 is younger, and responsible for the reactivation of NW–SE striking dextral strike-slip faults. Both are post-Cretaceous pre-Langhian phases. The second-to-last phase is P3 associated with WNW–ESE striking mostly normal faults. This stress state had been active during the Miocene before the Tortonian P2 phase. The last phase is the Tortonian P2 phase, which is characterised by NNE–SSW striking dextral strike-slip faulting.
{"title":"Stress analysis from the southern part of Moravian Karst (Czech Republic)","authors":"J. Rez, Markéta Kernstocková, Vít Baldík","doi":"10.31577/geolcarp.2023.13","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.13","url":null,"abstract":": Data from three quarries in the southern Moravian Karst (SE Czech Republic), namely fault-slip data and calcite twinning data, enabled a side-to-side comparison of two paleostress analysis techniques. TwinCalc (www.eltekto.cz) was used to analyse 8 samples of calcite veins, yielding 20 stress states and MARK was used to analyse the fault-slip data yielding 10 stress states. 26 out of these 30 stress tensors were sorted into four stress phases (P1–P4) using a stress tensor similarity cluster analysis based on angles between stress tensor 9D vectors. The oldest phase is P4 – N–S trending compression. P1 is younger, and responsible for the reactivation of NW–SE striking dextral strike-slip faults. Both are post-Cretaceous pre-Langhian phases. The second-to-last phase is P3 associated with WNW–ESE striking mostly normal faults. This stress state had been active during the Miocene before the Tortonian P2 phase. The last phase is the Tortonian P2 phase, which is characterised by NNE–SSW striking dextral strike-slip faulting.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43298087","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 : 2023-06-30DOI: 10.31577/geolcarp.2023.11
Raouf Ghribi, Hassène Affouri, S. Bouaziz
: The tectonic inversion of the Miocene extensional basins (Cap Bon Peninsula–Sahel area, northeastern Tunisia) is an important process that accommodates the crustal shortening in the northeastern Tunisian edge with the ongoing collision between the African and European plates. Field observations and microtectonic measurements have revealed two main Late Miocene tectonic events: (1) A NE–SW trending extensional tectonic event that would create titled blocks, horsts, and grabens, as well as slump features. These structures were controlled by numerous conjugate systems of syndepositional normal faults. On a regional scale, the NW-trending faults controlled the Miocene sedimentation and subsidence rate in the Takelsa, Dakhla, Saouaf, and Zeramdine syn-rift grabens and (2) the NW-directed post-Tortonian compression, the so-called “Alpine/Atlasic event” that was identified by NE–SW-oriented reverse slip movements and associated folds. The latter compressional event began in the latest Miocene and continued through the Plio–Quaternary, which thus led to the complete inversion of the Miocene basins by the ongoing African and European plates’ convergence. A significant neotectonic uplift of the Abderrahmane, Korbus, and Skanes areas recorded the switch from Late Miocene crustal extension to post-Tortonian to Quaternary compressional tectonics. In fact, the present-day petroleum trap configuration of the northeastern offshore Tunisia is highly controlled to the Miocene–Quaternary tectonic inversion. The sandy levels along the thick Tortonian section provided the most preferred target for petroleum exploration. They exhibit considerable variations in thickness controlled by Late Miocene to Quaternary tectonic trends.
{"title":"Tectonic inversion of Late Miocene extensional deformations in northeastern Tunisia (Cap Bon Peninsula–Sahel area)","authors":"Raouf Ghribi, Hassène Affouri, S. Bouaziz","doi":"10.31577/geolcarp.2023.11","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.11","url":null,"abstract":": The tectonic inversion of the Miocene extensional basins (Cap Bon Peninsula–Sahel area, northeastern Tunisia) is an important process that accommodates the crustal shortening in the northeastern Tunisian edge with the ongoing collision between the African and European plates. Field observations and microtectonic measurements have revealed two main Late Miocene tectonic events: (1) A NE–SW trending extensional tectonic event that would create titled blocks, horsts, and grabens, as well as slump features. These structures were controlled by numerous conjugate systems of syndepositional normal faults. On a regional scale, the NW-trending faults controlled the Miocene sedimentation and subsidence rate in the Takelsa, Dakhla, Saouaf, and Zeramdine syn-rift grabens and (2) the NW-directed post-Tortonian compression, the so-called “Alpine/Atlasic event” that was identified by NE–SW-oriented reverse slip movements and associated folds. The latter compressional event began in the latest Miocene and continued through the Plio–Quaternary, which thus led to the complete inversion of the Miocene basins by the ongoing African and European plates’ convergence. A significant neotectonic uplift of the Abderrahmane, Korbus, and Skanes areas recorded the switch from Late Miocene crustal extension to post-Tortonian to Quaternary compressional tectonics. In fact, the present-day petroleum trap configuration of the northeastern offshore Tunisia is highly controlled to the Miocene–Quaternary tectonic inversion. The sandy levels along the thick Tortonian section provided the most preferred target for petroleum exploration. They exhibit considerable variations in thickness controlled by Late Miocene to Quaternary tectonic trends.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44827232","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 : 2023-06-30DOI: 10.31577/geolcarp.2023.15
Katarína Kriváňová, R. Vojtko, David Miloš Droppa, Silvia Gerátová
: The Nízke Tatry Mts. is a mountain range located in the central part of the Western Carpathians. Throughout history, the studied area has been affected by at least two orogenetic cycles – Variscan and Alpine. Based on structural analyses, it is possible to determine several deformation events. The older deformations ( D V ), which were accompanied by the Variscan higher-grade metamorphism, are characterised by penetrative tectonic foliations, such as schistosity and gneissic banding, and go hand in hand with folds and lineations. In contrast, the younger deformations ( D A ) are marked by structural evolution under low-grade (retrograde) metamorphism, phyllitic foliations, crenulation foliation, cataclasis, and minor recrystallisation. The Variscan deformation ( D 2 V ) is the earliest pervasive deformation with pronounced evolution of S 2 V metamorphic foliation, locally with preserved isoclinal and rootless folds of S 1 V planar fabric. Stretching and mineral lineations ( L 2 V ) are usually oriented in the ENE–WSW direction. The fabric of D 2 V is intensively affected by folds ( F 3 V ) and, in many places, marked by development of S 3 V axial planes. The Alpine deformation ( D 1 A ) was accompanied by low-grade metamorphism and depicted by space to zonal with pervasive foliation ( S 1 A ) in some areas. This deformation is characterised by a typical crenulation cleavage, where S 2 V planes are folded and produced S 1 A foliation. The crenulation and intersection lineations ( L 1 cA ) have NE–SW to E–W trends. The D 1 A deformation is also accompanied by pronounced evolution of NNW–SSE groove, stretching, and mineral lineation ( L 1 tA ). Shortening in the NNW–SSE direction is also evidenced by asymmetric folds with an ENE–WSW orientation of fold axes ( F 1 A ) and line intersections ( L 1 cA ) with pronounced top-to-the-NNW tectonic transport. The youngest observed Alpine deformation ( D 2 A ) is related to an extension of the Tatric crystalline basement with top-to-the-east transport defined by Alpine lineations ( L 2 A ) on spaced planar structures ( S 2 A ) and correspond to C surfaces.
{"title":"Deformation record and revised tectonic evolution of the Nízke Tatry Mts. in the Tatric – Veporic junction area: Insights from structural analysis","authors":"Katarína Kriváňová, R. Vojtko, David Miloš Droppa, Silvia Gerátová","doi":"10.31577/geolcarp.2023.15","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.15","url":null,"abstract":": The Nízke Tatry Mts. is a mountain range located in the central part of the Western Carpathians. Throughout history, the studied area has been affected by at least two orogenetic cycles – Variscan and Alpine. Based on structural analyses, it is possible to determine several deformation events. The older deformations ( D V ), which were accompanied by the Variscan higher-grade metamorphism, are characterised by penetrative tectonic foliations, such as schistosity and gneissic banding, and go hand in hand with folds and lineations. In contrast, the younger deformations ( D A ) are marked by structural evolution under low-grade (retrograde) metamorphism, phyllitic foliations, crenulation foliation, cataclasis, and minor recrystallisation. The Variscan deformation ( D 2 V ) is the earliest pervasive deformation with pronounced evolution of S 2 V metamorphic foliation, locally with preserved isoclinal and rootless folds of S 1 V planar fabric. Stretching and mineral lineations ( L 2 V ) are usually oriented in the ENE–WSW direction. The fabric of D 2 V is intensively affected by folds ( F 3 V ) and, in many places, marked by development of S 3 V axial planes. The Alpine deformation ( D 1 A ) was accompanied by low-grade metamorphism and depicted by space to zonal with pervasive foliation ( S 1 A ) in some areas. This deformation is characterised by a typical crenulation cleavage, where S 2 V planes are folded and produced S 1 A foliation. The crenulation and intersection lineations ( L 1 cA ) have NE–SW to E–W trends. The D 1 A deformation is also accompanied by pronounced evolution of NNW–SSE groove, stretching, and mineral lineation ( L 1 tA ). Shortening in the NNW–SSE direction is also evidenced by asymmetric folds with an ENE–WSW orientation of fold axes ( F 1 A ) and line intersections ( L 1 cA ) with pronounced top-to-the-NNW tectonic transport. The youngest observed Alpine deformation ( D 2 A ) is related to an extension of the Tatric crystalline basement with top-to-the-east transport defined by Alpine lineations ( L 2 A ) on spaced planar structures ( S 2 A ) and correspond to C surfaces.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43077711","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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