Anisian Muschelkalk carbonates of the southern Germanic Basin containing silicified ooidal grainstone are interpreted as evidence of changing pH conditions triggered by increased bioproductivity (marine phytoplankton) and terrestrial input of plant debris during maximum flooding. Three distinct stages of calcite ooid replacement by silica were detected. Stage 1 reflects authigenic quartz development during the growth of the ooids, suggesting a change in the pH–temperature regime of the depositional environment. Stages 2 and 3 are found in silica-rich domains. The composition of silica-rich ooids shows significant Al2O3 and SrO but no FeO and MnO, indicating that late diagenetic alteration was minor. Silicified interparticle pore space is characterized by excellent preservation of marine prasinophytes; palynological slides show high abundance of terrestrial phytoclasts. The implications of our findings for basin dynamics reach from paleogeography to cyclostratigraphy and sequence stratigraphy, since change...
{"title":"Silicification and organic matter preservation in the Anisian Muschelkalk: Implications for the basin dynamics of the central European Muschelkalk Sea","authors":"A. Götz, M. Montenari, G. Costin","doi":"10.1556/24.60.2017.002","DOIUrl":"https://doi.org/10.1556/24.60.2017.002","url":null,"abstract":"Anisian Muschelkalk carbonates of the southern Germanic Basin containing silicified ooidal grainstone are interpreted as evidence of changing pH conditions triggered by increased bioproductivity (marine phytoplankton) and terrestrial input of plant debris during maximum flooding. Three distinct stages of calcite ooid replacement by silica were detected. Stage 1 reflects authigenic quartz development during the growth of the ooids, suggesting a change in the pH–temperature regime of the depositional environment. Stages 2 and 3 are found in silica-rich domains. The composition of silica-rich ooids shows significant Al2O3 and SrO but no FeO and MnO, indicating that late diagenetic alteration was minor. Silicified interparticle pore space is characterized by excellent preservation of marine prasinophytes; palynological slides show high abundance of terrestrial phytoclasts. The implications of our findings for basin dynamics reach from paleogeography to cyclostratigraphy and sequence stratigraphy, since change...","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"60 1","pages":"35-52"},"PeriodicalIF":0.0,"publicationDate":"2017-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1556/24.60.2017.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44309985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Demény, A. Németh, Z. Kern, G. Czuppon, M. Molnár, S. Leél-Őssy, M. Óvári, J. Stieber
Determination of the long-term behavior of cave systems and their response to changing environmental conditions is essential for further paleoclimate analyses of cave-hosted carbonate deposits. For this purpose, four actively forming stalagmites were collected in the Baradla Cave where a three-year monitoring campaign was also conducted. Based on textural characteristics and radiocarbon analyses, the stalagmites are composed of annual laminae, whose counting was used to establish age–depth relationships. Fast and slowly growing stalagmites have different stable carbon and oxygen isotope compositions as well as trace element contents that could be attributed to differences in drip water migration pathways. The stable isotope compositions were compared with meteorological data of the last ∼100 years indicating that carbon isotope compositions of the stalagmites may reflect changes in precipitation amount, while oxygen isotope compositions are more related to temperature variations. The combined textural–geo...
{"title":"Recently forming stalagmites from the Baradla Cave and their suitability assessment for climate-proxy relationships","authors":"A. Demény, A. Németh, Z. Kern, G. Czuppon, M. Molnár, S. Leél-Őssy, M. Óvári, J. Stieber","doi":"10.1556/24.60.2017.001","DOIUrl":"https://doi.org/10.1556/24.60.2017.001","url":null,"abstract":"Determination of the long-term behavior of cave systems and their response to changing environmental conditions is essential for further paleoclimate analyses of cave-hosted carbonate deposits. For this purpose, four actively forming stalagmites were collected in the Baradla Cave where a three-year monitoring campaign was also conducted. Based on textural characteristics and radiocarbon analyses, the stalagmites are composed of annual laminae, whose counting was used to establish age–depth relationships. Fast and slowly growing stalagmites have different stable carbon and oxygen isotope compositions as well as trace element contents that could be attributed to differences in drip water migration pathways. The stable isotope compositions were compared with meteorological data of the last ∼100 years indicating that carbon isotope compositions of the stalagmites may reflect changes in precipitation amount, while oxygen isotope compositions are more related to temperature variations. The combined textural–geo...","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"60 1","pages":"1-34"},"PeriodicalIF":0.0,"publicationDate":"2017-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1556/24.60.2017.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42010788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Vető, K. Báldi, S. Ćorić, M. Hetényi, A. Demény, I. Futó
This study is intended to clarify the depositional environment of a 180-m-thick, immature, limy Middle Miocene oil source rock interval, cored in the Zala Basin, western Hungary. For this purpose, a highly interdisciplinary approach was applied combining simple, standard micropaleontological, isotopic, and organic geochemical methods, rarely applied together. Foraminifera were studied for estimating bottom oxygenation and water depth, while nannoplankton biostratigraphy permitted for estimating the rate of sedimentation. The studied source rocks were deposited in a rather shallow sea, below well-oxygenated bottom water. The abundant epiphytic foraminiferal fauna proves that the bottom was densely inhabited by benthic algae, while the high δ13Corg (>–22‰) clearly indicates massive benthic algal contribution to the kerogen. Mass accumulation rate of the limy upper part of the NN5 nannoplankton biozone, the oil source interval included, was very high (551 t/m2/Ma). In spite of moderate productivity and good ...
{"title":"Benthic algae as major precursors of oil-prone kerogen – A case study from the Hungarian Middle Miocene","authors":"I. Vető, K. Báldi, S. Ćorić, M. Hetényi, A. Demény, I. Futó","doi":"10.1556/24.59.2016.004","DOIUrl":"https://doi.org/10.1556/24.59.2016.004","url":null,"abstract":"This study is intended to clarify the depositional environment of a 180-m-thick, immature, limy Middle Miocene oil source rock interval, cored in the Zala Basin, western Hungary. For this purpose, a highly interdisciplinary approach was applied combining simple, standard micropaleontological, isotopic, and organic geochemical methods, rarely applied together. Foraminifera were studied for estimating bottom oxygenation and water depth, while nannoplankton biostratigraphy permitted for estimating the rate of sedimentation. The studied source rocks were deposited in a rather shallow sea, below well-oxygenated bottom water. The abundant epiphytic foraminiferal fauna proves that the bottom was densely inhabited by benthic algae, while the high δ13Corg (>–22‰) clearly indicates massive benthic algal contribution to the kerogen. Mass accumulation rate of the limy upper part of the NN5 nannoplankton biozone, the oil source interval included, was very high (551 t/m2/Ma). In spite of moderate productivity and good ...","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"59 1","pages":"87-107"},"PeriodicalIF":0.0,"publicationDate":"2016-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1556/24.59.2016.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67002355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The pre-Cenozoic basement of central Hungary is partly made up of different types of carbonate rocks. These carbonates are often good hydrocarbon reservoirs, and hydrocarbon production is significant in this region in Hungary. Nonetheless, the petrography of the reservoir rocks has not yet been investigated in detail. In this study, the results of the investigations of the lithology of a carbonate hydrocarbon reservoir from central Hungary (Gomba Field) are presented. Based on this work, two types of pure limestone, a dolomitic limestone and a polymictic breccia, could be distinguished in the study area. The limestone types are similar to the Kisfennsik Limestone Member and the Berva Limestone of the Bukk Mountains, but they contain significant amounts of framboidal pyrite and dead oil as vein fillings. The breccia is predominantly composed of angular carbonate clasts and minor metamorphic and sedimentary rock fragments in a chaotic pattern. The breccia has some grains that may be speleothems (e.g., stala...
{"title":"Petrology and paleokarst features of the Gomba hydrocarbon reservoir (central Hungary)","authors":"M. Bauer, T. Tóth, B. Raucsik, István Garaguly","doi":"10.1556/24.59.2016.003","DOIUrl":"https://doi.org/10.1556/24.59.2016.003","url":null,"abstract":"The pre-Cenozoic basement of central Hungary is partly made up of different types of carbonate rocks. These carbonates are often good hydrocarbon reservoirs, and hydrocarbon production is significant in this region in Hungary. Nonetheless, the petrography of the reservoir rocks has not yet been investigated in detail. In this study, the results of the investigations of the lithology of a carbonate hydrocarbon reservoir from central Hungary (Gomba Field) are presented. Based on this work, two types of pure limestone, a dolomitic limestone and a polymictic breccia, could be distinguished in the study area. The limestone types are similar to the Kisfennsik Limestone Member and the Berva Limestone of the Bukk Mountains, but they contain significant amounts of framboidal pyrite and dead oil as vein fillings. The breccia is predominantly composed of angular carbonate clasts and minor metamorphic and sedimentary rock fragments in a chaotic pattern. The breccia has some grains that may be speleothems (e.g., stala...","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"59 1","pages":"28-59"},"PeriodicalIF":0.0,"publicationDate":"2016-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1556/24.59.2016.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67002572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mantle peridotites are interpreted as either residues after partial melting and melt extraction or products of igneous refertilization of refractory peridotites. The simple distinction between these models is difficult to assess because in chemical variation diagrams, both processes lead essentially to the same results. The only exception is the Ti-in-Cpx versus Ti-in-whole-rock plots, which can successfully discriminate between these models. In this study, a modified version of Ti-in-Cpx versus Mg#-in-olivine plots was applied to ∼1,500 spinel peridotite xenoliths from worldwide localities. The results showed that the vast majority of shallow mantle samples are consistent with the partial melting model; however, a minority of samples may indicate refertilization of formerly refractory mantle domains.
地幔橄榄岩可以解释为部分熔融和熔融萃取后的残余物，也可以解释为难熔橄榄岩火成岩再作用的产物。这些模型之间的简单区别很难评估，因为在化学变化图中，两种过程基本上导致相同的结果。唯一的例外是cpx中的ti和整块岩石中的ti图，它们可以成功地区分这些模型。在这项研究中，一种改良版的Ti-in-Cpx和Mg - In -橄榄石地块被应用于来自世界各地的约1500个尖晶石橄榄岩捕虏体。结果表明，绝大多数浅层地幔样品符合部分熔融模式;然而，少数样品可能表明以前难熔的地幔域的再作用。
{"title":"The role of melt depletion versus refertilization in the major element chemistry of four-phase spinel peridotite xenoliths","authors":"A. Embey-Isztin","doi":"10.1556/24.59.2016.002","DOIUrl":"https://doi.org/10.1556/24.59.2016.002","url":null,"abstract":"Mantle peridotites are interpreted as either residues after partial melting and melt extraction or products of igneous refertilization of refractory peridotites. The simple distinction between these models is difficult to assess because in chemical variation diagrams, both processes lead essentially to the same results. The only exception is the Ti-in-Cpx versus Ti-in-whole-rock plots, which can successfully discriminate between these models. In this study, a modified version of Ti-in-Cpx versus Mg#-in-olivine plots was applied to ∼1,500 spinel peridotite xenoliths from worldwide localities. The results showed that the vast majority of shallow mantle samples are consistent with the partial melting model; however, a minority of samples may indicate refertilization of formerly refractory mantle domains.","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"59 1","pages":"60-86"},"PeriodicalIF":0.0,"publicationDate":"2016-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1556/24.59.2016.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67002535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Zagros Orogenic Belt includes the Fold and Thrust Belt, the High Zagros Belt, the Outer Zagros Ophiolitic Belt, the Sanandaj–Sirjan Metamorphic Belt, the Inner Zagros Ophiolitic Belt, and the Urumieh–Dokhtar Magmatic Belt. We divide the High Zagros evolutionary history into five stages: (1) triple junction formation, (2) continental lithosphere rifting, (3) generation, spreading, and maturation of the Neotethys Ocean, (4) subduction of the oceanic lithosphere, and (5) collision. The Neotethys triple junction, located at the southeastern corner of the Arabian Plate, formed during the Late Silurian–Early Carboniferous. Subsequently, this triple junction became a rift basin due to normal faulting and basalt eruption. The rifting stage occurred during the Late Carboniferous–Early Permian. Thereafter, extension of the basin continued, leading to spreading and maturation of the Neotethys oceanic basin during the Late Permian–Late Triassic. Probably at the end of the Late Triassic, closure of the Paleotethys...
{"title":"Tectonic evolution of the Zagros Orogen in the realm of the Neotethys between the Central Iran and Arabian Plates: An ophiolite perspective","authors":"M. S. Ajirlu, M. Moazzen, R. Hajialioghli","doi":"10.1556/24.59.2016.001","DOIUrl":"https://doi.org/10.1556/24.59.2016.001","url":null,"abstract":"The Zagros Orogenic Belt includes the Fold and Thrust Belt, the High Zagros Belt, the Outer Zagros Ophiolitic Belt, the Sanandaj–Sirjan Metamorphic Belt, the Inner Zagros Ophiolitic Belt, and the Urumieh–Dokhtar Magmatic Belt. We divide the High Zagros evolutionary history into five stages: (1) triple junction formation, (2) continental lithosphere rifting, (3) generation, spreading, and maturation of the Neotethys Ocean, (4) subduction of the oceanic lithosphere, and (5) collision. The Neotethys triple junction, located at the southeastern corner of the Arabian Plate, formed during the Late Silurian–Early Carboniferous. Subsequently, this triple junction became a rift basin due to normal faulting and basalt eruption. The rifting stage occurred during the Late Carboniferous–Early Permian. Thereafter, extension of the basin continued, leading to spreading and maturation of the Neotethys oceanic basin during the Late Permian–Late Triassic. Probably at the end of the Late Triassic, closure of the Paleotethys...","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"59 1","pages":"1-27"},"PeriodicalIF":0.0,"publicationDate":"2016-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1556/24.59.2016.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67002519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Sarapaa, N. Kärkkäinen, Timo Ahtola, Thair Al-Ani
This article evaluates the known rare earth elements (REE), Ti and Li occurrences and exploration potential in Finland, based on existing data combined with new geochemistry and mineralogy, heavy mineral studies, geophysical measurements, geologic mapping and recent drilling of new targets. The potential rock types for REE include carbonatite (Sokli, Korsnas), alkaline rocks (Otanmaki, Lamujarvi, and Iivaara), rapakivi granite and pegmatite (Kovela), and kaolin-bearing weathering crusts in eastern and northern Finland. The highest REE concentrations occur in late magmatic carbonatite veins in the fenite area of the Sokli carbonatite complex. Detailed mineralogical investigations have revealed three distinct types of REE mineralization as phosphates, carbonates and silicates in the studied areas. Mineralogical and mineral chemical evidence demonstrates that hydrothermal processes are responsible for the REE mineralization in the studied rocks and confirms that such processes are predominant in the formatio...
{"title":"High-tech metal potential in Finland with emphasis on rare earth elements (REE), titanium and lithium","authors":"O. Sarapaa, N. Kärkkäinen, Timo Ahtola, Thair Al-Ani","doi":"10.1556/24.58.2015.4.1","DOIUrl":"https://doi.org/10.1556/24.58.2015.4.1","url":null,"abstract":"This article evaluates the known rare earth elements (REE), Ti and Li occurrences and exploration potential in Finland, based on existing data combined with new geochemistry and mineralogy, heavy mineral studies, geophysical measurements, geologic mapping and recent drilling of new targets. The potential rock types for REE include carbonatite (Sokli, Korsnas), alkaline rocks (Otanmaki, Lamujarvi, and Iivaara), rapakivi granite and pegmatite (Kovela), and kaolin-bearing weathering crusts in eastern and northern Finland. The highest REE concentrations occur in late magmatic carbonatite veins in the fenite area of the Sokli carbonatite complex. Detailed mineralogical investigations have revealed three distinct types of REE mineralization as phosphates, carbonates and silicates in the studied areas. Mineralogical and mineral chemical evidence demonstrates that hydrothermal processes are responsible for the REE mineralization in the studied rocks and confirms that such processes are predominant in the formatio...","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"58 1","pages":"291-305"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1556/24.58.2015.4.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67002369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Gyollai, S. Bérczi, K. Fintor, S. Nagy, A. Gucsik
The Mocs chondrite was studied by optical microscopy, element mapping, as well as scanning electron microscope backscattered electron (SEM—BSE) imaging, in order to gain a better understanding of the thermal metamorphic as well as post-shock annealing evolution and the mineralogical signatures in this meteorite. The studied thin section of Mocs meteorite contains 26 chondrules with a variety of chondrule textures, which are characterized by a blurry rim. The chondrules mostly consist of pyroxene and olivine, whereas feldspars occur only in the recrystallized groundmass, chondrule mesostasis, and mineral melt inside and beyond the shock veins. It was found that the matrix was completely recrystallized. According to the scanning electron microscope and optical microscope observations mentioned above, it can be concluded that the Mocs chondrite is a 6.5 petrographic type.
{"title":"Thermal metamorphism of the Mócs meteorite (L6) revealed by optical microscopy and BSE imaging","authors":"I. Gyollai, S. Bérczi, K. Fintor, S. Nagy, A. Gucsik","doi":"10.1556/24.58.2015.4.3","DOIUrl":"https://doi.org/10.1556/24.58.2015.4.3","url":null,"abstract":"The Mocs chondrite was studied by optical microscopy, element mapping, as well as scanning electron microscope backscattered electron (SEM—BSE) imaging, in order to gain a better understanding of the thermal metamorphic as well as post-shock annealing evolution and the mineralogical signatures in this meteorite. The studied thin section of Mocs meteorite contains 26 chondrules with a variety of chondrule textures, which are characterized by a blurry rim. The chondrules mostly consist of pyroxene and olivine, whereas feldspars occur only in the recrystallized groundmass, chondrule mesostasis, and mineral melt inside and beyond the shock veins. It was found that the matrix was completely recrystallized. According to the scanning electron microscope and optical microscope observations mentioned above, it can be concluded that the Mocs chondrite is a 6.5 petrographic type.","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"58 1","pages":"321-333"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1556/24.58.2015.4.3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67002413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper provides information on the mechanical properties of granitic rocks that were subjected to heat. Two types of granitic rocks were tested under laboratory conditions at temperatures of 23 °C, 300 °C and 600 °C. The granitic rock from Bataapati (Moragy Granite) is a pinkish leucocratic monzogranitic type while the second type is grey granite from Mauthausen (Austria). The samples were placed in furnace and temperature raised to 300 °C. Other set of samples were heated to 600 °C. Mechanical tests were performed on non-heated and heated samples and the test results were compared. Heating to 300 °C caused a slight increase in the uniaxial compressive strength and in indirect tensile strength, with reference to the samples kept at 23 °C. A drastic drop in both values was observed when samples were heated to 600 °C. The density of the samples did not show a major change up to 300 °C. On the contrary, a decrease in ultrasonic pulse velocity was observed, with an additional significant loss when samples ...
{"title":"The effect of temperature on the strength of two different granites","authors":"A. Török, Á. Török","doi":"10.1556/24.58.2015.4.5","DOIUrl":"https://doi.org/10.1556/24.58.2015.4.5","url":null,"abstract":"The paper provides information on the mechanical properties of granitic rocks that were subjected to heat. Two types of granitic rocks were tested under laboratory conditions at temperatures of 23 °C, 300 °C and 600 °C. The granitic rock from Bataapati (Moragy Granite) is a pinkish leucocratic monzogranitic type while the second type is grey granite from Mauthausen (Austria). The samples were placed in furnace and temperature raised to 300 °C. Other set of samples were heated to 600 °C. Mechanical tests were performed on non-heated and heated samples and the test results were compared. Heating to 300 °C caused a slight increase in the uniaxial compressive strength and in indirect tensile strength, with reference to the samples kept at 23 °C. A drastic drop in both values was observed when samples were heated to 600 °C. The density of the samples did not show a major change up to 300 °C. On the contrary, a decrease in ultrasonic pulse velocity was observed, with an additional significant loss when samples ...","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"58 1","pages":"356-369"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1556/24.58.2015.4.5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67002448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sideritic—kaolinitic and green clay layers were previously reported from the Mecsek Mountains (SW Hungary) as indicators of Tethyan volcanism in the otherwise germanotype Middle Triassic succession. The aim of the present study is to provide a review and a critical re-evaluation of the previously published data on both the sideritic—kaolinitic layers (the so-called “Manfa Siderite”) and the green clay layers. New results of mineralogical investigation of the green clay layers are also presented. The Middle Triassic volcanic origin of the “Manfa Siderite” cannot be confirmed. In addition to a possible volcanic contribution, the sideritic—kaolinitic layers were probably formed in a freshwater swamp under humid, tropical climatic conditions, whereby weathering in an organic-rich, acidic environment led to the formation of “underclays” and siderite in the coal-bearing formations of Late Triassic to Early Jurassic age. These layers were probably tectonically placed over Middle Triassic carbonates. The illitic ...
{"title":"Sideritic—kaolinitic and green clay layers in the Mecsek Mountains (SW Hungary): Indicators of Middle Triassic volcanism—Myth or reality?","authors":"G. Lukoczki, Tamás Budai, T. Németh","doi":"10.1556/24.58.2015.4.4","DOIUrl":"https://doi.org/10.1556/24.58.2015.4.4","url":null,"abstract":"Sideritic—kaolinitic and green clay layers were previously reported from the Mecsek Mountains (SW Hungary) as indicators of Tethyan volcanism in the otherwise germanotype Middle Triassic succession. The aim of the present study is to provide a review and a critical re-evaluation of the previously published data on both the sideritic—kaolinitic layers (the so-called “Manfa Siderite”) and the green clay layers. New results of mineralogical investigation of the green clay layers are also presented. The Middle Triassic volcanic origin of the “Manfa Siderite” cannot be confirmed. In addition to a possible volcanic contribution, the sideritic—kaolinitic layers were probably formed in a freshwater swamp under humid, tropical climatic conditions, whereby weathering in an organic-rich, acidic environment led to the formation of “underclays” and siderite in the coal-bearing formations of Late Triassic to Early Jurassic age. These layers were probably tectonically placed over Middle Triassic carbonates. The illitic ...","PeriodicalId":39930,"journal":{"name":"Central European Geology","volume":"58 1","pages":"334-355"},"PeriodicalIF":0.0,"publicationDate":"2015-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67002429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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