Pub Date : 2021-01-01DOI: 10.31577/geolcarp.72.2.4
Jozef Madzin, E. Márton, D. Starek, T. Mikuš
Anisotropy of magnetic susceptibility and anisotropy of anhysteretic remanent magnetization were studied in the Oligocene turbidites of the weakly deformed Central Carpathian Paleogene Basin. In order to decide whether the magnetic fabric can be related to deposition from a paleoflow or to incipient weak tectonic deformation we compared magnetic fabrics in individual intervals of the Bouma sequence with sedimentary structures and tectonic brittle mesostructures (joints). In the Ta–Te intervals we observed a good correlation between maximum susceptibility axes and SW(W)–NE(E) oriented paleoflows. Within convoluted and slump folded sandstones the AMS fabric coincides with the orientation of soft-sediment deformation structures. These features suggest the sedimentary origin of the AMS fabric. Three types of AARM sub-fabric were distinguished. The AARM type 1 represents magnetic foliations parallel either to NNW–SSE or to NE–SW oriented joints with magnetic lineations distributed along the joins. In the AARM type 2 magnetic foliations remained parallel to the bedding while magnetic lineations group around the joint to bedding intersections. The AARM type 3 coincides with the AMS fabric. Magnetic and microscopic analyses indicate that the AARM fabrics are connected to magnetite associated with subordinate ferrimagnetic iron sulphides. Both minerals occur in a sub-microscopic size and formed most likely during late diagenesis through the alteration of pyrite, possibly accompanied by burial clay transformation processes. The growth of the authigenic ferrimagnetic minerals was conditioned by combined effects of the sedimentary petrofabric, lithology and stress conditions during the inversion of the basin in the Early to Middle Miocene.
{"title":"Magnetic fabrics in the turbidite deposits of the Central Carpathian Paleogene Basin in relation to sedimentary and tectonic fabric elements","authors":"Jozef Madzin, E. Márton, D. Starek, T. Mikuš","doi":"10.31577/geolcarp.72.2.4","DOIUrl":"https://doi.org/10.31577/geolcarp.72.2.4","url":null,"abstract":"Anisotropy of magnetic susceptibility and anisotropy of anhysteretic remanent magnetization were studied in the Oligocene turbidites of the weakly deformed Central Carpathian Paleogene Basin. In order to decide whether the magnetic fabric can be related to deposition from a paleoflow or to incipient weak tectonic deformation we compared magnetic fabrics in individual intervals of the Bouma sequence with sedimentary structures and tectonic brittle mesostructures (joints). In the Ta–Te intervals we observed a good correlation between maximum susceptibility axes and SW(W)–NE(E) oriented paleoflows. Within convoluted and slump folded sandstones the AMS fabric coincides with the orientation of soft-sediment deformation structures. These features suggest the sedimentary origin of the AMS fabric. Three types of AARM sub-fabric were distinguished. The AARM type 1 represents magnetic foliations parallel either to NNW–SSE or to NE–SW oriented joints with magnetic lineations distributed along the joins. In the AARM type 2 magnetic foliations remained parallel to the bedding while magnetic lineations group around the joint to bedding intersections. The AARM type 3 coincides with the AMS fabric. Magnetic and microscopic analyses indicate that the AARM fabrics are connected to magnetite associated with subordinate ferrimagnetic iron sulphides. Both minerals occur in a sub-microscopic size and formed most likely during late diagenesis through the alteration of pyrite, possibly accompanied by burial clay transformation processes. The growth of the authigenic ferrimagnetic minerals was conditioned by combined effects of the sedimentary petrofabric, lithology and stress conditions during the inversion of the basin in the Early to Middle Miocene.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70013014","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 : 2021-01-01DOI: 10.31577/geolcarp.72.2.5
D. Matýsek, J. Jirásek
This research focuses on two new occurrences of sedimentary concretions in the Subsilesian Unit of the Outer Western Carpathians (Czech Republic) from non-calcareous clays and claystones of the Paleocene to the Eocene age. Powder X-ray diffraction study proved heterogenous matrix, varying in content of siderite, Mn-rich siderite, Ca-rich rhodochrosite and fluorapatite. Electron microscopy revealed microsparitic carbonates with indistinct zoning. According to the geochemical and stable isotope clues the concretions originated in medium to highly reducting environment during early diagenesis. Stable isotope δ13C values (−11.3 and −4.8 ‰ PDB) and δ18O (1.8 and 1.0 ‰ PDB) correspond well to early diagenetic marine carbonates and part of the CO2 was derived from oxidation of biological material. Weathering of concretions has been on the surface and along fissures. While siderite-rich concretions produce goethite, rhodochrositerich concretions produce a cellular structure of todorokite, birnessite and buserite on rims of carbonate cores. Fissure mineralisation contains association of goethite accompanied by native selenium and clausthalite. The origin of the selenium minerals is interpreted as products on the redox barrier between Mn2+/Mn4+ and/or Fe2+/Fe3+, where selenites and selenates are highly soluble but native selenium and selenides are extremely insoluble.
{"title":"Manganese-rich carbonate and phosphate concretions from the Subsilesian Unit of the Outer Western Carpathians (Czech Republic): Composition and unique selenium weathering products","authors":"D. Matýsek, J. Jirásek","doi":"10.31577/geolcarp.72.2.5","DOIUrl":"https://doi.org/10.31577/geolcarp.72.2.5","url":null,"abstract":"This research focuses on two new occurrences of sedimentary concretions in the Subsilesian Unit of the Outer Western Carpathians (Czech Republic) from non-calcareous clays and claystones of the Paleocene to the Eocene age. Powder X-ray diffraction study proved heterogenous matrix, varying in content of siderite, Mn-rich siderite, Ca-rich rhodochrosite and fluorapatite. Electron microscopy revealed microsparitic carbonates with indistinct zoning. According to the geochemical and stable isotope clues the concretions originated in medium to highly reducting environment during early diagenesis. Stable isotope δ13C values (−11.3 and −4.8 ‰ PDB) and δ18O (1.8 and 1.0 ‰ PDB) correspond well to early diagenetic marine carbonates and part of the CO2 was derived from oxidation of biological material. Weathering of concretions has been on the surface and along fissures. While siderite-rich concretions produce goethite, rhodochrositerich concretions produce a cellular structure of todorokite, birnessite and buserite on rims of carbonate cores. Fissure mineralisation contains association of goethite accompanied by native selenium and clausthalite. The origin of the selenium minerals is interpreted as products on the redox barrier between Mn2+/Mn4+ and/or Fe2+/Fe3+, where selenites and selenates are highly soluble but native selenium and selenides are extremely insoluble.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70013083","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 : 2020-10-26DOI: 10.31577/geolcarp.71.5.4
Emilia Tulan, Reinhard F. Sachsenhofer, G. Tari, Jakub Witkowski, D. M. Tămaș, A. Horvat, A. Tămaș
Diatomites are prolific hydrocarbon source rocks in many basins worldwide. In the broader Carpathians, diagenetically altered diatomites are called menilites, and menilitic shale successions are regarded as the most prolific hydrocarbon source rocks in the region. The abandoned Sibiciu de Sus quarry, located in the Eastern Carpathian Bend Zone of Romania, provides large exposures of the upper part of the Lower Miocene Upper Menilites, composed of various diatomite lithologies, cherts, menilitic shales and quartz-rich sandstone. The sediments are highly deformed due to soft-sediment deformation and subsequent Miocene to Pliocene contractional tectonics. Twenty-two diatom-bearing samples were examined in order (a) to determine the hydrocarbon source rock potential, (b) to document the diatom assemblages and (c) to interpret the depositional environment. The hydrocarbon potential of the studied rocks is considered good to very good, with an average TOC of 3.77 wt. % (max. 9.57 wt. % TOC) and type II–III kerogen (avg. HI: 384 mg HC/g TOC). Tmax does not exceed 424 °C suggesting that the organic matter is thermally immature. Despite that, the Production Index is high (0.1–0.3), which proves the presence of migrated hydrocarbons. The source potential index (SPI) indicates that the exposed section, if mature, could generate about 1.3 t HC/m2. As the diatom preservation does not enable chemical extraction of individual valves, this study describes only genus-level findings. The diatom assemblages are dominated by Aulacoseira and Actinocyclus, whereas Ellerbeckia, Paralia and Rhaphoneis are rarely observed. The diatom assemblages indicate a nearshore, brackish-water depositional setting.
硅藻土是世界上许多盆地中丰富的烃源岩。在更广阔的喀尔巴阡山脉，成岩蚀变硅藻土被称为细粒岩，细粒岩页岩序列被认为是该地区最丰富的烃源岩。废弃的Sibiciu de Sus采石场位于罗马尼亚的东喀尔巴阡弯曲带，提供了下中新世上蒙利岩上部的大量暴露物，由各种硅藻土岩性、燧石、蒙利岩页岩和富含石英的砂岩组成。由于软沉积变形和随后中新世至上新世的收缩构造，沉积物高度变形。为了(a)确定烃源岩潜力，(b)记录硅藻组合，(c)解释沉积环境，对22个含硅藻样品进行了检查。所研究岩石的烃潜力被认为是好到非常好，平均TOC为3.77 wt. %(最大)。9.57 wt. % TOC)和II-III型干酪根(平均HI: 384 mg HC/g TOC)。Tmax不超过424℃，表明有机质热不成熟。尽管如此，生产指数仍然很高(0.1-0.3)，这证明了运移烃的存在。源电位指数(SPI)表明，暴露剖面成熟后可产生约1.3 t HC/m2。由于硅藻保存不允许化学提取单个阀门，本研究仅描述属水平的发现。硅藻组合以Aulacoseira和放线菌属(Actinocyclus)为主，Ellerbeckia、Paralia和Rhaphoneis较为少见。硅藻组合表明近岸微咸水沉积环境。
{"title":"Hydrocarbon source rock potential and paleoenvironment of lower Miocene diatomites in the Eastern Carpathians Bend Zone (Sibiciu de Sus, Romania)","authors":"Emilia Tulan, Reinhard F. Sachsenhofer, G. Tari, Jakub Witkowski, D. M. Tămaș, A. Horvat, A. Tămaș","doi":"10.31577/geolcarp.71.5.4","DOIUrl":"https://doi.org/10.31577/geolcarp.71.5.4","url":null,"abstract":"Diatomites are prolific hydrocarbon source rocks in many basins worldwide. In the broader Carpathians, diagenetically altered diatomites are called menilites, and menilitic shale successions are regarded as the most prolific hydrocarbon source rocks in the region. The abandoned Sibiciu de Sus quarry, located in the Eastern Carpathian Bend Zone of Romania, provides large exposures of the upper part of the Lower Miocene Upper Menilites, composed of various diatomite lithologies, cherts, menilitic shales and quartz-rich sandstone. The sediments are highly deformed due to soft-sediment deformation and subsequent Miocene to Pliocene contractional tectonics. Twenty-two diatom-bearing samples were examined in order (a) to determine the hydrocarbon source rock potential, (b) to document the diatom assemblages and (c) to interpret the depositional environment. The hydrocarbon potential of the studied rocks is considered good to very good, with an average TOC of 3.77 wt. % (max. 9.57 wt. % TOC) and type II–III kerogen (avg. HI: 384 mg HC/g TOC). Tmax does not exceed 424 °C suggesting that the organic matter is thermally immature. Despite that, the Production Index is high (0.1–0.3), which proves the presence of migrated hydrocarbons. The source potential index (SPI) indicates that the exposed section, if mature, could generate about 1.3 t HC/m2. As the diatom preservation does not enable chemical extraction of individual valves, this study describes only genus-level findings. The diatom assemblages are dominated by Aulacoseira and Actinocyclus, whereas Ellerbeckia, Paralia and Rhaphoneis are rarely observed. The diatom assemblages indicate a nearshore, brackish-water depositional setting.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46242891","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 : 2020-10-26DOI: 10.31577/geolcarp.71.5.3
L. Patkó, L. Creon, Z. Kovács, N. Liptai, E. Rosenberg, C. Szabó
In this study, three clinopyroxene-enriched upper mantle xenoliths, petrographically classified as wehrlite, were investigated from the Nógrád–Gömör Volcanic Field with the use of X-ray microtomography. Our main goal was to quantify the volume of the glass phase and the vesicles to reveal their three-dimensional distribution. Among the studied wehrlite xenoliths, one is weakly and two are strongly metasomatized. The two latter wehrlite xenoliths are characterized by higher modal amount of glass and vesicles, which suggests a genetic connection between glass and concomitant vesicles, and the metasomatic agent. The glass, which was a melt at mantle conditions, forms an interconnected network. This may explain the presence of the electromagnetic anomaly with high electrical conductivity beneath the study area. Our study contributes to the better understanding of melt migration and its metasomatic effect in the lithospheric mantle beneath monogenetic volcanic fields.
{"title":"Three-dimensional distribution of glass and vesicles in metasomatized xenoliths: A micro-CT case study from Nógrád–Gömör Volcanic Field (Northern Pannonian Basin)","authors":"L. Patkó, L. Creon, Z. Kovács, N. Liptai, E. Rosenberg, C. Szabó","doi":"10.31577/geolcarp.71.5.3","DOIUrl":"https://doi.org/10.31577/geolcarp.71.5.3","url":null,"abstract":"In this study, three clinopyroxene-enriched upper mantle xenoliths, petrographically classified as wehrlite, were investigated from the Nógrád–Gömör Volcanic Field with the use of X-ray microtomography. Our main goal was to quantify the volume of the glass phase and the vesicles to reveal their three-dimensional distribution. Among the studied wehrlite xenoliths, one is weakly and two are strongly metasomatized. The two latter wehrlite xenoliths are characterized by higher modal amount of glass and vesicles, which suggests a genetic connection between glass and concomitant vesicles, and the metasomatic agent. The glass, which was a melt at mantle conditions, forms an interconnected network. This may explain the presence of the electromagnetic anomaly with high electrical conductivity beneath the study area. Our study contributes to the better understanding of melt migration and its metasomatic effect in the lithospheric mantle beneath monogenetic volcanic fields.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49059539","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 : 2020-10-26DOI: 10.31577/geolcarp.71.5.5
I. Ilieş, Gelu Oltean, Raluca Bindiu Haitonic, S. Filipescu, Angela Miclea, C. Jipa
The paleoenvironmental changes produced during the early middle Miocene have been restored based on foraminiferal assemblages collected from the Hațeg Basin in the southwestern part of Transylvania. The identified planktonics suggest a late early Badenian age (Orbulina suturalis: mid-late Langhian) and relatively warm water temperature (high percentages of Trilobatus trilobus together with Trilobatus quadrilobatus, Globigerinella regularis, and Orbulina suturalis). Composition, abundance, diversity, and distribution of the benthic assemblages indicate fluctuations in the paleoecological parameters and nutrient supply in shelf settings. Separating the assemblages based on the preferred life habitat and feeding strategies along with analysis of species distribution using univariate (Fisher Alpha, Shannon, Simpson, Pielou, Hurlbert) and multivariate statistical indices (Bray Curtis distance matrix) aided in interpreting the paleoenvironmental changes along the succession (food content, oxygenation, changes in the hydrodynamics). The results suggest a relatively shallow and well-oxygenated depositional environment with few intervals of increased nutrient supply and decreased oxygen content, warm surface waters as well as a deepening upward trend along the section.
{"title":"Early middle Miocene paleoenvironmental evolution in southwest Transylvania (Romania): Interpretation based on foraminifera","authors":"I. Ilieş, Gelu Oltean, Raluca Bindiu Haitonic, S. Filipescu, Angela Miclea, C. Jipa","doi":"10.31577/geolcarp.71.5.5","DOIUrl":"https://doi.org/10.31577/geolcarp.71.5.5","url":null,"abstract":"The paleoenvironmental changes produced during the early middle Miocene have been restored based on foraminiferal assemblages collected from the Hațeg Basin in the southwestern part of Transylvania. The identified planktonics suggest a late early Badenian age (Orbulina suturalis: mid-late Langhian) and relatively warm water temperature (high percentages of Trilobatus trilobus together with Trilobatus quadrilobatus, Globigerinella regularis, and Orbulina suturalis). Composition, abundance, diversity, and distribution of the benthic assemblages indicate fluctuations in the paleoecological parameters and nutrient supply in shelf settings. Separating the assemblages based on the preferred life habitat and feeding strategies along with analysis of species distribution using univariate (Fisher Alpha, Shannon, Simpson, Pielou, Hurlbert) and multivariate statistical indices (Bray Curtis distance matrix) aided in interpreting the paleoenvironmental changes along the succession (food content, oxygenation, changes in the hydrodynamics). The results suggest a relatively shallow and well-oxygenated depositional environment with few intervals of increased nutrient supply and decreased oxygen content, warm surface waters as well as a deepening upward trend along the section.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49283443","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 : 2020-10-26DOI: 10.31577/geolcarp.71.5.1
I. Broska, M. Svojtka
In situ U–Pb zircon dating by the ICP-MS technique from tonalite located in the southern margin of the Kriváňska Malá Fatra granite massif records a Concordant age of 353 ± 3 Ma for zircon cores, 342 ± 3 Ma for their rims but the zircons from granodiorite on the northern margin of the massif show only coeval Concordant age of 342 ± 3 Ma from both cores and rims. The obtained ages establish successive Tournaisian and Visean magmatic events in the Variscan Malá Fatra crystalline basement and an intimate relationships between two Early Carboniferous intrusions. The Th/U ratio from zircon cores of Tournaisian tonalite shows a magmatic value of 1.0, whereas the ratio with value of 0.2 from zircon rims most likely represent the thermal imprint from emanated hydrothermal fluids from identified Visean granodiorite intrusion with similar Th/U zircon ratio of 0.4. The short time span of about 11 Ma for the origin of these two granitoid intrusive phases in the Malá Fatra Mountains advocates a relatively rapid Variscan convergence from a probably terminated Tournaisian arc magmatic regime to Visean collisional setting.
利用ICP-MS技术对位于Kriváňska mal Fatra花岗岩地块南缘的闪长岩进行原位U-Pb定年，锆石岩心和边缘的年龄分别为353±3 Ma和342±3 Ma，而地块北缘花岗闪长岩的锆石的年龄均为342±3 Ma。所获得的年龄确定了Variscan malfatra结晶基底连续的Tournaisian和Visean岩浆事件，以及两个早石炭世侵入之间的密切关系。图尔纳色闪长岩锆石岩心Th/U比值为1.0，锆石岩心Th/U比值为0.2，表明锆石岩心Th/U比值为0.4的锆石锆石岩心Th/U比值极有可能代表了已识别的维桑花岗闪长岩侵入岩岩浆热液的热印记。马尔法特拉山脉这两个花岗质侵入相的形成时间跨度约为11 Ma，表明从可能终止的图尔纳弧岩浆体系到维西碰撞体系的Variscan辐合过程相对较快。
{"title":"Early Carboniferous successive I/S granite magmatism recorded in the Malá Fatra Mountains by LA-ICP-MS zircon dating (Western Carpathians)","authors":"I. Broska, M. Svojtka","doi":"10.31577/geolcarp.71.5.1","DOIUrl":"https://doi.org/10.31577/geolcarp.71.5.1","url":null,"abstract":"In situ U–Pb zircon dating by the ICP-MS technique from tonalite located in the southern margin of the Kriváňska Malá Fatra granite massif records a Concordant age of 353 ± 3 Ma for zircon cores, 342 ± 3 Ma for their rims but the zircons from granodiorite on the northern margin of the massif show only coeval Concordant age of 342 ± 3 Ma from both cores and rims. The obtained ages establish successive Tournaisian and Visean magmatic events in the Variscan Malá Fatra crystalline basement and an intimate relationships between two Early Carboniferous intrusions. The Th/U ratio from zircon cores of Tournaisian tonalite shows a magmatic value of 1.0, whereas the ratio with value of 0.2 from zircon rims most likely represent the thermal imprint from emanated hydrothermal fluids from identified Visean granodiorite intrusion with similar Th/U zircon ratio of 0.4. The short time span of about 11 Ma for the origin of these two granitoid intrusive phases in the Malá Fatra Mountains advocates a relatively rapid Variscan convergence from a probably terminated Tournaisian arc magmatic regime to Visean collisional setting.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46320101","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 : 2020-10-26DOI: 10.31577/geolcarp.71.5.6
L. Krmíček, J. Ulrych, Petra Šišková, Simona Krmíčková, P. Spacek, Š. Křížová
Representative samples covering all petrographic types of the Miocene subvolcanic (dykes and sills) basalt– trachyte rock association from the Uherský Brod area (UB, Moravia) in the Czech Republic were studied. The UB area is associated with the Klippen Zone in the neighbourhood of the contact of the Carpathian–Pannonian Block with the Bohemian Massif. The petrographic and geochemical features of the subvolcanic rocks from the UB area only partly resemble those of the calc-alkaline rocks in a similar structural position in the coeval Pieniny area in Poland as well as of the transitional calc-alkaline rocks from the Central Slovakian volcanic field. The Miocene subvolcanic rocks were generated by melting of the variably metasomatised sub-lithospheric source and subsequent fractional crystallisation of the primary basaltic magma. The compositional characteristics of this rock series straddle the alkaline and subalkaline volcanic rock fields, while the rocks from the Pieniny area and from the Central Slovakian volcanic field are predominantly calc-alkaline andesites. The distribution of incompatible elements such as U, Th, REE, Nb, Ta, Sr, Ba as well as LaN/YbN ratios and Sr–Nd–Pb isotope composition of the rocks from the UB and Pieniny areas differ substantially, whereas the geochemical patterns of the UB rocks are slightly similar to those of the transitional rocks from the Central Slovakian volcanic field. The modest contents of incompatible trace elements in the andesitic rocks from the Pieniny area share several characteristics of the prevalent calc-alkaline andesitic rocks from the Carpathian–Pannonian region. Basaltic–trachytic series from the UB area are characterised by higher ɛNd (~2.5) and lower 87Sr/86Sr (~0.704) and 207Pb/204Pb (~15.65) initial values in comparison with the calc-alkaline rocks from the Carpathian–Pannonian region including the Pieniny area. Nevertheless, the basaltic–trachytic rocks from the UB, richer in some of the incompatible trace elements (e.g., U, Th, REE, Sr and Ba) partly resemble (including Sr–Nd–Pb isotopes) the Na-alkaline Miocene volcanic rock series of the NE shoulder of the Cheb–Domažlice Graben in the Bohemian Massif.
{"title":"Geochemistry and Sr–Nd–Pb isotope characteristics of Miocene basalt–trachyte rock association in transitional zone between the Outer Western Carpathians and Bohemian Massif","authors":"L. Krmíček, J. Ulrych, Petra Šišková, Simona Krmíčková, P. Spacek, Š. Křížová","doi":"10.31577/geolcarp.71.5.6","DOIUrl":"https://doi.org/10.31577/geolcarp.71.5.6","url":null,"abstract":"Representative samples covering all petrographic types of the Miocene subvolcanic (dykes and sills) basalt– trachyte rock association from the Uherský Brod area (UB, Moravia) in the Czech Republic were studied. The UB area is associated with the Klippen Zone in the neighbourhood of the contact of the Carpathian–Pannonian Block with the Bohemian Massif. The petrographic and geochemical features of the subvolcanic rocks from the UB area only partly resemble those of the calc-alkaline rocks in a similar structural position in the coeval Pieniny area in Poland as well as of the transitional calc-alkaline rocks from the Central Slovakian volcanic field. The Miocene subvolcanic rocks were generated by melting of the variably metasomatised sub-lithospheric source and subsequent fractional crystallisation of the primary basaltic magma. The compositional characteristics of this rock series straddle the alkaline and subalkaline volcanic rock fields, while the rocks from the Pieniny area and from the Central Slovakian volcanic field are predominantly calc-alkaline andesites. The distribution of incompatible elements such as U, Th, REE, Nb, Ta, Sr, Ba as well as LaN/YbN ratios and Sr–Nd–Pb isotope composition of the rocks from the UB and Pieniny areas differ substantially, whereas the geochemical patterns of the UB rocks are slightly similar to those of the transitional rocks from the Central Slovakian volcanic field. The modest contents of incompatible trace elements in the andesitic rocks from the Pieniny area share several characteristics of the prevalent calc-alkaline andesitic rocks from the Carpathian–Pannonian region. Basaltic–trachytic series from the UB area are characterised by higher ɛNd (~2.5) and lower 87Sr/86Sr (~0.704) and 207Pb/204Pb (~15.65) initial values in comparison with the calc-alkaline rocks from the Carpathian–Pannonian region including the Pieniny area. Nevertheless, the basaltic–trachytic rocks from the UB, richer in some of the incompatible trace elements (e.g., U, Th, REE, Sr and Ba) partly resemble (including Sr–Nd–Pb isotopes) the Na-alkaline Miocene volcanic rock series of the NE shoulder of the Cheb–Domažlice Graben in the Bohemian Massif.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45335115","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 : 2020-10-26DOI: 10.31577/geolcarp.71.5.2
P. Jirman, E. Geršlová, M. Bubík, Reinhard F. Sachsenhofer, L. Medvecká
The Oligocene Menilite Formation represents the most important hydrocarbon source rock in the Flysch Carpathians. The formation is laterally uniform across long distances but shows strong vertical heterogeneity reflecting changes in depositional environments, which control the source rock potential. In the Czech Republic, the Menilite Formation is subdivided into the Subchert Member (nannofossil zone NP22), Chert Member (upper NP22 to lower NP23), Dynów Marlstone (NP23) and Šitbořice Member (upper NP23 to lower NP25). The present study describes in detail the Bystřice nad Olší section in the Subsilesian Unit where all four members are exposed including the uppermost part of the underlying Frýdlant Formation (Sheshory Marls). The present Frýdlant Formation has a negligible source rock potential compared to the Menilite Formation. The Menilite Formation in the Bystřice nad Olší section has mostly “good” source rock potential, although the TOC indicates “very good” potential. The Subchert Member (average TOC: 3.6 wt. %; HI up to 505 mg HC/g TOC) and the Chert Member (average TOC: 2.2 wt. %; HI up to 790 mg HC/g TOC) are the most prolific units. Based on organic petrography and HI, the kerogen is classified as type II and I. Indications of admixtures of type III kerogen are limited to samples with low TOC contents (<1 wt. %). The Source Potential Index (SPI) of the Menilite Formation in the Subsilesian Unit of the Czech Republic is estimated as ~1.15 t HC/m2 which is comparable to SPI calculated for sections in the Silesian and Ždánice units in the Czech Republic and for the Waschberg Zone in Austria. Significantly higher SPI values estimated for the Polish and especially the Ukrainian Carpathians (up to 74.5 t HC/m2) are caused by a wider stratigraphic range, several times greater thickness and higher total organic matter content.
渐新统Menilite组是弗理石喀尔巴阡山脉最重要的烃源岩。地层横向上长距离均匀，但纵向上非均质性强，反映了沉积环境的变化，控制了烃源岩潜力。在捷克，Menilite组被划分为小燧石段(纳米化石带NP22)、燧石段(NP22上至NP23下)、Dynów泥灰岩段(NP23上至NP25下)和Šitbořice段(NP23上至NP25下)。本研究详细描述了Subsilesian单元的Bystřice nad Olší段，其中所有四个成员都暴露在其中，包括下伏Frýdlant组(Sheshory Marls)的最上部。与Menilite组相比，目前的Frýdlant组的烃源岩潜力可以忽略不计。Bystřice nad Olší段Menilite组烃源岩潜力为“好”，TOC值为“非常好”。分契成员(平均TOC: 3.6 wt. %;HI高达505 mg HC/g TOC)和cht成员(平均TOC: 2.2 wt. %;HI高达790 mg HC/g TOC)是最多产的单位。根据有机岩相学和HI，将干酪根分为II型和i型。III型干酪根混合物的迹象仅限于TOC含量较低(<1 wt. %)的样品。捷克共和国Subsilesian单元Menilite组的源电位指数(SPI)估计为~1.15 t HC/m2，与捷克共和国Silesian和Ždánice单元的剖面以及奥地利Waschberg带的SPI相当。波兰，特别是乌克兰喀尔巴阡山脉的SPI值(高达74.5 t HC/m2)明显较高，这是由于地层范围更宽，厚度大几倍，总有机质含量更高。
{"title":"Source rock potential of the Oligocene Menilite Formation in the Czech sector of the Subsilesian Unit (Flysch Carpathians)","authors":"P. Jirman, E. Geršlová, M. Bubík, Reinhard F. Sachsenhofer, L. Medvecká","doi":"10.31577/geolcarp.71.5.2","DOIUrl":"https://doi.org/10.31577/geolcarp.71.5.2","url":null,"abstract":"The Oligocene Menilite Formation represents the most important hydrocarbon source rock in the Flysch Carpathians. The formation is laterally uniform across long distances but shows strong vertical heterogeneity reflecting changes in depositional environments, which control the source rock potential. In the Czech Republic, the Menilite Formation is subdivided into the Subchert Member (nannofossil zone NP22), Chert Member (upper NP22 to lower NP23), Dynów Marlstone (NP23) and Šitbořice Member (upper NP23 to lower NP25). The present study describes in detail the Bystřice nad Olší section in the Subsilesian Unit where all four members are exposed including the uppermost part of the underlying Frýdlant Formation (Sheshory Marls). The present Frýdlant Formation has a negligible source rock potential compared to the Menilite Formation. The Menilite Formation in the Bystřice nad Olší section has mostly “good” source rock potential, although the TOC indicates “very good” potential. The Subchert Member (average TOC: 3.6 wt. %; HI up to 505 mg HC/g TOC) and the Chert Member (average TOC: 2.2 wt. %; HI up to 790 mg HC/g TOC) are the most prolific units. Based on organic petrography and HI, the kerogen is classified as type II and I. Indications of admixtures of type III kerogen are limited to samples with low TOC contents (<1 wt. %). The Source Potential Index (SPI) of the Menilite Formation in the Subsilesian Unit of the Czech Republic is estimated as ~1.15 t HC/m2 which is comparable to SPI calculated for sections in the Silesian and Ždánice units in the Czech Republic and for the Waschberg Zone in Austria. Significantly higher SPI values estimated for the Polish and especially the Ukrainian Carpathians (up to 74.5 t HC/m2) are caused by a wider stratigraphic range, several times greater thickness and higher total organic matter content.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44686444","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 : 2020-08-01DOI: 10.31577/geolcarp.71.4.1
Petronela Nováková, S. Rybár, Katarína Šarinová, A. Nagy, N. Hudáčková, Michal Jamrich, V. Teodoridis, M. Kováčová, Michal Šujan, T. Vlček, M. Kováč
The late Badenian and Sarmatian (Serravallian) evolution of depositional environments in the Danube Basin (Želiezovce Depression) has never been fully explored. Here, we clarify the paleoenvironmental changes which took place in this area during the late Badenian and Sarmatian on the basis of sedimentological, petrographic, biostratigraphic and paleobotanical analyses performed at multiple sections. The combination of these methods with sequence stratigraphy allowed us to divide the sedimentary record into three main intervals: 1) the transgressive late Badenian rocky shore deposits (transgressive and/or highstand system tract), followed by a gap in the stratigraphic record (that can approximately coincide with the latest Badenian falling stage system tract). 2) Earliest Sarmatian terrestrial deposits connected with the beginning of the Sarmatian transgression (synchronous with the lowstand system tract). 3) The early Sarmatian deltaic environment influenced by tidal processes associated with the highstand system tract. The fossil leaf association indicates a climatic turnover from subtropical to temperate conditions between the earliest (lowstand system tract) and the early Sarmatian (highstand system tract). Sediments of the late Sarmatian (falling stage system tract) were not deposited or were later eroded. However, they may be present in the neighbouring depressions, which tectonically opened during the late Sarmatian. The Badenian–Sarmatian boundary in the Želiezovce Depression is developed in transgressive shallow marine to terrestrial volcano-sediments as is typical for this boundary in most other Paratethys depocentres.
{"title":"The late Badenian–Sarmatian (Serravallian) environmental transition calibrated by sequence stratigraphy (eastern Danube Basin, Central Paratethys)","authors":"Petronela Nováková, S. Rybár, Katarína Šarinová, A. Nagy, N. Hudáčková, Michal Jamrich, V. Teodoridis, M. Kováčová, Michal Šujan, T. Vlček, M. Kováč","doi":"10.31577/geolcarp.71.4.1","DOIUrl":"https://doi.org/10.31577/geolcarp.71.4.1","url":null,"abstract":"The late Badenian and Sarmatian (Serravallian) evolution of depositional environments in the Danube Basin (Želiezovce Depression) has never been fully explored. Here, we clarify the paleoenvironmental changes which took place in this area during the late Badenian and Sarmatian on the basis of sedimentological, petrographic, biostratigraphic and paleobotanical analyses performed at multiple sections. The combination of these methods with sequence stratigraphy allowed us to divide the sedimentary record into three main intervals: 1) the transgressive late Badenian rocky shore deposits (transgressive and/or highstand system tract), followed by a gap in the stratigraphic record (that can approximately coincide with the latest Badenian falling stage system tract). 2) Earliest Sarmatian terrestrial deposits connected with the beginning of the Sarmatian transgression (synchronous with the lowstand system tract). 3) The early Sarmatian deltaic environment influenced by tidal processes associated with the highstand system tract. The fossil leaf association indicates a climatic turnover from subtropical to temperate conditions between the earliest (lowstand system tract) and the early Sarmatian (highstand system tract). Sediments of the late Sarmatian (falling stage system tract) were not deposited or were later eroded. However, they may be present in the neighbouring depressions, which tectonically opened during the late Sarmatian. The Badenian–Sarmatian boundary in the Želiezovce Depression is developed in transgressive shallow marine to terrestrial volcano-sediments as is typical for this boundary in most other Paratethys depocentres.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43314334","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 : 2020-08-01DOI: 10.31577/geolcarp.71.4.2
Johannes F. RAUBALLL, Reinhard F. Sachsenhofer, A. Bechtel
Organic matter-rich rocks occur in the Carpathians, both in the Lower Cretaceous and Oligocene. Whereas, the Oligocene Menilite Formation has been intensely studied, the hydrocarbon potential of Lower Cretaceous rocks is less well understood. In the present paper a 405 m thick succession of the lower part of the Shypot Formation in the Chornohora nappe (Ukraine) is studied using 94 outcrop samples. Maturity parameters for the Lower Cretaceous rocks indicate peak oil maturity (~0.85 % Rr) and organic carbon content averages 2.8 wt. % for all samples. As a result of the enhanced maturity, the hydrogen index (88 mg HC/g TOC) and the remaining petroleum potential (2 tHC/m2) are low. Comparisons with coeval rocks from the same tectonic unit, but with lower maturity suggest that the original petroleum potential was significantly higher (4 tHC/m2). Probably about 2 tHC/m2 were generated during deep burial (6 km?), but were lost during uplift and erosion. Macerals analysis reveals a mixed type III-II kerogen, with domination of terrigenous components, which is also supported by HI values of nearby marginal mature samples (~200 mg HC/g TOC). Lower Cretaceous organic matter-rich rocks are found along the entire Carpathian arc. A compilation of published data for age-equivalent rocks across the Carpathian Fold-Thrust Belt shows that HI values are mainly controlled by maturity as well as the moderately high original HI values. Most of these rocks contain predominantly type III-II kerogen, whereas Lower Cretaceous rocks in the Skole-Skyba nappe near the Polish–Ukrainian border contain type (III-) IV kerogen.
{"title":"Hydrocarbon potential of the Lower Cretaceous (Barremian–Albian) Shypot Formation in the Chornohora nappe, Ukraine","authors":"Johannes F. RAUBALLL, Reinhard F. Sachsenhofer, A. Bechtel","doi":"10.31577/geolcarp.71.4.2","DOIUrl":"https://doi.org/10.31577/geolcarp.71.4.2","url":null,"abstract":"Organic matter-rich rocks occur in the Carpathians, both in the Lower Cretaceous and Oligocene. Whereas, the Oligocene Menilite Formation has been intensely studied, the hydrocarbon potential of Lower Cretaceous rocks is less well understood. In the present paper a 405 m thick succession of the lower part of the Shypot Formation in the Chornohora nappe (Ukraine) is studied using 94 outcrop samples. Maturity parameters for the Lower Cretaceous rocks indicate peak oil maturity (~0.85 % Rr) and organic carbon content averages 2.8 wt. % for all samples. As a result of the enhanced maturity, the hydrogen index (88 mg HC/g TOC) and the remaining petroleum potential (2 tHC/m2) are low. Comparisons with coeval rocks from the same tectonic unit, but with lower maturity suggest that the original petroleum potential was significantly higher (4 tHC/m2). Probably about 2 tHC/m2 were generated during deep burial (6 km?), but were lost during uplift and erosion. Macerals analysis reveals a mixed type III-II kerogen, with domination of terrigenous components, which is also supported by HI values of nearby marginal mature samples (~200 mg HC/g TOC). Lower Cretaceous organic matter-rich rocks are found along the entire Carpathian arc. A compilation of published data for age-equivalent rocks across the Carpathian Fold-Thrust Belt shows that HI values are mainly controlled by maturity as well as the moderately high original HI values. Most of these rocks contain predominantly type III-II kerogen, whereas Lower Cretaceous rocks in the Skole-Skyba nappe near the Polish–Ukrainian border contain type (III-) IV kerogen.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41267865","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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