Pub Date : 2023-06-27DOI: 10.31577/geolcarp.2023.01
Mădălina-Elena Kallanxhi
: The Albanian–Thessalian Basin, which is located in the vicinity of Mount Morava, includes Eocene to Middle Miocene sediments with a poorly-known, calcareous nannofossil content. This study is focused on the investigation of calcareous nannofossil assemblages from the Lower Miocene sediments outcropping in the area, resulting in the correlation to the global nannofossils zones/subzones NN2–NN3/CN1c–CN2, as well as to the zonation from the Mediterranean area, where the MNN2b and MNN3a biozones have been identified. An early-middle Burdigalian age for the studied outcrops is supported by primary and secondary index species ( Helicosphaera ampliaperta , Helicosphaera mediterranea , Sphenolithus belemnos , Sphenolithus disbelemnos , Sphenolithus pseudoheteromorphus ). Quantitative analyses were performed on calcareous nannofossils and statistics were applied to all of the counted samples. Based on the statistical analysis, short-time fluctuations in palaeoenvironmental parameters, such as temperature, salinity and eutrophic regime, are documented through the changes in the calcareous nannofossil assemblages and their abundance patterns. The depositional palaeoenvironment indicates changes in basin water depth, with influence of cold upwelling currents, terrigenous nutrient influx, and increased palaeoenvironmental perturbations over short time intervals
{"title":"Biostratigraphy of calcareous nannofossils and palaeoenvironments in the Lower Miocene of the Albanian–Thessalian Basin (Albania)","authors":"Mădălina-Elena Kallanxhi","doi":"10.31577/geolcarp.2023.01","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.01","url":null,"abstract":": The Albanian–Thessalian Basin, which is located in the vicinity of Mount Morava, includes Eocene to Middle Miocene sediments with a poorly-known, calcareous nannofossil content. This study is focused on the investigation of calcareous nannofossil assemblages from the Lower Miocene sediments outcropping in the area, resulting in the correlation to the global nannofossils zones/subzones NN2–NN3/CN1c–CN2, as well as to the zonation from the Mediterranean area, where the MNN2b and MNN3a biozones have been identified. An early-middle Burdigalian age for the studied outcrops is supported by primary and secondary index species ( Helicosphaera ampliaperta , Helicosphaera mediterranea , Sphenolithus belemnos , Sphenolithus disbelemnos , Sphenolithus pseudoheteromorphus ). Quantitative analyses were performed on calcareous nannofossils and statistics were applied to all of the counted samples. Based on the statistical analysis, short-time fluctuations in palaeoenvironmental parameters, such as temperature, salinity and eutrophic regime, are documented through the changes in the calcareous nannofossil assemblages and their abundance patterns. The depositional palaeoenvironment indicates changes in basin water depth, with influence of cold upwelling currents, terrigenous nutrient influx, and increased palaeoenvironmental perturbations over short time intervals","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70011938","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 : 2023-06-01DOI: 10.31577/geolcarp.2023.06
M. Matošević, Frane Marković, D. Bigunac, S. Šuica, K. Krizmanić, Adaleta Perković, M. Kovácic, D. Pavelić
: This paper presents a petrographic study of the Upper Miocene sandstones from exploration wells in the Sava and Drava Depressions in the North Croatian Basin (SW of the Pannonian Basin System), Central Europe. These sandstones represent the most important reservoir rocks for oil and gas in Croatia. A total of 130 core samples from depths of more than 3000 m were examined. The sandstones generally have a feldspatho–litho–quartzose (fLQ) composition. The modal composition of samples from the Sava Depression is Q 39.2–61.0 F 8.9–26.0 L 26.1–42.3 , and Q 40.6–63.5 F 6.6–23.3 L 20.9–42.3
本文对中欧北克罗埃西亚盆地(潘诺尼亚盆地系西南)萨瓦和德拉瓦坳陷探井的上中新世砂岩进行了岩石学研究。这些砂岩是克罗地亚最重要的油气储层。总共检查了130个岩心样本，这些样本来自3000米以上的深度。砂岩一般具有长石-岩-石英(fLQ)组成。萨瓦坳陷样品的模态组成为Q 39.2 ~ 61.0 F 8.9 ~ 26.0 L 26.1 ~ 42.3, Q 40.6 ~ 63.5 F 6.6 ~ 23.3 L 20.9 ~ 42.3
{"title":"Petrography of the Upper Miocene sandstones from the North Croatian Basin: Understanding the genesis of the largest reservoirs in the southwestern part of the Pannonian Basin System","authors":"M. Matošević, Frane Marković, D. Bigunac, S. Šuica, K. Krizmanić, Adaleta Perković, M. Kovácic, D. Pavelić","doi":"10.31577/geolcarp.2023.06","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.06","url":null,"abstract":": This paper presents a petrographic study of the Upper Miocene sandstones from exploration wells in the Sava and Drava Depressions in the North Croatian Basin (SW of the Pannonian Basin System), Central Europe. These sandstones represent the most important reservoir rocks for oil and gas in Croatia. A total of 130 core samples from depths of more than 3000 m were examined. The sandstones generally have a feldspatho–litho–quartzose (fLQ) composition. The modal composition of samples from the Sava Depression is Q 39.2–61.0 F 8.9–26.0 L 26.1–42.3 , and Q 40.6–63.5 F 6.6–23.3 L 20.9–42.3","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48705937","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 : 2023-06-01DOI: 10.31577/geolcarp.2023.07
L. Galović, K. Beerten, Nina Hećej, Hrvoje Posilović
: The Đurđevac Sands refer to an extensive sandy region south of the Drava River in northern Croatia, where it builds distinctive aeolian dunes. To date, their chronostratigraphical position has been based on stratigraphical inferences (superposition) without numerical and absolute age control. The recent discovery of a buried double paleosoil below and above aeolian dune sands in an abandoned sandpit (Draganci) have allowed the determination of the first absolute dates of the Đurđevac Sands. Field observations and laboratory analyses indicate that the degree of pedogenetic development of these paleosoils is very low. They appear to belong to the arenosol soil type, which is also the dominant recent soil type in the area. 14 C analysis of charcoal from the paleosoils indicated their development during the Bølling–Allerød interstadial, approximately between 14.7 ka and 12.9 ka, as opposed to previous claims that they would be exclusively Holocene in age. Therefore, this shows the need for a detailed investigation of the Đurđevac Sands. The sands and paleosoils likely witnessed a series of alternating phases of landscape stability and instability during the Late Glacial and Holocene. Such episodes are known to have occurred in other sandy regions of the Carpathian basin as well.
{"title":"Đurđevac Sands and the intraformational paleosoils (Podravina, N Croatia) are newly dated to Late Pleistocene/Holocene","authors":"L. Galović, K. Beerten, Nina Hećej, Hrvoje Posilović","doi":"10.31577/geolcarp.2023.07","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.07","url":null,"abstract":": The Đurđevac Sands refer to an extensive sandy region south of the Drava River in northern Croatia, where it builds distinctive aeolian dunes. To date, their chronostratigraphical position has been based on stratigraphical inferences (superposition) without numerical and absolute age control. The recent discovery of a buried double paleosoil below and above aeolian dune sands in an abandoned sandpit (Draganci) have allowed the determination of the first absolute dates of the Đurđevac Sands. Field observations and laboratory analyses indicate that the degree of pedogenetic development of these paleosoils is very low. They appear to belong to the arenosol soil type, which is also the dominant recent soil type in the area. 14 C analysis of charcoal from the paleosoils indicated their development during the Bølling–Allerød interstadial, approximately between 14.7 ka and 12.9 ka, as opposed to previous claims that they would be exclusively Holocene in age. Therefore, this shows the need for a detailed investigation of the Đurđevac Sands. The sands and paleosoils likely witnessed a series of alternating phases of landscape stability and instability during the Late Glacial and Holocene. Such episodes are known to have occurred in other sandy regions of the Carpathian basin as well.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49090641","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 : 2023-06-01DOI: 10.31577/geolcarp.2023.09
R. Farkašovský, S. Jacko, Zdenka Babicová, Alexander Dean Thiessen
: During the Alpine convergence of the Central Western Carpathians, a set of subparallel NW–SE shear zones formed in the eastern part of the Veporic Unit, near the tectonic contact with the Gemeric Unit. Deformation in low-grade metamorphic conditions was typical of the Alpine movements in the shear zones. Mylonitic rocks of the crystalline complex and their cover formations were studied on a macro and micro scale to characterise the evolution of deformation structures in the shear zones. The differential stress of dynamically-recrystallized quartz, which aggregates in mylonitic rocks, was determined using quartz paleopiezometry. Several types of foliation structures, but mainly penetrative subhorizontal stretching lineation in all observed mylonites, provide evidence of stretching and oriented ductile flow in a NW–SE direction. Shear sense indicators show the subhorizontal movement of the shear zone hanging walls to the SE. Dynamically-recrystallized quartz aggregates in the mylonitic rocks show different values of grain sizes and differential stresses, depending on the structure in which they occur. The lowest differential stresses were found in the quartz aggregates parallel to the S planes of the mylonites. Higher values are related to the C shear bands. The character of the structural setting indicates the formation of the shear zones in the orogen-parallel extension conditions.
{"title":"Assessment of the deformation in the subparallel shear zone set: A case study from the Veporic Unit, Western Carpathians","authors":"R. Farkašovský, S. Jacko, Zdenka Babicová, Alexander Dean Thiessen","doi":"10.31577/geolcarp.2023.09","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.09","url":null,"abstract":": During the Alpine convergence of the Central Western Carpathians, a set of subparallel NW–SE shear zones formed in the eastern part of the Veporic Unit, near the tectonic contact with the Gemeric Unit. Deformation in low-grade metamorphic conditions was typical of the Alpine movements in the shear zones. Mylonitic rocks of the crystalline complex and their cover formations were studied on a macro and micro scale to characterise the evolution of deformation structures in the shear zones. The differential stress of dynamically-recrystallized quartz, which aggregates in mylonitic rocks, was determined using quartz paleopiezometry. Several types of foliation structures, but mainly penetrative subhorizontal stretching lineation in all observed mylonites, provide evidence of stretching and oriented ductile flow in a NW–SE direction. Shear sense indicators show the subhorizontal movement of the shear zone hanging walls to the SE. Dynamically-recrystallized quartz aggregates in the mylonitic rocks show different values of grain sizes and differential stresses, depending on the structure in which they occur. The lowest differential stresses were found in the quartz aggregates parallel to the S planes of the mylonites. Higher values are related to the C shear bands. The character of the structural setting indicates the formation of the shear zones in the orogen-parallel extension conditions.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49434610","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 : 2023-06-01DOI: 10.31577/geolcarp.2023.08
V. Bezák, M. Bielik, František Marko, P. Zahorec, R. Pašteka, J. Vozár, J. Papčo
: This paper analyzes the latest complete Bouguer gravity anomaly map of Slovakia in relation to geological architecture. The observed gravity field consists of regional and local gravity anomalies, as well as marked horizontal gravity gradients. The most remarkable regional feature on this map is the large field with low-density masses in the northern part of Central Slovakia (the so-called Western Carpathian gravity low), which is divided into two gravity sub-lows: the Outer and Inner Western Carpathian gravity low. The source of the first sub-low is the sediments of the Outer Western Carpathian flysch units, and the second one is a crust with prevailing granites and orthogneisses. It is suggested that this field is only the torso of the original one, which stretched along the entire length of Slovakia from the SW to the NE. However, in the youngest stages of tectonic development, the negative gravity anomalous field in the territory of West and East Slovakia changed to a positive one due to the thinning of the lithosphere and crust by the influence of asthenolithic masses from the mantle. The higher density masses in Central Slovakia south of the Carpathian gravity low are not caused only by asthenolithic action. The different tectonic segment with a predominance of metamorphic complexes and a higher average density, in comparison to the low-density granitized complexes in the north, also contributes to its manifestation. The boundary between these two segments in Central Slovakia is a linear and sharp tectonic zone and coincides with the extensive Pohorelá shear zone. Several local anomalies also occur on the complete Bouguer anomaly map, and they were also subjected to geological analysis. These include local areas with a predominance of heavier crust, such as the core mountains in western Slovakia, subvolcanic intrusions, metabasic complexes, and the Cadomian basements. Prominent horizontal gravity gradients reflect the tectonic interfaces (faults, shear zones) that originated mainly during the youngest period of the Western Carpathian tectonic development and were also interpreted. The faults shown in the complete Bouguer anomaly map were active mainly during the transpressional and extensional stage of the Neo-Alpine tectonic development.
{"title":"Geological and tectonic interpretation of new Bouguer gravity anomaly map of Slovakia","authors":"V. Bezák, M. Bielik, František Marko, P. Zahorec, R. Pašteka, J. Vozár, J. Papčo","doi":"10.31577/geolcarp.2023.08","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.08","url":null,"abstract":": This paper analyzes the latest complete Bouguer gravity anomaly map of Slovakia in relation to geological architecture. The observed gravity field consists of regional and local gravity anomalies, as well as marked horizontal gravity gradients. The most remarkable regional feature on this map is the large field with low-density masses in the northern part of Central Slovakia (the so-called Western Carpathian gravity low), which is divided into two gravity sub-lows: the Outer and Inner Western Carpathian gravity low. The source of the first sub-low is the sediments of the Outer Western Carpathian flysch units, and the second one is a crust with prevailing granites and orthogneisses. It is suggested that this field is only the torso of the original one, which stretched along the entire length of Slovakia from the SW to the NE. However, in the youngest stages of tectonic development, the negative gravity anomalous field in the territory of West and East Slovakia changed to a positive one due to the thinning of the lithosphere and crust by the influence of asthenolithic masses from the mantle. The higher density masses in Central Slovakia south of the Carpathian gravity low are not caused only by asthenolithic action. The different tectonic segment with a predominance of metamorphic complexes and a higher average density, in comparison to the low-density granitized complexes in the north, also contributes to its manifestation. The boundary between these two segments in Central Slovakia is a linear and sharp tectonic zone and coincides with the extensive Pohorelá shear zone. Several local anomalies also occur on the complete Bouguer anomaly map, and they were also subjected to geological analysis. These include local areas with a predominance of heavier crust, such as the core mountains in western Slovakia, subvolcanic intrusions, metabasic complexes, and the Cadomian basements. Prominent horizontal gravity gradients reflect the tectonic interfaces (faults, shear zones) that originated mainly during the youngest period of the Western Carpathian tectonic development and were also interpreted. The faults shown in the complete Bouguer anomaly map were active mainly during the transpressional and extensional stage of the Neo-Alpine tectonic development.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47729205","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 : 2023-06-01DOI: 10.31577/geolcarp.2023.10
S. Kiefer, P. Ivan, Andreas B. Kaufmann, Marek Vďačný, J. Majzlan
: Hydrothermal processes are mainly responsible for the release and accumulation of metals and metalloids in rocks. In this work, we investigated the mineralogy and geochemistry of altered metaultramafic rocks (listvenites) that are spatially associated with Ni–Co ores near Dobšiná aiming to identify the sources of the elements in the hydrothermal Ni–Co-mineralization. Optical microscopy, electron microprobe analysis, and laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were used to correlate the mineralogy with the degree of rock alteration. The sulfides and silicates in the metaultramafic rocks host rare, tiny inclusions of cooperite (nominally PtS), sperrylite (PtAs 2 ), Pty–Pd–Ir–Te phase, and Pt–Au–Cr-alloy. The results show that the metaultramafic rocks were the source of Ni and Co and that platinum-group elements (PGE) were also leached and mobilized from the metaultramafic rocks. LA-ICP-MS scans show that the sulfarsenides in the metaultramafic rocks host submicrometer inclusions of PGE minerals but the hydrothermal Ni–Co sulfarsenides contain much less PGE’s. These observations document the limited mobility of the PGE’s. Changes in the sulfide mineralogy as a function of degree of alteration suggest that the fluids brought Fe and S, and probably a substantial amount of As whereas the metaultramafic rocks supplied Ni, Co, PGE, and perhaps also some As.
{"title":"\"Remobilization of Ni–Co–As and platinum-group elements by carbonate metasomatic alteration (listvenitization) of metaultramafic rocks from Dobšiná, Slovakia\"","authors":"S. Kiefer, P. Ivan, Andreas B. Kaufmann, Marek Vďačný, J. Majzlan","doi":"10.31577/geolcarp.2023.10","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.10","url":null,"abstract":": Hydrothermal processes are mainly responsible for the release and accumulation of metals and metalloids in rocks. In this work, we investigated the mineralogy and geochemistry of altered metaultramafic rocks (listvenites) that are spatially associated with Ni–Co ores near Dobšiná aiming to identify the sources of the elements in the hydrothermal Ni–Co-mineralization. Optical microscopy, electron microprobe analysis, and laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were used to correlate the mineralogy with the degree of rock alteration. The sulfides and silicates in the metaultramafic rocks host rare, tiny inclusions of cooperite (nominally PtS), sperrylite (PtAs 2 ), Pty–Pd–Ir–Te phase, and Pt–Au–Cr-alloy. The results show that the metaultramafic rocks were the source of Ni and Co and that platinum-group elements (PGE) were also leached and mobilized from the metaultramafic rocks. LA-ICP-MS scans show that the sulfarsenides in the metaultramafic rocks host submicrometer inclusions of PGE minerals but the hydrothermal Ni–Co sulfarsenides contain much less PGE’s. These observations document the limited mobility of the PGE’s. Changes in the sulfide mineralogy as a function of degree of alteration suggest that the fluids brought Fe and S, and probably a substantial amount of As whereas the metaultramafic rocks supplied Ni, Co, PGE, and perhaps also some As.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47718831","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 : 2023-01-01DOI: 10.31577/geolcarp.2023.03
H. Öztürk, İ. Yılmaz, N. Aysal, Davut Laçin, Zeynep Cansu
: The İstanbul Pliocene deposits consist of an alternation of sand, clay, and coal in the northern part of İstanbul that characterizes a delta plain deposit on the southern coastal line of the Black Sea. The Pliocene sediments, which are located conformably on the fluvial sediments consisting of coarse clastics, are about 80 meters thick and outcrop as isolated patches in Şile in the east of the İstanbul Strait (Bosphorus) and Kısırkaya in the west. The U/Pb detrital zircon ages obtained from the sands of Kısırkaya and Şile region showed that the Pliocene deposits contain Proterozoic (2396 ± 72 – 542.4 ± 7.9 Ma), Paleozoic (540 ± 12 – 258.9 ± 5.2 Ma), Mesozoic (248.8 ± 4.4 – 71.8 ± 1.2 Ma), and Cenozoic (63 ± 1.8 – 22.18 ± 0.95 Ma) zircons derived from a piedmont plateau. Presence of the youngest Oligocene–early Miocene zircons (22.18 ± 0.95 – 31.1 ± 1.2 Ma) reveals that the source of this succession may be the Northwest Anatolia and/or northern Aegean region where magmatic rocks of the same age crop out. In addition to the zircon data in the sandy deposits, trace element geochemistry also shows that the drainage basin of the Pliocene rivers transporting clastics to the basin is located in the southwestern region of İstanbul and flowed into the Black Sea before the formation of the Marmara Sea. These rivers would have been blocked in the early Quaternary by the Marmara Sea depression, which was formed by extensional faults, the product of an approximately N–S extensional tectonic regime in the region. This tectonic regime caused the rapid uplifting of the İstanbul region and the Istranca Mountains in the north of the Marmara, and the eroded flattened areas called the Bursa–Balıkesir plateau in the south, in the form of horsts. Subsequently, before the North Anatolian fault reached the region, it formed deformation structures under the effect of dextral shear in a wide zone in the Marmara region. This tectonic regime was ended when the North Anatolian fault reached and cut the Marmara Sea region in the Latest Quaternary.
{"title":"Detrital zircon geochronology of Pliocene deltaic sediments in the Marmara region (Turkey): Implication for sedimentary provenance and morphotectonic evolution","authors":"H. Öztürk, İ. Yılmaz, N. Aysal, Davut Laçin, Zeynep Cansu","doi":"10.31577/geolcarp.2023.03","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.03","url":null,"abstract":": The İstanbul Pliocene deposits consist of an alternation of sand, clay, and coal in the northern part of İstanbul that characterizes a delta plain deposit on the southern coastal line of the Black Sea. The Pliocene sediments, which are located conformably on the fluvial sediments consisting of coarse clastics, are about 80 meters thick and outcrop as isolated patches in Şile in the east of the İstanbul Strait (Bosphorus) and Kısırkaya in the west. The U/Pb detrital zircon ages obtained from the sands of Kısırkaya and Şile region showed that the Pliocene deposits contain Proterozoic (2396 ± 72 – 542.4 ± 7.9 Ma), Paleozoic (540 ± 12 – 258.9 ± 5.2 Ma), Mesozoic (248.8 ± 4.4 – 71.8 ± 1.2 Ma), and Cenozoic (63 ± 1.8 – 22.18 ± 0.95 Ma) zircons derived from a piedmont plateau. Presence of the youngest Oligocene–early Miocene zircons (22.18 ± 0.95 – 31.1 ± 1.2 Ma) reveals that the source of this succession may be the Northwest Anatolia and/or northern Aegean region where magmatic rocks of the same age crop out. In addition to the zircon data in the sandy deposits, trace element geochemistry also shows that the drainage basin of the Pliocene rivers transporting clastics to the basin is located in the southwestern region of İstanbul and flowed into the Black Sea before the formation of the Marmara Sea. These rivers would have been blocked in the early Quaternary by the Marmara Sea depression, which was formed by extensional faults, the product of an approximately N–S extensional tectonic regime in the region. This tectonic regime caused the rapid uplifting of the İstanbul region and the Istranca Mountains in the north of the Marmara, and the eroded flattened areas called the Bursa–Balıkesir plateau in the south, in the form of horsts. Subsequently, before the North Anatolian fault reached the region, it formed deformation structures under the effect of dextral shear in a wide zone in the Marmara region. This tectonic regime was ended when the North Anatolian fault reached and cut the Marmara Sea region in the Latest Quaternary.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70012950","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 : 2023-01-01DOI: 10.31577/geolcarp.2023.04
D. Harlov, A. van den Kerkhof, B. Haunschmidt, F. Finger
: The Weinsberg granite, a coarse-grained biotite granite with abundant K-feldspar megacrystals, is the volumetrically dominant and most characteristic granite type of the late-Variscan Moldanubian Batholith in the Moldanubian zone of the Bohemian Massif. In the western batholith area, a local orthopyroxene-bearing variant (charnockite) of the Weinsberg granite has been identified and given the name of the Sarleinsbach quartz-monzodiorite in previous studies. Whole rock analysis of the charnockite and the relatively mafic Weinsberg granite in the immediate neighbor-hood show no significant geochemical differences with respect to either the major or trace elements. The mineralogy and petrology of the charnockite and surrounding granite are the same except for the presence of orthopyroxene ± clino - pyroxene in the charnockite. In addition, the charnockite is characterized by the presence of dark grey, glassy orthoclase megacrysts with only some partial conversion to microcline, whereas in the granite the K-feldspar megacrysts consist of white microcline. The Fe–Mg silicates in the charnockite (orthopyroxene, clinopyroxene, amphibole, and biotite) are relatively Fe-rich (X Fe = 0.6–0.7) whereas the plagioclase is more albitic (X Ab = 0.6) than anorthitic. Fluid inclusions from the granite and associated charnockite are investigated and the results compared. The basic conclusion is that the magma responsible for the granite was dominated by an H 2 O-rich fluid with a CaCl 2 component. The magma responsible for the charnockite was dominated by a CO 2 -rich fluid with a minor NaCl component, which lowered the H 2 O activity sufficiently below 1 such that orthopyroxene ± clinopyroxene was the stable Fe–Mg silicate phase during crystallization as opposed to the biotite in the granite. Taking into account that CO 2 -rich and H 2 O-rich fluids are immiscible in the presence of NaCl and CaCl 2 over the P–T range of the overall crust, the implication is that in granitoid melts, if CO 2 is present, there will be regions dominated by CO 2 and regions dominated by H 2 O. The extent of either region will be determined by the overall CO 2 /H 2 O ratio in the melt. In the CO 2 -dominated regions, the H 2 O activity could be sufficiently lowered such that orthopyroxene is the stable Fe–Mg silicate phase during crystallization, though this will also be dependent on the Fe/Mg ratio of these phases and the overall whole rock chemistry of the melt. In addition to incipient solid state charnockitization, commonly seen in the Archean terranes of southern India and elsewhere, this suggests that a certain subset of granites and granitoids worldwide should have patches and/or limited areas of charnockite if the amount of CO 2 present in the original magma goes above a certain fraction.
Weinsberg花岗岩是一种粗粒黑云母花岗岩，具有丰富的钾长石巨晶，是波希米亚地块摩尔多瑙河带晚瓦里斯坎摩尔多瑙河基岩中体积占主导地位和最具特色的花岗岩类型。在西部岩基区，发现了温斯伯格花岗岩的一种局部含正辉石岩变种(charnockite)，前人将其命名为Sarleinsbach石英-二黄长岩。对其附近的绿硝子岩和相对基性较强的温斯伯格花岗岩进行全岩分析，发现其主量元素和微量元素在地球化学上均无显著差异。除绿砂砾岩中存在正辉石±斜辉石外，绿砂砾岩及其周围花岗岩的矿物学和岩石学基本相同。此外，绿帘石的特点是存在深灰色的玻璃状正长石巨晶，只有部分转化为微斜晶，而花岗岩中的钾长石巨晶则由白色微斜晶组成。绿辉石(正辉石、斜辉石、角闪石和黑云母)中的Fe- mg硅酸盐相对富铁(X Fe = 0.6 ~ 0.7)，而斜长石中的钠长石(X Ab = 0.6)比斜长石中的钠长石多。研究了花岗岩及其伴生绿帘岩的流体包裹体，并对结果进行了比较。得出的基本结论是，形成花岗岩的岩浆主要是一种含cacl2成分的富h2o流体。形成绿硝石的岩浆主要是一种含少量NaCl成分的富CO 2流体，它使h2o活度降低到1以下，从而使正辉石±斜辉石在结晶过程中成为稳定的Fe-Mg硅酸盐相，而不是花岗岩中的黑云母。考虑到在整个地壳的P-T范围内，NaCl和cacl2存在时，富co2流体和富h2o流体是不混溶的，这意味着在花岗岩类熔体中，如果有co2存在，就会有以co2为主的区域和以h2o为主的区域，这两个区域的程度将由熔体中总的co2 / h2o比值决定。在CO 2占主导地位的区域，h2o活性可以充分降低，使正辉石在结晶过程中成为稳定的Fe - Mg硅酸盐相，尽管这也取决于这些相的Fe/Mg比和熔体的整体岩石化学性质。除了在印度南部和其他地方的太古宙地质体中常见的早期固态炭屑化外，这表明，如果原始岩浆中CO 2的含量超过一定比例，那么世界范围内的某些花岗岩和花岗岩类应该具有斑块和/或有限区域的炭屑岩。
{"title":"Genesis of a synmagmatic charnockite associated with the Weinsberg granite, southern Bohemian Batholith, northern Austria","authors":"D. Harlov, A. van den Kerkhof, B. Haunschmidt, F. Finger","doi":"10.31577/geolcarp.2023.04","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.04","url":null,"abstract":": The Weinsberg granite, a coarse-grained biotite granite with abundant K-feldspar megacrystals, is the volumetrically dominant and most characteristic granite type of the late-Variscan Moldanubian Batholith in the Moldanubian zone of the Bohemian Massif. In the western batholith area, a local orthopyroxene-bearing variant (charnockite) of the Weinsberg granite has been identified and given the name of the Sarleinsbach quartz-monzodiorite in previous studies. Whole rock analysis of the charnockite and the relatively mafic Weinsberg granite in the immediate neighbor-hood show no significant geochemical differences with respect to either the major or trace elements. The mineralogy and petrology of the charnockite and surrounding granite are the same except for the presence of orthopyroxene ± clino - pyroxene in the charnockite. In addition, the charnockite is characterized by the presence of dark grey, glassy orthoclase megacrysts with only some partial conversion to microcline, whereas in the granite the K-feldspar megacrysts consist of white microcline. The Fe–Mg silicates in the charnockite (orthopyroxene, clinopyroxene, amphibole, and biotite) are relatively Fe-rich (X Fe = 0.6–0.7) whereas the plagioclase is more albitic (X Ab = 0.6) than anorthitic. Fluid inclusions from the granite and associated charnockite are investigated and the results compared. The basic conclusion is that the magma responsible for the granite was dominated by an H 2 O-rich fluid with a CaCl 2 component. The magma responsible for the charnockite was dominated by a CO 2 -rich fluid with a minor NaCl component, which lowered the H 2 O activity sufficiently below 1 such that orthopyroxene ± clinopyroxene was the stable Fe–Mg silicate phase during crystallization as opposed to the biotite in the granite. Taking into account that CO 2 -rich and H 2 O-rich fluids are immiscible in the presence of NaCl and CaCl 2 over the P–T range of the overall crust, the implication is that in granitoid melts, if CO 2 is present, there will be regions dominated by CO 2 and regions dominated by H 2 O. The extent of either region will be determined by the overall CO 2 /H 2 O ratio in the melt. In the CO 2 -dominated regions, the H 2 O activity could be sufficiently lowered such that orthopyroxene is the stable Fe–Mg silicate phase during crystallization, though this will also be dependent on the Fe/Mg ratio of these phases and the overall whole rock chemistry of the melt. In addition to incipient solid state charnockitization, commonly seen in the Archean terranes of southern India and elsewhere, this suggests that a certain subset of granites and granitoids worldwide should have patches and/or limited areas of charnockite if the amount of CO 2 present in the original magma goes above a certain fraction.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70012992","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 : 2023-01-01DOI: 10.31577/geolcarp.2023.02
W. Schwarzhans, A. Grizelj, M. Milošević, Valentina Hajek-Tadesse, K. Bakrač, I. Galović, L. Badurina, Tomislav Kurečić, L. Wacha, B. Šegvić, M. Matošević, Ana Čaić-Janković, Radovan Avanić
: A bentonite clay layer is documented in the Sutla-II column in the Hrvatsko Zagorje Basin, which is a part of the south-western marginal belt of the Pannonian Basin System. The origin of the clay is attributed to the alteration of felsic to intermediate volcanic ash, which had been deposited between horizontally-laminated marls in a marine environment. Provenance analysis indicates that the marls were sourced from mixed, dominantly-felsic source rocks. Smectite present in the marls is therefore not solely of terrigenous origin and may also be related to volcanic ash weathering. Based on the fossil content, an inference has been made suggesting Early Sarmatian age of the sediment hosting the bentonite clay intercalation. The sedimentological and palaeontological data are in favour of the sedimentation at an inner shelf area marked by unstable palaeoenvironmental conditions. The upper part of the Sutla-II column was deposited in the high-energy environment consisting of impure biocalcarenite and biocalcrudite coupled with fossiliferous litharenite, which all mark an intensive redeposition of older rocks and fossiliferous formations. The bentonite clay likely originated from distant tephra sourced from volcanic eruptions, presumably located in the north-eastern part of the Carpathian–Pannonian Region during the post-rift stage of the back-arc Pannonian Basin System development.
{"title":"Evidence of Early Sarmatian volcanism in the Hrvatsko Zagorje Basin, Croatia: Mineralogical, geochemical and biostratigraphic approaches","authors":"W. Schwarzhans, A. Grizelj, M. Milošević, Valentina Hajek-Tadesse, K. Bakrač, I. Galović, L. Badurina, Tomislav Kurečić, L. Wacha, B. Šegvić, M. Matošević, Ana Čaić-Janković, Radovan Avanić","doi":"10.31577/geolcarp.2023.02","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.02","url":null,"abstract":": A bentonite clay layer is documented in the Sutla-II column in the Hrvatsko Zagorje Basin, which is a part of the south-western marginal belt of the Pannonian Basin System. The origin of the clay is attributed to the alteration of felsic to intermediate volcanic ash, which had been deposited between horizontally-laminated marls in a marine environment. Provenance analysis indicates that the marls were sourced from mixed, dominantly-felsic source rocks. Smectite present in the marls is therefore not solely of terrigenous origin and may also be related to volcanic ash weathering. Based on the fossil content, an inference has been made suggesting Early Sarmatian age of the sediment hosting the bentonite clay intercalation. The sedimentological and palaeontological data are in favour of the sedimentation at an inner shelf area marked by unstable palaeoenvironmental conditions. The upper part of the Sutla-II column was deposited in the high-energy environment consisting of impure biocalcarenite and biocalcrudite coupled with fossiliferous litharenite, which all mark an intensive redeposition of older rocks and fossiliferous formations. The bentonite clay likely originated from distant tephra sourced from volcanic eruptions, presumably located in the north-eastern part of the Carpathian–Pannonian Region during the post-rift stage of the back-arc Pannonian Basin System development.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"338 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70013195","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 : 2023-01-01DOI: 10.31577/geolcarp.2023.05
N. Bonev, Zornitsa Dotseva, P. Filipov
: Metamorphosed mafic ophiolitic rocks in the metamorphic section of the eastern Rhodope Massif in Bulgaria and Greece are important for understanding the oceanic lithosphere fragments, which have been involved in Alpine tectonic–metamorphic processes. Petrography and mineral compositions of the meta-mafic rocks (mostly gabbro–basalt to minor diorite–andesite) point to main amphibolite-facies overprint, which strongly obliterated the primary textures, and the original igneous grain-sizes are partly preserved only of the plagioclase. The meta-mafic rocks are classified as low-K and low- to high-Ti tholeiitic affinity igneous protoliths of basaltic to andesitic compositions, in which high-Ti and low-Ti groups are identified on the basis of Ti concentrations. They also differ with respect to trace element and REE characteristics. A complex chemistry of high-Ti group indicates an origin primarily from MORB mantle source, subsequently modified by subduction-zone derived LILE- and REE-enriched melts and contribution of HFSE-enriched component that produce the oceanic island tholeiites. The low-Ti group displays IAT affinity, with clearly defined subduction-related component demonstrated by LILE enrichment, HFSE and HREE depletion relative to N-MORB and negative Nb and Ti anomalies, all indicative for an island arc petrogenesis. A single dunite sample studied also displays geochemical characteristics of the low-Ti group meta-mafic rocks. Geochemical diversity of the meta-basic rocks with MORB, transitional MORB/IAT and IAT affinities hints their supra-subduction zone (SSZ) origin in an island arc/ back-arc system, with identifiable arc-related and rifting/sea-floor spreading magmatic products represented by the low-Ti and high-Ti groups, respectively. At present, the available Middle-Late Paleozoic/Early Triassic radiometric ages of the meta-mafic rocks protoliths predominate over the Early Paleozoic ages, which suggests that the development of the inferred arc/back-arc system relates mostly to the ocean-floor magmatic evolution of the Paleotethyan realm.
{"title":"Geochemistry and tectonic significance of metamorphosed mafic ophiolitic rocks in the upper high-grade basement unit of the eastern Rhodope Massif (Bulgaria–Greece)","authors":"N. Bonev, Zornitsa Dotseva, P. Filipov","doi":"10.31577/geolcarp.2023.05","DOIUrl":"https://doi.org/10.31577/geolcarp.2023.05","url":null,"abstract":": Metamorphosed mafic ophiolitic rocks in the metamorphic section of the eastern Rhodope Massif in Bulgaria and Greece are important for understanding the oceanic lithosphere fragments, which have been involved in Alpine tectonic–metamorphic processes. Petrography and mineral compositions of the meta-mafic rocks (mostly gabbro–basalt to minor diorite–andesite) point to main amphibolite-facies overprint, which strongly obliterated the primary textures, and the original igneous grain-sizes are partly preserved only of the plagioclase. The meta-mafic rocks are classified as low-K and low- to high-Ti tholeiitic affinity igneous protoliths of basaltic to andesitic compositions, in which high-Ti and low-Ti groups are identified on the basis of Ti concentrations. They also differ with respect to trace element and REE characteristics. A complex chemistry of high-Ti group indicates an origin primarily from MORB mantle source, subsequently modified by subduction-zone derived LILE- and REE-enriched melts and contribution of HFSE-enriched component that produce the oceanic island tholeiites. The low-Ti group displays IAT affinity, with clearly defined subduction-related component demonstrated by LILE enrichment, HFSE and HREE depletion relative to N-MORB and negative Nb and Ti anomalies, all indicative for an island arc petrogenesis. A single dunite sample studied also displays geochemical characteristics of the low-Ti group meta-mafic rocks. Geochemical diversity of the meta-basic rocks with MORB, transitional MORB/IAT and IAT affinities hints their supra-subduction zone (SSZ) origin in an island arc/ back-arc system, with identifiable arc-related and rifting/sea-floor spreading magmatic products represented by the low-Ti and high-Ti groups, respectively. At present, the available Middle-Late Paleozoic/Early Triassic radiometric ages of the meta-mafic rocks protoliths predominate over the Early Paleozoic ages, which suggests that the development of the inferred arc/back-arc system relates mostly to the ocean-floor magmatic evolution of the Paleotethyan realm.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70013039","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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