Pub Date : 2021-09-20DOI: 10.31577/geolcarp.72.4.1
R. Yadav, D. Prakash, Swapnil Kumar Rai, Manoj K. Yadav, Pradip Kumar Singh, S. Jaiswal
{"title":"DECOMPRESSION TEXTURES IN GARNET–CORDIERITE GNEISS FROM KOSAVANKOVILPATTI, SOUTHERN INDIA: CONSTRAINTS FROM REACTION TEXTURES AND PHASE EQUILIBRIA MODELLING","authors":"R. Yadav, D. Prakash, Swapnil Kumar Rai, Manoj K. Yadav, Pradip Kumar Singh, S. Jaiswal","doi":"10.31577/geolcarp.72.4.1","DOIUrl":"https://doi.org/10.31577/geolcarp.72.4.1","url":null,"abstract":"","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46207557","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 : 2021-09-20DOI: 10.31577/geolcarp.72.4.3
G. Jovanović, Dragana Đurić, S. Vrabac, S. Ćorić, Jovica Jovanović, Zoran Bojić
{"title":"New biostratigraphic interpretation of the Middle Miocene (Badenian) transgression in the southern margin of the Pannonian Basin (Hrvaćani, northern Bosnia, Central Paratethys), based on the fossil assemblages","authors":"G. Jovanović, Dragana Đurić, S. Vrabac, S. Ćorić, Jovica Jovanović, Zoran Bojić","doi":"10.31577/geolcarp.72.4.3","DOIUrl":"https://doi.org/10.31577/geolcarp.72.4.3","url":null,"abstract":"","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42815318","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 : 2021-09-20DOI: 10.31577/geolcarp.72.4.5
Milan Kohút, Sarah C. Sherlock, Alison M. Halton
In situ 40Ar–39Ar UV laser ablation dating of the Carpathian C1 obsidians from the Slovakian part of the Zemplín – Tokaj area yielded new 40Ar–39Ar obsidian glass ages that fall in a narrow time interval of 12.07 ± 0.37 to 11.44 ± 0.39 Ma. This indicate that most of the Zemplín obsidian findings come from one short-time monogenic volcano, forming part of a long-lasting volcanism over the 15–10 Ma period. Chemical compositions of the Carpathian C1 obsidians clearly indicate common similarities between all examined localities (Brehov, Cejkov, Hraň, and Viničky). Geochemically, these obsidians belong to the silica-rich, peraluminous, high-potassium, calc-alkaline rhyolite series volcanic rocks of ferroan character. They were derived by multi-stage magmatic processes, from mixed mantle and crustal sources, and generated during subduction in a volcanic arc tectonic setting. The primary basaltic magma formed from the melting of the lower crustal source at the mantle/crust boundary. Subsequent formation of melt reservoirs in the middle and upper crust, accompanied by secondary melting of the surrounding rocks with continual addition of ascending melt, and repeated processes of assimilation and fractionation produced rhyolitic rocks with obsidians in the Zemplínske vrchy Mts.
{"title":"The 40Ar–39Ar dating and geochemistry of the Carpathian C1 obsidians (Zemplín, Slovakia)","authors":"Milan Kohút, Sarah C. Sherlock, Alison M. Halton","doi":"10.31577/geolcarp.72.4.5","DOIUrl":"https://doi.org/10.31577/geolcarp.72.4.5","url":null,"abstract":"In situ 40Ar–39Ar UV laser ablation dating of the Carpathian C1 obsidians from the Slovakian part of the Zemplín – Tokaj area yielded new 40Ar–39Ar obsidian glass ages that fall in a narrow time interval of 12.07 ± 0.37 to 11.44 ± 0.39 Ma. This indicate that most of the Zemplín obsidian findings come from one short-time monogenic volcano, forming part of a long-lasting volcanism over the 15–10 Ma period. Chemical compositions of the Carpathian C1 obsidians clearly indicate common similarities between all examined localities (Brehov, Cejkov, Hraň, and Viničky). Geochemically, these obsidians belong to the silica-rich, peraluminous, high-potassium, calc-alkaline rhyolite series volcanic rocks of ferroan character. They were derived by multi-stage magmatic processes, from mixed mantle and crustal sources, and generated during subduction in a volcanic arc tectonic setting. The primary basaltic magma formed from the melting of the lower crustal source at the mantle/crust boundary. Subsequent formation of melt reservoirs in the middle and upper crust, accompanied by secondary melting of the surrounding rocks with continual addition of ascending melt, and repeated processes of assimilation and fractionation produced rhyolitic rocks with obsidians in the Zemplínske vrchy Mts.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42129767","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 : 2021-09-20DOI: 10.31577/geolcarp.72.4.4
K. Chruszcz-Lipska, Marek Leszek Solecki, Bartosz Trzewik, M. Maruta, Joanna Wartak, Danuta Zagrajczuk
{"title":"IR spectroscopy as a fast method of determining carbonate content in the Sarmatian–Badenian sandstone reservoirs: A case study from the Carpathian Foredeep (Poland)","authors":"K. Chruszcz-Lipska, Marek Leszek Solecki, Bartosz Trzewik, M. Maruta, Joanna Wartak, Danuta Zagrajczuk","doi":"10.31577/geolcarp.72.4.4","DOIUrl":"https://doi.org/10.31577/geolcarp.72.4.4","url":null,"abstract":"","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44141310","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 : 2021-07-28DOI: 10.31577/geolcarp.72.3.2
I. Peytcheva, A. von Quadt, V. Kostov-Kytin, M. Kadiyski, Milen Stavrev
The economic significance of pegmatites as a source of strategic rare metals for high-tech products and green energy motivated the present study on Ta–Nb oxides from Vishteritsa rare-element beryl–columbite LCT pegmatites of the Rila–West Rhodopes Batholith in the Western Rhodopes, Bulgaria. Here, we present the first U/Pb age data from columbite with application of the LA–ICP–MS U–Pb technique and a new X36 columbite standard reference material. The obtained Concordia age of 47.57 ± 0.32 Ma with a small spread of the individual 206Pb/238U ages between 45 and 51.3 Ma argues for Early Eocene magmatism and pegmatite formation. The host granite of the rare-element pegmatites is dated 51.94 ± 0.61 Ma with LA–ICP–MS U–Pb technique on zircon and suggests a fertile Early Eocene magmatic period in the Western Rhodopes. EPMA data for the composition of the columbite is used to refine the formula of the mineral (Mn0.554Fe0.427U0.006)0.987(Nb1.826Ta0.085Ti0.116)2.03O6 and define it as columbite-(Mn). Application of the in-situ LA–ICP–MS data technique establishes a series of typical trace elements (Ti, U, Zr, Hf, Y, W, and Zn) that are usually found in content above 500 ppm. The studied columbite is enriched in heavy rare earth elements (HREE sum: 306–697 ppm) and depleted in light REE and Eu. These geochemical characteristics are collectively interpreted as evidence for crystallization from highly fractionated fluid-rich magma. High UO2 content reaching 0.89 wt. % is characteristic for the Vishteritsa columbite. The decrease of U proximal to cracks and in outer crystal zones documents U-mobility during overprinting hydrothermal processes.
{"title":"U-Pb dating and composition of columbite from Vishteritsa: Implication for timing of granite magmatism and rare-element granitic pegmatites in the Western Rhodopes, Bulgaria","authors":"I. Peytcheva, A. von Quadt, V. Kostov-Kytin, M. Kadiyski, Milen Stavrev","doi":"10.31577/geolcarp.72.3.2","DOIUrl":"https://doi.org/10.31577/geolcarp.72.3.2","url":null,"abstract":"The economic significance of pegmatites as a source of strategic rare metals for high-tech products and green energy motivated the present study on Ta–Nb oxides from Vishteritsa rare-element beryl–columbite LCT pegmatites of the Rila–West Rhodopes Batholith in the Western Rhodopes, Bulgaria. Here, we present the first U/Pb age data from columbite with application of the LA–ICP–MS U–Pb technique and a new X36 columbite standard reference material. The obtained Concordia age of 47.57 ± 0.32 Ma with a small spread of the individual 206Pb/238U ages between 45 and 51.3 Ma argues for Early Eocene magmatism and pegmatite formation. The host granite of the rare-element pegmatites is dated 51.94 ± 0.61 Ma with LA–ICP–MS U–Pb technique on zircon and suggests a fertile Early Eocene magmatic period in the Western Rhodopes. EPMA data for the composition of the columbite is used to refine the formula of the mineral (Mn0.554Fe0.427U0.006)0.987(Nb1.826Ta0.085Ti0.116)2.03O6 and define it as columbite-(Mn). Application of the in-situ LA–ICP–MS data technique establishes a series of typical trace elements (Ti, U, Zr, Hf, Y, W, and Zn) that are usually found in content above 500 ppm. The studied columbite is enriched in heavy rare earth elements (HREE sum: 306–697 ppm) and depleted in light REE and Eu. These geochemical characteristics are collectively interpreted as evidence for crystallization from highly fractionated fluid-rich magma. High UO2 content reaching 0.89 wt. % is characteristic for the Vishteritsa columbite. The decrease of U proximal to cracks and in outer crystal zones documents U-mobility during overprinting hydrothermal processes.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47613460","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 : 2021-07-20DOI: 10.31577/geolcarp.72.2.1
J. Vozár, V. Bezák, František Marko
We present the crustal-scale geophysical model based on the magnetotelluric method focused on 3-D model¬ling of the seismic 2T profile crossing the major Western Carpathian tectonic units in central Slovakia. The results of the 3-D modelling show substantial improvement in previous 2-D models of deep crustal structure in central Slovakia, mainly of the physically distinct tectonic segments and major geo-electrical regional structures like the zone of the Carpathian Conductivity Anomaly, which indicates the occurrence of the large-scale shear zone in the contact zone of the European platform and Inner Western Carpathians. High detail geo-electrical data in 3-D magnetotelluric (MT) cross section also allowed a better interpretation of other conductive anomalies. In the final integ-rated interpretation (combination of 3-D geo-electrical model, gravity data and seismic reflectors), it is shown that frontal part of the Inner Western Carpathians plate exhibits the transpressional tectonic style of the back-thrust Outer Western Carpathians (Flysch Belt) and Pieniny Klippen Belt units over the progressing Inner Western Carpathian thrust wedge. These back-thrusts form the southern branch of the accretionary structural fan – a large-scale transpressional flower structure typical mainly but not only for oblique con-vergent regimes. The southernmost segment of the profile with high whole-crust conductivity due to a higher heat flow caused by young volcanic activity indicates partial melting in the middle and lower crust.
{"title":"Three-dimensional magnetotelluric model along seismic profile 2T: An improved view on crustal structure in central Slovakia (Western Carpathians)","authors":"J. Vozár, V. Bezák, František Marko","doi":"10.31577/geolcarp.72.2.1","DOIUrl":"https://doi.org/10.31577/geolcarp.72.2.1","url":null,"abstract":"We present the crustal-scale geophysical model based on the magnetotelluric method focused on 3-D model¬ling of the seismic 2T profile crossing the major Western Carpathian tectonic units in central Slovakia. The results of the 3-D modelling show substantial improvement in previous 2-D models of deep crustal structure in central Slovakia, mainly of the physically distinct tectonic segments and major geo-electrical regional structures like the zone of the Carpathian Conductivity Anomaly, which indicates the occurrence of the large-scale shear zone in the contact zone of the European platform and Inner Western Carpathians. High detail geo-electrical data in 3-D magnetotelluric (MT) cross section also allowed a better interpretation of other conductive anomalies. In the final integ-rated interpretation (combination of 3-D geo-electrical model, gravity data and seismic reflectors), it is shown that frontal part of the Inner Western Carpathians plate exhibits the transpressional tectonic style of the back-thrust Outer Western Carpathians (Flysch Belt) and Pieniny Klippen Belt units over the progressing Inner Western Carpathian thrust wedge. These back-thrusts form the southern branch of the accretionary structural fan – a large-scale transpressional flower structure typical mainly but not only for oblique con-vergent regimes. The southernmost segment of the profile with high whole-crust conductivity due to a higher heat flow caused by young volcanic activity indicates partial melting in the middle and lower crust.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70013053","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 : 2021-03-02DOI: 10.31577/GEOLCARP.72.1.3
M. Hencz, T. Biró, Z. Cseri, D. Karátson, E. Márton, K. Németh, A. Szakács, Z. Pécskay, István János Kovács
Detailed investigation of a Lower Miocene Plinian pyroclastic sequence that crops out in the Bükk Foreland Volcanic Area (BFVA) in Northern Hungary is presented here. The studied eruptive products are part of a ca. 50 metres thick pyroclastic succession comprising of a basal ignimbrite that is covered by stratified pyroclastic unit including a topmost ignimbrite (Mangó ignimbrite unit, part of the Lower Pyroclastic Complex). The investigated pyroclastic unit is part of the Mangó ignimbrite unit, and consists of a pyroclastic fallout deposit, a ground-surge deposit, and an ignimbrite, all indicating a complete Plinian eruption phase. This pyroclastic succession has been identified in three locations, which crops out along a ~20 km long, SW–NE transect in the BFVA (two in the western, and one in the eastern part). The pyroclastic rocks in these sites are correlated well on the basis of the lithologically and texturally similar layers and their identical field volcanological properties. The correlation is also supported by the paleomagnetic signature of the two ignimbrites (upper ignimbrite – declination: 275–302°, lower ignimbrite with overprint magnetization – declination: 320–334°). The paleomagnetic directions of the stratigraphically upper ignimbrite suggest that this sequence belongs to the oldest known pyroclastic rock assemblages of the BFVA (Lower Pyroclastic Complex, deposited between 18.5 and 21 Ma according to previously published K/Ar dating results in good agreement with paleomagnetic measurements). Based on proximal-to-distal variations in the grain size of the pyroclastic fallout deposit (with maximal thickness is 71 cm), a potential source region to the east (or northeast, or southeast) of the BFVA has been inferred in a relatively close distance (~5–15 km). The (north)eastward-located source region is also supported by comparison of the characteristics of the studied fallout deposit with the spatial distribution of selected Plinian fallout tephra from worldwide examples using their digitalized isopach maps.
{"title":"A Lower Miocene pyroclastic-fall deposit from the Bükk Foreland Volcanic Area, Northern Hungary: Clues for an eastward-located source","authors":"M. Hencz, T. Biró, Z. Cseri, D. Karátson, E. Márton, K. Németh, A. Szakács, Z. Pécskay, István János Kovács","doi":"10.31577/GEOLCARP.72.1.3","DOIUrl":"https://doi.org/10.31577/GEOLCARP.72.1.3","url":null,"abstract":"Detailed investigation of a Lower Miocene Plinian pyroclastic sequence that crops out in the Bükk Foreland Volcanic Area (BFVA) in Northern Hungary is presented here. The studied eruptive products are part of a ca. 50 metres thick pyroclastic succession comprising of a basal ignimbrite that is covered by stratified pyroclastic unit including a topmost ignimbrite (Mangó ignimbrite unit, part of the Lower Pyroclastic Complex). The investigated pyroclastic unit is part of the Mangó ignimbrite unit, and consists of a pyroclastic fallout deposit, a ground-surge deposit, and an ignimbrite, all indicating a complete Plinian eruption phase. This pyroclastic succession has been identified in three locations, which crops out along a ~20 km long, SW–NE transect in the BFVA (two in the western, and one in the eastern part). The pyroclastic rocks in these sites are correlated well on the basis of the lithologically and texturally similar layers and their identical field volcanological properties. The correlation is also supported by the paleomagnetic signature of the two ignimbrites (upper ignimbrite – declination: 275–302°, lower ignimbrite with overprint magnetization – declination: 320–334°). The paleomagnetic directions of the stratigraphically upper ignimbrite suggest that this sequence belongs to the oldest known pyroclastic rock assemblages of the BFVA (Lower Pyroclastic Complex, deposited between 18.5 and 21 Ma according to previously published K/Ar dating results in good agreement with paleomagnetic measurements). Based on proximal-to-distal variations in the grain size of the pyroclastic fallout deposit (with maximal thickness is 71 cm), a potential source region to the east (or northeast, or southeast) of the BFVA has been inferred in a relatively close distance (~5–15 km). The (north)eastward-located source region is also supported by comparison of the characteristics of the studied fallout deposit with the spatial distribution of selected Plinian fallout tephra from worldwide examples using their digitalized isopach maps.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47354874","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 : 2021-03-02DOI: 10.31577/GEOLCARP.72.1.5
Šárka Koníčková, Z. Losos, S. Houzar, D. Všianský
Massive quartz–chalcedony ± opal nodules (“plasma” in gemology) represent a specific silica variety, which occurs in the laterite-like residues of pre-Miocene paleo-weathering of ultramafites in western Moravia (Moldanubian Zone, Bohemian Massif). These zonal silica nodules (ZSN) tend to have concentric texture with a dark green to greenbrown core, pale green margin and a narrow white rim (outer surface zone). The most typical microscopic feature of ZSN is vermiform microstructure particularly in the two outer zones. Individual zones consist of microto non-crystalline SiO2 polymorphs with variable contents of H2O (quartz, chalcedony, moganite, opal-C/CT and opal-A). The predominant green colour is due to submicroscopic smectite pigment, while the brownish colour originated from decomposition of smectite to iron oxohydroxides. ZSN formed in subaerial, partially reducing conditions in the lower part of weathering crusts covering serpentinites. The whole process was preceded by component exchange (chloritization) along serpentinite – felsic rocks (granulite, migmatite, pegmatite veins) boundaries. The gradual silica migration and subsequent redistribution associated with the removal of aluminium, magnesium and iron led up to the formation of a zonal nodular texture dominated by SiO2 polymorphs. Newly formed minerals in micro-cavities and cracks of ZSN are represented by accessory pyrite and sporadic barite. Zonal silica nodules-bearing residues on serpentinites occur only in a narrow area which was originally covered by clay-sandy Miocene sediments of the Carpathian Foredeep in western Moravia. Probably late low-temperature fluid interaction between silicified serpentinite residuum (chlorite – montmorillonite saprolite) and marine sediments may be the main factor controlling formation of ZSN.
{"title":"Specific green zonal silica nodules of serpentinite weathering: unusual products of silicification in laterite-like residuum (Moldanubian Zone, Bohemian Massif)","authors":"Šárka Koníčková, Z. Losos, S. Houzar, D. Všianský","doi":"10.31577/GEOLCARP.72.1.5","DOIUrl":"https://doi.org/10.31577/GEOLCARP.72.1.5","url":null,"abstract":"Massive quartz–chalcedony ± opal nodules (“plasma” in gemology) represent a specific silica variety, which occurs in the laterite-like residues of pre-Miocene paleo-weathering of ultramafites in western Moravia (Moldanubian Zone, Bohemian Massif). These zonal silica nodules (ZSN) tend to have concentric texture with a dark green to greenbrown core, pale green margin and a narrow white rim (outer surface zone). The most typical microscopic feature of ZSN is vermiform microstructure particularly in the two outer zones. Individual zones consist of microto non-crystalline SiO2 polymorphs with variable contents of H2O (quartz, chalcedony, moganite, opal-C/CT and opal-A). The predominant green colour is due to submicroscopic smectite pigment, while the brownish colour originated from decomposition of smectite to iron oxohydroxides. ZSN formed in subaerial, partially reducing conditions in the lower part of weathering crusts covering serpentinites. The whole process was preceded by component exchange (chloritization) along serpentinite – felsic rocks (granulite, migmatite, pegmatite veins) boundaries. The gradual silica migration and subsequent redistribution associated with the removal of aluminium, magnesium and iron led up to the formation of a zonal nodular texture dominated by SiO2 polymorphs. Newly formed minerals in micro-cavities and cracks of ZSN are represented by accessory pyrite and sporadic barite. Zonal silica nodules-bearing residues on serpentinites occur only in a narrow area which was originally covered by clay-sandy Miocene sediments of the Carpathian Foredeep in western Moravia. Probably late low-temperature fluid interaction between silicified serpentinite residuum (chlorite – montmorillonite saprolite) and marine sediments may be the main factor controlling formation of ZSN.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44873638","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 : 2021-03-02DOI: 10.31577/GEOLCARP.72.1.1
L. Tomassetti, L. Petracchini, M. Brandano, G. Mascaro, D. Scrocca
The characterization and comprehension of buried reservoirs receive remarkable benefits from detailed studies of outcropping analogues which help to define the architecture of the buried sedimentary units and their petrophysical features. In particular, modern 3D techniques of geological data analysis can better constrain the geological mapping process and reveal the geometry of the sedimentary units with complex lateral and vertical relationships. By means of the 3D Move software, we define the sedimentological and stratigraphical relationships between lithostratigraphic units of the Bolognano Formation, outcropping in the northernmost sector of the Majella Mountain (Central Apennines, Italy). The study area belongs to the Apulian carbonate platform and the Majella Mountain represents the northward outcropping portion of its margin. The sedimentary succession of the Majella Mountain consists of Upper Jurassic to upper Miocene limestone and dolostone deposits. In the investigated area, outcropping deposits mainly belong to the Oligo–Miocene Bolognano Formation characterized by five lithofacies associations and representing a carbonate ramp developed in a warm subtropical depositional environment within the oligophotic to aphotic zone. The Bolognano Fm. represents, due to its specific hydraulic properties (e.g. porosity and permeability), an outcropping analogue of worldwide common reservoirs (i.e. porous calcarenite deposits of a carbonate ramp formed by benthic foraminifera such as lepidocyclinids, nummulitids, red algae, corals). In the study area, several geological units of the Bolognano Fm. are characterized by abundant hydrocarbon (bitumen) occurrences infilled within the high-porosity of the cross-bedded calcarenites ascribed to the Chattian and Burdigalian interval. The geological field mapping of the area and the visualization of the geological data in a 3D environment show that the unit formed by mid-ramp calcarenites (Lepidocyclina calcarenites 2 unit, Chattian–Burdigalian) increases in thickness towards the NE (basinward) direction as a consequence of sediment shedding from inner ramp. Our study illustrates how the geological mapping and the visualization and analysis of geological data in a 3D environment of the northernmost sector of the Majella Mountain confirms depositional models of the Bolognano Formation and represents a valid tool for the characterization of the lateral stratigraphic relationships within this formation, and hence of its potential hydrocarbon occurrences.
{"title":"Stratigraphical and sedimentological relationships of the Bolognano Formation (Oligocene–Miocene, Majella Mountain, Central Apennines, Italy) revealed by geological mapping and 3D visualizations","authors":"L. Tomassetti, L. Petracchini, M. Brandano, G. Mascaro, D. Scrocca","doi":"10.31577/GEOLCARP.72.1.1","DOIUrl":"https://doi.org/10.31577/GEOLCARP.72.1.1","url":null,"abstract":"The characterization and comprehension of buried reservoirs receive remarkable benefits from detailed studies of outcropping analogues which help to define the architecture of the buried sedimentary units and their petrophysical features. In particular, modern 3D techniques of geological data analysis can better constrain the geological mapping process and reveal the geometry of the sedimentary units with complex lateral and vertical relationships. By means of the 3D Move software, we define the sedimentological and stratigraphical relationships between lithostratigraphic units of the Bolognano Formation, outcropping in the northernmost sector of the Majella Mountain (Central Apennines, Italy). The study area belongs to the Apulian carbonate platform and the Majella Mountain represents the northward outcropping portion of its margin. The sedimentary succession of the Majella Mountain consists of Upper Jurassic to upper Miocene limestone and dolostone deposits. In the investigated area, outcropping deposits mainly belong to the Oligo–Miocene Bolognano Formation characterized by five lithofacies associations and representing a carbonate ramp developed in a warm subtropical depositional environment within the oligophotic to aphotic zone. The Bolognano Fm. represents, due to its specific hydraulic properties (e.g. porosity and permeability), an outcropping analogue of worldwide common reservoirs (i.e. porous calcarenite deposits of a carbonate ramp formed by benthic foraminifera such as lepidocyclinids, nummulitids, red algae, corals). In the study area, several geological units of the Bolognano Fm. are characterized by abundant hydrocarbon (bitumen) occurrences infilled within the high-porosity of the cross-bedded calcarenites ascribed to the Chattian and Burdigalian interval. The geological field mapping of the area and the visualization of the geological data in a 3D environment show that the unit formed by mid-ramp calcarenites (Lepidocyclina calcarenites 2 unit, Chattian–Burdigalian) increases in thickness towards the NE (basinward) direction as a consequence of sediment shedding from inner ramp. Our study illustrates how the geological mapping and the visualization and analysis of geological data in a 3D environment of the northernmost sector of the Majella Mountain confirms depositional models of the Bolognano Formation and represents a valid tool for the characterization of the lateral stratigraphic relationships within this formation, and hence of its potential hydrocarbon occurrences.","PeriodicalId":12545,"journal":{"name":"Geologica Carpathica","volume":"72 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41968198","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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