This study investigated the geochemistry, mineralogy, fluid inclusion, trace and rare earth element (REE) contents and Pb, O and S isotope results of the barites formed together with Pb-Zn deposits in the region. The Buyukkizilcik barite mineralization is located in the west part of Afsin, Turkey and it can be traced through 14 kilometers in NE-SW direction within the Yoncayolu and Cayderesi Formation. The thickness of these mineralized areas reaches 7-8 m, especially in the middle and eastern part of the ore zone. Mineralization is represented by barite-antimonite-fluorite in the western part, pyrite-chalcopyrite in the middle part and galena-sphalerite in the eastern part of the mineralized zone. Fluid inclusion studies indicate that these mineralizations are formed in the epithermal phase of hydrothermal period, with liquids having 4.5 to 2% NaCl salinity values and temperatures of 105 °C to 121 °C. The barite samples were collected from Buyukkizilcik mineralization area for analysis of major oxides, trace elements, and rare earth elements (REEs) using inductively coupled plasma mass spectrometry (ICP-MS). According to the results of the analysis, it is seen that total trace element contents change from 163 to 20458 ppm and ∑REE contents are between 4.31 and 14.4 ppm. The chondrite- normalized REE patterns of the studied barites exhibit trends decrease from LREE towards HREE and have negative Ce and negative Eu anomalies. The 206Pb/204Pb; 207Pb/204Pb and 208Pb/204Pb isotope values of galena vary between 17.20 and 19.96%o; 14.1 and 16.2%; and 35.4 and 41.9%, respectively. These isotope results show that these mineralizations were originated from upper crust materials. The δ34S values in Buyukkizilcik mineralizations range from 8.2 to 14.4‰. The barite mineralization was formed by hydrothermal activity and that the δ34S values indicate an epithermal phase. The δ18O values of barites are between 17.0 and 18.5‰ and these δ18O values show that the origin of the water displayed in the hydrothermal activity is magmatic and/or magmatic mixed with meteoric water. All results indicate that the barite mineralization was deposited as vein-type by hydrothermal solutions that are transported along fractures and fault zones within the Malatya Metamorphic complexes.
{"title":"Geochemical approach to the genesis of the Buyukkizilcik (Afsin) barite deposit, SE Turkey","authors":"Nevin Konakci, Ahmet Sasmaz","doi":"10.3301/IJG.2021.04","DOIUrl":"https://doi.org/10.3301/IJG.2021.04","url":null,"abstract":"This study investigated the geochemistry, mineralogy, fluid inclusion, trace and rare earth element (REE) contents and Pb, O and S isotope results of the barites formed together with Pb-Zn deposits in the region. The Buyukkizilcik barite mineralization is located in the west part of Afsin, Turkey and it can be traced through 14 kilometers in NE-SW direction within the Yoncayolu and Cayderesi Formation. The thickness of these mineralized areas reaches 7-8 m, especially in the middle and eastern part of the ore zone. Mineralization is represented by barite-antimonite-fluorite in the western part, pyrite-chalcopyrite in the middle part and galena-sphalerite in the eastern part of the mineralized zone. Fluid inclusion studies indicate that these mineralizations are formed in the epithermal phase of hydrothermal period, with liquids having 4.5 to 2% NaCl salinity values and temperatures of 105 °C to 121 °C. The barite samples were collected from Buyukkizilcik mineralization area for analysis of major oxides, trace elements, and rare earth elements (REEs) using inductively coupled plasma mass spectrometry (ICP-MS). According to the results of the analysis, it is seen that total trace element contents change from 163 to 20458 ppm and ∑REE contents are between 4.31 and 14.4 ppm. The chondrite- normalized REE patterns of the studied barites exhibit trends decrease from LREE towards HREE and have negative Ce and negative Eu anomalies. The 206Pb/204Pb; 207Pb/204Pb and 208Pb/204Pb isotope values of galena vary between 17.20 and 19.96%o; 14.1 and 16.2%; and 35.4 and 41.9%, respectively. These isotope results show that these mineralizations were originated from upper crust materials. The δ34S values in Buyukkizilcik mineralizations range from 8.2 to 14.4‰. The barite mineralization was formed by hydrothermal activity and that the δ34S values indicate an epithermal phase. The δ18O values of barites are between 17.0 and 18.5‰ and these δ18O values show that the origin of the water displayed in the hydrothermal activity is magmatic and/or magmatic mixed with meteoric water. All results indicate that the barite mineralization was deposited as vein-type by hydrothermal solutions that are transported along fractures and fault zones within the Malatya Metamorphic complexes.","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80587281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Akimbekova, P. Mancinelli, M. Pozo, C. Pauselli, G. Minelli, M. Barchi
In the present study, we perform a gravity modelling at crustal scale along the trace of the CROP-04 (on-shore) and M-6B (off-shore) deep seismic reflection profiles, crossing the Southern Apennines and the Southern Tyrrhenian Sea (Italy). Along the 321 km-long modelled profile, we investigate the crustal-scale sources for the observed gravity anomalies through a simplified model of the crust and upper mantle across both onshore and offshore areas.After a compelling review of the published Moho geometries in the area, that were retrieved from either active or passive seismic methods, we test them in the observed gravity field through forward modelling of the Bouguer gravity anomalies. The comparison between the different Moho interpretations highlights the major contributors to the observed Bouguer gravity at the crustal scale, defining a set of starting values of these parameters for our final model.The proposed model locates the westward flexure of the Adriatic Moho, mimicking the subduction of the Adriatic lithosphere beneath the Peri-Tyrrhenian block and locates the step between the western (Tyrrhenian) and the eastern (Adriatic) Moho beneath the Apennines range providing a valuable geometrical and compositional model at the crustal scale. The model depicts a typical oceanic-to-continental crust transition in the Tyrrhenian domain and represents a solid starting base for further detailed modelling across the area.
{"title":"Forward Modelling of Bouguer Anomalies along a transect of the Southern Apennines and the Southern Tyrrhenian Sea (Italy)","authors":"A. Akimbekova, P. Mancinelli, M. Pozo, C. Pauselli, G. Minelli, M. Barchi","doi":"10.3301/IJG.2021.03","DOIUrl":"https://doi.org/10.3301/IJG.2021.03","url":null,"abstract":"In the present study, we perform a gravity modelling at crustal scale along the trace of the CROP-04 (on-shore) and M-6B (off-shore) deep seismic reflection profiles, crossing the Southern Apennines and the Southern Tyrrhenian Sea (Italy). Along the 321 km-long modelled profile, we investigate the crustal-scale sources for the observed gravity anomalies through a simplified model of the crust and upper mantle across both onshore and offshore areas.After a compelling review of the published Moho geometries in the area, that were retrieved from either active or passive seismic methods, we test them in the observed gravity field through forward modelling of the Bouguer gravity anomalies. The comparison between the different Moho interpretations highlights the major contributors to the observed Bouguer gravity at the crustal scale, defining a set of starting values of these parameters for our final model.The proposed model locates the westward flexure of the Adriatic Moho, mimicking the subduction of the Adriatic lithosphere beneath the Peri-Tyrrhenian block and locates the step between the western (Tyrrhenian) and the eastern (Adriatic) Moho beneath the Apennines range providing a valuable geometrical and compositional model at the crustal scale. The model depicts a typical oceanic-to-continental crust transition in the Tyrrhenian domain and represents a solid starting base for further detailed modelling across the area.","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84432001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Calcari con Selce formation (CSf) is a low-porosity multilayer carbonate, partially dolomitized, formation that extensively crops out in the Lucania Apennine chain. This lithostratigraphic succession represents to depth a key formation concerning hydrocarbon exploration and a potential confined acquifer system. In this work we describe the structural features affecting the CSf related to burial and tectonic deformation with emphasis on normal faults related to post-orogenic extensional deformation. A field investigation led to recognition of background structures such as: i) strata-bounded sub-vertical fracture sets (OBj) and bedding-parallel solution seams (BPss), related to lithostatic load; and: ii) oblique-to-bedding solution seams (BOss) induced by syn-orogenic flexural slip. Furthermore, different sets of dolomitic veins extensively affect dolomitized parts of the CSf showing structural relationships with bedding interfaces. Localized low-angle normal faults (LANFs) post-dating the previous structures formed further anisotropies locally associated with sub- vertical fracture sets (SVfs). These structures, enhancing permeability within carbonate beds, promoted fluid compartmentalization. High- angle normal faults and associate fracture sets, characterized by well-connected features, mainly localized along the mature fault zones, further enhanced the permeability of the CSf allowing the development of preferential fluid-flow pathways moving parallel to the fault-zones, as inferred from the structure of calcite veins. This work provides an enhanced characterization of the fracture network affecting the CSf and represents a useful tool aimed at improving hydrological models for fluid circulation within fractured reservoirs.
Calcari con Selce地层(CSf)是一种低孔隙度多层碳酸盐，部分白云化，广泛生长在卢卡尼亚亚平宁链中。该岩性地层序列在深度上代表了油气勘探的关键地层和潜在的承压含水层系统。在本文中，我们描述了与埋藏和构造变形有关的影响CSf的构造特征，重点描述了与造山后伸展变形有关的正断层。通过现场调查，识别出以下背景结构:1)与静岩载荷有关的层界亚垂直裂缝集(OBj)和层理平行溶蚀缝(BPss);ii)同造山带弯曲滑移诱发的斜层状溶液层。此外，不同组的白云质脉广泛地影响着脑脊液的白云化部分，显示出与层理界面的结构关系。局部低角度正断层(LANFs)在之前的构造之后形成了进一步的各向异性，局部与亚垂直断裂集(SVfs)相关。这些构造提高了碳酸盐岩地层的渗透率，促进了流体的区域化。方解石脉结构表明，高角度正断层及其伴生裂缝组主要分布在成熟断裂带上，具有连通良好的特征，进一步增强了CSf的渗透性，有利于平行于断裂带的优先流体流动通道的发育。这项工作提供了影响CSf的裂缝网络的增强特征，并代表了一个有用的工具，旨在改进裂缝性储层内流体循环的水文模型。
{"title":"Structural investigation of background features and normal faults affecting the Calcari con Selce formation, Southern Apennines, Italy","authors":"R. Novellino, F. Bucci, E. Tavarnelli","doi":"10.3301/ijg.2020.31","DOIUrl":"https://doi.org/10.3301/ijg.2020.31","url":null,"abstract":"The Calcari con Selce formation (CSf) is a low-porosity multilayer carbonate, partially dolomitized, formation that extensively crops out in the Lucania Apennine chain. This lithostratigraphic succession represents to depth a key formation concerning hydrocarbon exploration and a potential confined acquifer system. In this work we describe the structural features affecting the CSf related to burial and tectonic deformation with emphasis on normal faults related to post-orogenic extensional deformation. A field investigation led to recognition of background structures such as: i) strata-bounded sub-vertical fracture sets (OBj) and bedding-parallel solution seams (BPss), related to lithostatic load; and: ii) oblique-to-bedding solution seams (BOss) induced by syn-orogenic flexural slip. Furthermore, different sets of dolomitic veins extensively affect dolomitized parts of the CSf showing structural relationships with bedding interfaces. Localized low-angle normal faults (LANFs) post-dating the previous structures formed further anisotropies locally associated with sub- vertical fracture sets (SVfs). These structures, enhancing permeability within carbonate beds, promoted fluid compartmentalization. High- angle normal faults and associate fracture sets, characterized by well-connected features, mainly localized along the mature fault zones, further enhanced the permeability of the CSf allowing the development of preferential fluid-flow pathways moving parallel to the fault-zones, as inferred from the structure of calcite veins. This work provides an enhanced characterization of the fracture network affecting the CSf and represents a useful tool aimed at improving hydrological models for fluid circulation within fractured reservoirs.","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86866874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We report on the first geochemical and mineralogical study of the Late Cretaceous black shales and black phyllites occurring within the basal portion of the “Scaglia toscana” and “Scisti sericitici” formations, respectively (Northern Apennines, northern Tuscany, Italy). The black shales occurring within the “Scaglia toscana” Formation are interbedded with red and greenish shales and form cm-thick layers; in some localities they are characterized by the occurrence of cm- sized pyrite nodules. Black phyllites and meta-cherts in the “Scisti sericitici” Formation are associated with Cu ores and with a small pyrite-molybdenite mineralization. These rocks are made of variable amounts of quartz, “chlorite”, illite/muscovite, pyrite ± calcite ± albite plus accessory amounts of baryte, apatite, sulfides and sulfosalts. In addition, they contain abundant carbonaceous matter (2-12 wt% total organic carbon). Whole-rock analyses by ICP-MS reveal a marked enrichment of Cd, Ag, Zn, Sb, Cu, Mo, V, Pb, and Tl with respect to the average marine shale and to the more typical shales of the “Scaglia toscana” Fm. The distribution of these elements in the studied samples is compatible with a strongly anoxic and euxinic depositional environment. The hyper-enrichment of Cd, Ag, Zn, Sb and Cu strongly suggests that besides from seawater these elements were extracted from additional sources, most likely hydrothermal vents.
{"title":"Late Cretaceous black shales from the Tuscan Sedimentary Succession (northern Tuscany, Italy): geochemistry and ore mineralogy","authors":"M. D’Orazio, C. Biagioni, D. Mantovani","doi":"10.3301/ijg.2020.30","DOIUrl":"https://doi.org/10.3301/ijg.2020.30","url":null,"abstract":"We report on the first geochemical and mineralogical study of the Late Cretaceous black shales and black phyllites occurring within the basal portion of the “Scaglia toscana” and “Scisti sericitici” formations, respectively (Northern Apennines, northern Tuscany, Italy). The black shales occurring within the “Scaglia toscana” Formation are interbedded with red and greenish shales and form cm-thick layers; in some localities they are characterized by the occurrence of cm- sized pyrite nodules. Black phyllites and meta-cherts in the “Scisti sericitici” Formation are associated with Cu ores and with a small pyrite-molybdenite mineralization. These rocks are made of variable amounts of quartz, “chlorite”, illite/muscovite, pyrite ± calcite ± albite plus accessory amounts of baryte, apatite, sulfides and sulfosalts. In addition, they contain abundant carbonaceous matter (2-12 wt% total organic carbon). Whole-rock analyses by ICP-MS reveal a marked enrichment of Cd, Ag, Zn, Sb, Cu, Mo, V, Pb, and Tl with respect to the average marine shale and to the more typical shales of the “Scaglia toscana” Fm. The distribution of these elements in the studied samples is compatible with a strongly anoxic and euxinic depositional environment. The hyper-enrichment of Cd, Ag, Zn, Sb and Cu strongly suggests that besides from seawater these elements were extracted from additional sources, most likely hydrothermal vents.","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77294088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Milli, S. Critelli, Emanuele Amicone, G. Campilongo, F. Muto, V. Tripodi, D. Tentori, F. Perri
Clastic wedges deposited in deep-marine turbidite systems along the circum-Mediterranean region represent key tectonic elements that record the structural growing of the Apennine orogenic belt over the Adria margin. One of these clastic wedges is represented by the Agnone Flysch turbidite succession deposited in the Lagonegro-Molise foredeep basin in the early Messinian, for which the depositional facies and the related processes, as well as the sandstone and mudstone composition are poorly known. A combined sedimentology and sedimentary petrology study has been conducted on this turbidite succession that provides new insight to define the basin architecture and the provenance of the Agnone Flysch during late Miocene. Facies analysis suggests that this turbidite succession is constituted by depositional lobes that were emplaced in a sector of the basin showing a variable morphological confinement with frontal and lateral slope on which turbidite deposits onlapped. Consequently, this topographic context controlled the lateral and vertical distribution of turbidite facies, which record the effects of erosive processes, as well as impact, rebound and reflection processes, in turn related to the flow deceleration induced by structurally-controlled basin confinement. Detailed sandstones compositional analysis indicates a complex unroofing history that reflects structural changes in the source rock units and depositional basin physiography. By combining the sandstone composition with information deduced from the X-ray diffraction (XRD) patterns after thermo-chemical treatments (heating and ethylene glycol treatments), it was possible to explain and predict the sedimentary evolution and geological processes affecting fine grained sediments and, thus, the relationship developed between source area and sedimentary basin. In particular, clay minerals data show that Agnone Flysch experienced an early diagenetic condition as showed by the occurrence of the I/S R0 and I/S R1 on the XRD pattern of the glycolated specimens. The sandstone composition (mainly quartzofeldspathic) shows an increase in the metamorphic rock fragments and a decrease of sedimentary lithics up-section. This compositional trend records, together with the paleocurrents data, a derivation of this material from a mountain range located in the Tyrrhenian sector and from the Calabrian arc terranes.
{"title":"Facies, composition and provenance of the Agnone Flysch in the context of the early Messinian evolution of the southern Apennine foredeep (Molise, Italy)","authors":"S. Milli, S. Critelli, Emanuele Amicone, G. Campilongo, F. Muto, V. Tripodi, D. Tentori, F. Perri","doi":"10.3301/IJG.2021.01","DOIUrl":"https://doi.org/10.3301/IJG.2021.01","url":null,"abstract":"Clastic wedges deposited in deep-marine turbidite systems along the circum-Mediterranean region represent key tectonic elements that record the structural growing of the Apennine orogenic belt over the Adria margin. One of these clastic wedges is represented by the Agnone Flysch turbidite succession deposited in the Lagonegro-Molise foredeep basin in the early Messinian, for which the depositional facies and the related processes, as well as the sandstone and mudstone composition are poorly known. A combined sedimentology and sedimentary petrology study has been conducted on this turbidite succession that provides new insight to define the basin architecture and the provenance of the Agnone Flysch during late Miocene. Facies analysis suggests that this turbidite succession is constituted by depositional lobes that were emplaced in a sector of the basin showing a variable morphological confinement with frontal and lateral slope on which turbidite deposits onlapped. Consequently, this topographic context controlled the lateral and vertical distribution of turbidite facies, which record the effects of erosive processes, as well as impact, rebound and reflection processes, in turn related to the flow deceleration induced by structurally-controlled basin confinement. Detailed sandstones compositional analysis indicates a complex unroofing history that reflects structural changes in the source rock units and depositional basin physiography. By combining the sandstone composition with information deduced from the X-ray diffraction (XRD) patterns after thermo-chemical treatments (heating and ethylene glycol treatments), it was possible to explain and predict the sedimentary evolution and geological processes affecting fine grained sediments and, thus, the relationship developed between source area and sedimentary basin. In particular, clay minerals data show that Agnone Flysch experienced an early diagenetic condition as showed by the occurrence of the I/S R0 and I/S R1 on the XRD pattern of the glycolated specimens. The sandstone composition (mainly quartzofeldspathic) shows an increase in the metamorphic rock fragments and a decrease of sedimentary lithics up-section. This compositional trend records, together with the paleocurrents data, a derivation of this material from a mountain range located in the Tyrrhenian sector and from the Calabrian arc terranes.","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85679063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hybrid event bed distribution in a mixed siliciclastic-calcareous turbidite succession: a cross-current perspective from the Bordighera Sandstone, Ligurian Alps, NW Italy","authors":"P. Mueller, Marco Patacci, A. Giulio","doi":"10.3301/ijg.2020.32","DOIUrl":"https://doi.org/10.3301/ijg.2020.32","url":null,"abstract":"","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77263347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Vigni, K. Daskalopoulou, S. Calabrese, F. Parello, W. D’Alessandro
The complex geology of Greece includes two important parallel running ophiolitic belts. The Othrys Massif in central Greece belongs to the westernmost of them. In the current study, 33 water samples from cold hyperalkaline and hypothermal (T < 40°C) alkaline springs and 30 gas samples (either dissolved or free) were collected at 17 different sites in and around this wide ophiolite outcrop, aiming to determine the origin of fluids and evidence gas-water-rock interaction processes taking place in the area. Water samples were analysed for their chemical (major ions and trace elements) and isotope (δ18O-H2O, δ2H-H2O) composition. They can be subdivided into alkaline (pH 11 and Ca-OH composition). Trace elements generally showed very low concentrations and mostly inversely correlated with pH. Gases were analysed for their chemical (He, Ne, Ar, H2, O2, N2, CH4, C2H6, CO2 and H2S) and isotope (δ13C-CH4, δ2H-CH4, δ13C-CO2) composition. Samples from alkaline waters were mainly dominated by CH4 (from 128,000 to 915,000 μmol/mol), while hyperalkaline waters showed a N2-rich composition (from 727,000 to 977,000 μmol/mol). Methane had a wide range of isotope compositions (δ13C-CH4 from -74.5 to -14.5 ‰ and δ2H-CH4 from -343 to -62 ‰). Alkaline waters present the most negative isotope values for CH4, evidencing a biogenic (both thermogenic and microbial) origin. Many of the hyperalkaline waters had CH4 isotope values compatible with an abiogenic origin through serpentinization processes but occasionaly very negative values were recorded, indicating sometimes a clear biogenic contribution. Finally, few samples both from alkaline and hyperalkaline waters showed some evidence of secondary oxidation processes.
{"title":"Geochemical characterisation of the alkaline and hyperalkaline groundwater in the Othrys Ophiolite Massif, central Greece","authors":"L. Vigni, K. Daskalopoulou, S. Calabrese, F. Parello, W. D’Alessandro","doi":"10.3301/ijg.2020.20","DOIUrl":"https://doi.org/10.3301/ijg.2020.20","url":null,"abstract":"The complex geology of Greece includes two important parallel running ophiolitic belts. The Othrys Massif in central Greece belongs to the westernmost of them. In the current study, 33 water samples from cold hyperalkaline and hypothermal (T < 40°C) alkaline springs and 30 gas samples (either dissolved or free) were collected at 17 different sites in and around this wide ophiolite outcrop, aiming to determine the origin of fluids and evidence gas-water-rock interaction processes taking place in the area. Water samples were analysed for their chemical (major ions and trace elements) and isotope (δ18O-H2O, δ2H-H2O) composition. They can be subdivided into alkaline (pH 11 and Ca-OH composition). Trace elements generally showed very low concentrations and mostly inversely correlated with pH. Gases were analysed for their chemical (He, Ne, Ar, H2, O2, N2, CH4, C2H6, CO2 and H2S) and isotope (δ13C-CH4, δ2H-CH4, δ13C-CO2) composition. Samples from alkaline waters were mainly dominated by CH4 (from 128,000 to 915,000 μmol/mol), while hyperalkaline waters showed a N2-rich composition (from 727,000 to 977,000 μmol/mol). Methane had a wide range of isotope compositions (δ13C-CH4 from -74.5 to -14.5 ‰ and δ2H-CH4 from -343 to -62 ‰). Alkaline waters present the most negative isotope values for CH4, evidencing a biogenic (both thermogenic and microbial) origin. Many of the hyperalkaline waters had CH4 isotope values compatible with an abiogenic origin through serpentinization processes but occasionaly very negative values were recorded, indicating sometimes a clear biogenic contribution. Finally, few samples both from alkaline and hyperalkaline waters showed some evidence of secondary oxidation processes.","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75404684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Muçi, K. Skrame, Oltion Fociro, M. Mancini, I. Gaudiosi, M. Simionato
The study analyses the effects of two chemical agents - cement and fly ash - in changing the swelling potential and the strength parameters of an expansive clay soil collected from Currila area in the city of Durres, Albania. The results obtained show a significant reduction of the plasticity index, with the addition of 3% cement and the combination of 3.5% cement with 8% fly-ash for a curing period for 1, 24 and 48 hours. The agglomerations formed after the reaction with the additives, changed the particle size and plastic behaviour of the soil from clay to silt of high plasticity, and the compaction curve shifted from a bell-shaped one into a flat shape. The swelling potential decreased to zero, as observed for curing periods of 7 and 28 days, reducing the swelling pressure from 70, to 30, to 0 kPa and the change in volume due to settlement to a mere 0.15mm for a 20mm initial height. The unconfined compressive strength increased by a factor of 1.52 and 2.22 with the addition of 3.5C-8FA for a 7-day and 28-day curing period, respectively.
{"title":"Effect of cement and fly-ash on the geotechnical properties of expansive clay soils","authors":"R. Muçi, K. Skrame, Oltion Fociro, M. Mancini, I. Gaudiosi, M. Simionato","doi":"10.3301/ijg.2020.21","DOIUrl":"https://doi.org/10.3301/ijg.2020.21","url":null,"abstract":"The study analyses the effects of two chemical agents - cement and fly ash - in changing the swelling potential and the strength parameters of an expansive clay soil collected from Currila area in the city of Durres, Albania. The results obtained show a significant reduction of the plasticity index, with the addition of 3% cement and the combination of 3.5% cement with 8% fly-ash for a curing period for 1, 24 and 48 hours. The agglomerations formed after the reaction with the additives, changed the particle size and plastic behaviour of the soil from clay to silt of high plasticity, and the compaction curve shifted from a bell-shaped one into a flat shape. The swelling potential decreased to zero, as observed for curing periods of 7 and 28 days, reducing the swelling pressure from 70, to 30, to 0 kPa and the change in volume due to settlement to a mere 0.15mm for a 20mm initial height. The unconfined compressive strength increased by a factor of 1.52 and 2.22 with the addition of 3.5C-8FA for a 7-day and 28-day curing period, respectively.","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84370647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Lazzaroni, M. Ceccatelli, L. Rossato, B. Nisi, S. Venturi, R. Fanti, F. Tassi, O. Vaselli
A severe boron pollution has been recognized in the shallow aquifer of Isola di Castelluccio (central-eastern Tuscany, Italy) since 2009. Previous investigations showed that the high boron concentrations (up to 57 mg L-1) were related to an anthropogenic source. It was likely due to current and/or past industrial and artisanal activities, which were using B-compounds during their productive cycles. However, a univocal source of boron has so far not been recognized. In this work, we present and discuss new geochemical and isotopic data related to an extensive campaign (June 2016) carried out in 33 domestic well and piezometer waters. In addition, the results from a three-weekly to monthly monitoring survey (from August 2014 to December 2019) on selected waters were used to recognize signals in response to dry and wet periods or related to the presence of the recently installed hydraulic barrier. To verify the efficiency of the hydraulic barrier a numerical model of the shallow aquifer was performed by using the MODFLOW computer program. This study has allowed to identify where the source of contamination is likely located. This implies that specific investigations can now be carried out to definitively remove the anthropogenic source of boron.
自2009年以来，在意大利托斯卡纳中东部的Isola di Castelluccio浅层含水层中发现了严重的硼污染。先前的研究表明，高硼浓度(高达57 mg L-1)与人为来源有关。这可能是由于当前和/或过去的工业和手工活动在其生产周期中使用了b -化合物。然而，到目前为止，还没有发现硼的单一来源。在这项工作中，我们介绍并讨论了新的地球化学和同位素数据，这些数据与一项广泛的运动(2016年6月)有关，该运动在33口国内井和气压计水域进行。此外，对选定水域(2014年8月至2019年12月)进行的每周一次或每月一次的监测调查结果用于识别干湿期或与最近安装的水力屏障存在相关的信号。为了验证水力屏障的有效性，利用MODFLOW计算机程序对浅层含水层进行了数值模拟。这项研究已经确定了污染源可能的位置。这意味着现在可以进行具体的研究，以明确地消除硼的人为来源。
{"title":"Boron pollution in the shallow groundwater system from Isola di Castelluccio (central-eastern, Tuscany): evidences from a geochemical survey and new remediation perspectives from a recently-installed hydraulic barrier and hydrogeological modelling","authors":"M. Lazzaroni, M. Ceccatelli, L. Rossato, B. Nisi, S. Venturi, R. Fanti, F. Tassi, O. Vaselli","doi":"10.3301/ijg.2020.23","DOIUrl":"https://doi.org/10.3301/ijg.2020.23","url":null,"abstract":"A severe boron pollution has been recognized in the shallow aquifer of Isola di Castelluccio (central-eastern Tuscany, Italy) since 2009. Previous investigations showed that the high boron concentrations (up to 57 mg L-1) were related to an anthropogenic source. It was likely due to current and/or past industrial and artisanal activities, which were using B-compounds during their productive cycles. However, a univocal source of boron has so far not been recognized. In this work, we present and discuss new geochemical and isotopic data related to an extensive campaign (June 2016) carried out in 33 domestic well and piezometer waters. In addition, the results from a three-weekly to monthly monitoring survey (from August 2014 to December 2019) on selected waters were used to recognize signals in response to dry and wet periods or related to the presence of the recently installed hydraulic barrier. To verify the efficiency of the hydraulic barrier a numerical model of the shallow aquifer was performed by using the MODFLOW computer program. This study has allowed to identify where the source of contamination is likely located. This implies that specific investigations can now be carried out to definitively remove the anthropogenic source of boron.","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86888652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Rouwet, G. Tamburello, G. Chiodini, G. Pecoraino, M. Procesi, T. Ricci, S. Venturi, A. Santi, J. Cabassi, O. Vaselli, F. Tassi, A. Costa
With this study a nine-year hiatus (May 2010-April 2019) in the quantification of the CO2 content of Lago Albano by our working group has been resolved through the acquisition and analysis from two new field campaigns. Based on a CO2 budget analysis the dynamics of CO2 degassing throughout the past thirty years (1989-2019) is detailed and quantified. The decreasing CO2 content (expressed as dissolved inorganic carbon, DIC) in the lake, since the co-seismic CO2 input during the 1989-1990 seismic swarm beneath Colli Albani volcano, was accelerated at lake bottom layers (-140 m to bottom, near -160 m) in the 4-5 years after the swarm, continued afterwards at lower depths (-125 to -95 m), and seems to have reached steady-state conditions during recent years. The peculiar lake basin morphology has control on the degassing dynamics. The low chemical gradients detected during the April 2019 survey have induced near-zero degassing conditions, and arguably stopped the gas-self lifting process: Lago Albano might not become CO2-free in the future. This finding has implications for gas hazard when the next seismic swarm will hit the area. The updated degassing model also takes into account the lake level drop, and hence the volume decrease of Lago Albano, caused by excessive well pumping for anthropic purposes. This volume decrease appears to have a destabilizing effect on the degassing dynamics, which renders Lago Albano’s gas release less predictable in the future. Enhanced gas surveys (high-frequency and fine-scale spatial measurements) are needed to shed light on how Lago Albano degasses in this quiescent stage during the Anthropocene. A submersible infra-red detector to directly measure in-lake dissolved CO2 concentrations, applied satisfactorily during this study, is an adapted instrument to do so.
{"title":"New insights into the degassing dynamics of Lago Albano (Colli Albani volcano, Rome, Italy) during the last three decades (1989-2019)","authors":"D. Rouwet, G. Tamburello, G. Chiodini, G. Pecoraino, M. Procesi, T. Ricci, S. Venturi, A. Santi, J. Cabassi, O. Vaselli, F. Tassi, A. Costa","doi":"10.3301/ijg.2020.19","DOIUrl":"https://doi.org/10.3301/ijg.2020.19","url":null,"abstract":"With this study a nine-year hiatus (May 2010-April 2019) in the quantification of the CO2 content of Lago Albano by our working group has been resolved through the acquisition and analysis from two new field campaigns. Based on a CO2 budget analysis the dynamics of CO2 degassing throughout the past thirty years (1989-2019) is detailed and quantified. The decreasing CO2 content (expressed as dissolved inorganic carbon, DIC) in the lake, since the co-seismic CO2 input during the 1989-1990 seismic swarm beneath Colli Albani volcano, was accelerated at lake bottom layers (-140 m to bottom, near -160 m) in the 4-5 years after the swarm, continued afterwards at lower depths (-125 to -95 m), and seems to have reached steady-state conditions during recent years. The peculiar lake basin morphology has control on the degassing dynamics. The low chemical gradients detected during the April 2019 survey have induced near-zero degassing conditions, and arguably stopped the gas-self lifting process: Lago Albano might not become CO2-free in the future. This finding has implications for gas hazard when the next seismic swarm will hit the area. The updated degassing model also takes into account the lake level drop, and hence the volume decrease of Lago Albano, caused by excessive well pumping for anthropic purposes. This volume decrease appears to have a destabilizing effect on the degassing dynamics, which renders Lago Albano’s gas release less predictable in the future. Enhanced gas surveys (high-frequency and fine-scale spatial measurements) are needed to shed light on how Lago Albano degasses in this quiescent stage during the Anthropocene. A submersible infra-red detector to directly measure in-lake dissolved CO2 concentrations, applied satisfactorily during this study, is an adapted instrument to do so.","PeriodicalId":55341,"journal":{"name":"Bollettino Della Societa Geologica Italiana","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84864034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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