Pub Date : 2023-09-22DOI: 10.3390/geosciences13100288
Florin Pavel, George Nica
This study is focused on evaluating ground motion durations of Vrancea intermediate-depth earthquakes in Romania, in the context of future updates to the Romanian seismic design code P100-1/2013. The ground motion database compiled for this study consists of about 200 ground motions recorded during five moderate and large Vrancea intermediate-depth earthquakes that occurred in the period of 1977–2004 and had moment magnitudes of MW ≥ 6.0. Two empirical models were derived in this study for the significant ground motion duration considering two time intervals (5–75% and 5–95%) for the accumulation of the Arias Intensity IA. An analysis of the data shows that the mean ratio between D5-95 and D5-75 is about 2.8. Moreover, the regression also shows that the largest share of variability is due to the within-event component (site term). Among the regression coefficients, the hypocentral distance and the soil conditions appear to have a larger impact on the ground motion duration compared to the earthquake magnitude. It was also observed that the median ground motion durations predicted using the empirical model proposed in this study were much smaller than the ones from the proposed Eurocode 8 draft for the same magnitude range. Finally, geographic trends related to the distribution of residuals were also evaluated using the data from the three earthquakes with the largest number of available ground motion recordings.
{"title":"Ground Motion Duration Patterns for Vrancea (Romania) Intermediate-Depth Earthquakes","authors":"Florin Pavel, George Nica","doi":"10.3390/geosciences13100288","DOIUrl":"https://doi.org/10.3390/geosciences13100288","url":null,"abstract":"This study is focused on evaluating ground motion durations of Vrancea intermediate-depth earthquakes in Romania, in the context of future updates to the Romanian seismic design code P100-1/2013. The ground motion database compiled for this study consists of about 200 ground motions recorded during five moderate and large Vrancea intermediate-depth earthquakes that occurred in the period of 1977–2004 and had moment magnitudes of MW ≥ 6.0. Two empirical models were derived in this study for the significant ground motion duration considering two time intervals (5–75% and 5–95%) for the accumulation of the Arias Intensity IA. An analysis of the data shows that the mean ratio between D5-95 and D5-75 is about 2.8. Moreover, the regression also shows that the largest share of variability is due to the within-event component (site term). Among the regression coefficients, the hypocentral distance and the soil conditions appear to have a larger impact on the ground motion duration compared to the earthquake magnitude. It was also observed that the median ground motion durations predicted using the empirical model proposed in this study were much smaller than the ones from the proposed Eurocode 8 draft for the same magnitude range. Finally, geographic trends related to the distribution of residuals were also evaluated using the data from the three earthquakes with the largest number of available ground motion recordings.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136095014","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}
Pub Date : 2023-09-22DOI: 10.3390/geosciences13100287
Francisco Grajales-Saavedra, Alexis Mojica, Carlos Ho, Krysna Samudio, George Mejía, Saddy Li, Larisa Almengor, Roberto Miranda, Melisabel Muñoz
The City of David constitutes one of the most important commercial centers of the Republic of Panama. However, it is located on a coastal plane, close to an area with high seismic activity and has been affected by significant earthquakes (18 July 1934, Mw = 7.4 and 12 March 1962, Mw = 6.7). The goal of this study is to estimate the seismic effects and to classify the soil in the City of David. The experimental work entailed the measurement of environmental noise for H/V spectral ratio (HVSR) analyzed at 22 stations. A series of microtremor refraction studies (ReMi) at six stations distributed from north to south of the city was also performed. The stations were distributed around urban areas of the city, which are characterized by the presence of water supply, sewerage, buildings, roads, etc. The spectral analysis of environmental noise allowed the generation of three different types of maps: First, predominant frequency maps (f0) with zones composed mainly of rigid and semi-rigid soils in the southern end of the city and rigid soils in the central and northern regions. Secondly, maximum H/V amplitude maps (A0) which evidence a low range of HVSR amplitude in the city, ranging from 1.1 to 3.8. Finally, liquefaction vulnerability (Kg) maps, with values less than 2 Hz−1, representative of a low liquefaction risk. Soil classification using ReMi and calculation of the corresponding Vs30 reveal type D soils, which correlate well with results obtained using HVSR analyses. A comparison between HVSR and ReMi shows that HVSR curves that exhibit clear peaks tend to be related to ReMi stations that presented relatively large shear-wave velocity contrasts at some depth. The results from this research are intended to aid the decision-making process related to the future development of the city, as well as government level maintenance and mitigation plans.
{"title":"Horizontal-to-Vertical Spectral Ratios and Refraction Microtremor Analyses for Seismic Site Effects and Soil Classification in the City of David, Western Panama","authors":"Francisco Grajales-Saavedra, Alexis Mojica, Carlos Ho, Krysna Samudio, George Mejía, Saddy Li, Larisa Almengor, Roberto Miranda, Melisabel Muñoz","doi":"10.3390/geosciences13100287","DOIUrl":"https://doi.org/10.3390/geosciences13100287","url":null,"abstract":"The City of David constitutes one of the most important commercial centers of the Republic of Panama. However, it is located on a coastal plane, close to an area with high seismic activity and has been affected by significant earthquakes (18 July 1934, Mw = 7.4 and 12 March 1962, Mw = 6.7). The goal of this study is to estimate the seismic effects and to classify the soil in the City of David. The experimental work entailed the measurement of environmental noise for H/V spectral ratio (HVSR) analyzed at 22 stations. A series of microtremor refraction studies (ReMi) at six stations distributed from north to south of the city was also performed. The stations were distributed around urban areas of the city, which are characterized by the presence of water supply, sewerage, buildings, roads, etc. The spectral analysis of environmental noise allowed the generation of three different types of maps: First, predominant frequency maps (f0) with zones composed mainly of rigid and semi-rigid soils in the southern end of the city and rigid soils in the central and northern regions. Secondly, maximum H/V amplitude maps (A0) which evidence a low range of HVSR amplitude in the city, ranging from 1.1 to 3.8. Finally, liquefaction vulnerability (Kg) maps, with values less than 2 Hz−1, representative of a low liquefaction risk. Soil classification using ReMi and calculation of the corresponding Vs30 reveal type D soils, which correlate well with results obtained using HVSR analyses. A comparison between HVSR and ReMi shows that HVSR curves that exhibit clear peaks tend to be related to ReMi stations that presented relatively large shear-wave velocity contrasts at some depth. The results from this research are intended to aid the decision-making process related to the future development of the city, as well as government level maintenance and mitigation plans.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136095015","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 investigation of deformations in Quaternary deposits holds primary importance in understanding recent geological history and natural hazards in highly populated areas, such as the Po Plain. While civil excavations and trenches possess the potential to be pivotal in identifying and characterizing these deformations, they often remain underused due to the stringent regulation framework and timetables governing civil construction works. In this study, we demonstrate how digital photogrammetry and digital outcrop modelling (DOM) are useful techniques for obtaining a permanent digital representation of a trench situated in Castelletto Ticino (Po Plain–Southern Alps transition). This trench exhibits Holocene deformational structures: (i) an overall tilting of sedimentary deposits towards the SW; (ii) folds with a NE–SW trend; (iii) slumping and other soft-sediment deformations structures; and (iv) reverse faults with NE–SW and NW–SE directions. Using radiocarbon and archeological dating, we are able to confidently constrain the age of these deformations to between 8760 and 400 years BC, suggesting recent tectonic activity related to buried thrust faults.
{"title":"Holocene Deformations at the Po Plain–Southern Alps Transition (Lake Maggiore, Italy): Inferences on Glacially vs. Tectonic-Induced Origin","authors":"Niccolò Menegoni, Matteo Maino, Giovanni Toscani, Lucia Isabella Mordeglia, Gianfranco Valle, Cesare Perotti","doi":"10.3390/geosciences13090286","DOIUrl":"https://doi.org/10.3390/geosciences13090286","url":null,"abstract":"The investigation of deformations in Quaternary deposits holds primary importance in understanding recent geological history and natural hazards in highly populated areas, such as the Po Plain. While civil excavations and trenches possess the potential to be pivotal in identifying and characterizing these deformations, they often remain underused due to the stringent regulation framework and timetables governing civil construction works. In this study, we demonstrate how digital photogrammetry and digital outcrop modelling (DOM) are useful techniques for obtaining a permanent digital representation of a trench situated in Castelletto Ticino (Po Plain–Southern Alps transition). This trench exhibits Holocene deformational structures: (i) an overall tilting of sedimentary deposits towards the SW; (ii) folds with a NE–SW trend; (iii) slumping and other soft-sediment deformations structures; and (iv) reverse faults with NE–SW and NW–SE directions. Using radiocarbon and archeological dating, we are able to confidently constrain the age of these deformations to between 8760 and 400 years BC, suggesting recent tectonic activity related to buried thrust faults.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136128883","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}
Pub Date : 2023-09-21DOI: 10.3390/geosciences13090285
Ioanna Triantafyllou, Gerassimos A. Papadopoulos
The seismicity in the Ionian Sea region is very high. In the historical period, many earthquakes have been reported mainly since the 16th century. In this research, we investigated the historical seismicity in the Ionian Sea, emphasizing earthquakes that have been damaging or strongly felt on Zakynthos (Zante) island. A variety of information sources, which have not been utilized so far and covering the time period from AD 1513 to 1900, were collected and examined. The sources utilized included archives, short chronicles, marginal notes, diaries and official scientific bulletins. This research reveals new information for earthquakes that have remained unknown or little-known in the seismological tradition so far. In addition, new information was found for important and already known earthquake episodes, such as the 1886 large and extensively damaging earthquake in the southwestern Peloponnese and the prolonged and destructive earthquake sequence of 1893 on Zakynthos Island, as well as for the little-known damaging earthquake of 1898. Our research adds new information about the earthquake effects in both the built and natural environments and helps also to correct earthquake dates and to identify spurious events.
{"title":"Earthquakes in the Ionian Sea, Greece, Documented from Little-Known Historical Sources: AD 1513–1900","authors":"Ioanna Triantafyllou, Gerassimos A. Papadopoulos","doi":"10.3390/geosciences13090285","DOIUrl":"https://doi.org/10.3390/geosciences13090285","url":null,"abstract":"The seismicity in the Ionian Sea region is very high. In the historical period, many earthquakes have been reported mainly since the 16th century. In this research, we investigated the historical seismicity in the Ionian Sea, emphasizing earthquakes that have been damaging or strongly felt on Zakynthos (Zante) island. A variety of information sources, which have not been utilized so far and covering the time period from AD 1513 to 1900, were collected and examined. The sources utilized included archives, short chronicles, marginal notes, diaries and official scientific bulletins. This research reveals new information for earthquakes that have remained unknown or little-known in the seismological tradition so far. In addition, new information was found for important and already known earthquake episodes, such as the 1886 large and extensively damaging earthquake in the southwestern Peloponnese and the prolonged and destructive earthquake sequence of 1893 on Zakynthos Island, as well as for the little-known damaging earthquake of 1898. Our research adds new information about the earthquake effects in both the built and natural environments and helps also to correct earthquake dates and to identify spurious events.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136152971","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}
Pub Date : 2023-09-20DOI: 10.3390/geosciences13090284
Guiomar Calvo, Beatriz Carrasquer-Álvarez, Javier Martínez-Aznar
Salt harvesting through natural solar evaporation of salt brines is a practice notably abundant in the Iberian Peninsula. Such activity has been relevant for human consumption, food preservation, livestock feed, and various industries throughout history. The objective of this research is to analyze the productive history and conservation state of the salt evaporation ponds located in Naval and Peralta de la Sal (Huesca, Spain), as well as their didactic potential. These saltworks are associated with clay and gypsum levels from the Upper Triassic (Keuper). The earliest written records of salt production in the area date back to the 10th century, but they were exploited as early as the Bronze Age. Remains of most of the ponds and some buildings are still preserved and are easily accessed, which makes them very interesting from an educational perspective. Both on-site and off-site activities can be carried out to analyze their historical and current significance through modeling and argumentation practices. This can lead to a better understanding of how geology relates to everyday life and facilitate the development of positive attitudes among students towards geoheritage while raising awareness about its preservation and preventing its degradation.
在伊比利亚半岛，通过自然的太阳能蒸发盐盐是一种非常丰富的做法。这种活动在历史上一直与人类消费、食品保存、牲畜饲料和各种工业有关。本研究的目的是分析位于Naval和Peralta de la Sal(西班牙韦斯卡)的盐蒸发池的生产历史和保护状况，以及它们的教学潜力。这些盐场与上三叠世(Keuper)的粘土和石膏水平有关。该地区最早的盐生产文字记录可以追溯到10世纪，但早在青铜时代就开始开采了。大部分池塘和一些建筑的遗迹仍然保存下来，很容易进入，从教育的角度来看，这使得它们非常有趣。现场和非现场活动都可以通过建模和论证实践来分析其历史和当前的意义。这可以使学生更好地了解地质学与日常生活的关系，并促进学生对地质遗产的积极态度，同时提高对地质遗产保护和防止其退化的认识。
{"title":"Salt Production and the Geoheritage of the Huesca Province (Spain): Context, History, and Potential as an Educational Resource","authors":"Guiomar Calvo, Beatriz Carrasquer-Álvarez, Javier Martínez-Aznar","doi":"10.3390/geosciences13090284","DOIUrl":"https://doi.org/10.3390/geosciences13090284","url":null,"abstract":"Salt harvesting through natural solar evaporation of salt brines is a practice notably abundant in the Iberian Peninsula. Such activity has been relevant for human consumption, food preservation, livestock feed, and various industries throughout history. The objective of this research is to analyze the productive history and conservation state of the salt evaporation ponds located in Naval and Peralta de la Sal (Huesca, Spain), as well as their didactic potential. These saltworks are associated with clay and gypsum levels from the Upper Triassic (Keuper). The earliest written records of salt production in the area date back to the 10th century, but they were exploited as early as the Bronze Age. Remains of most of the ponds and some buildings are still preserved and are easily accessed, which makes them very interesting from an educational perspective. Both on-site and off-site activities can be carried out to analyze their historical and current significance through modeling and argumentation practices. This can lead to a better understanding of how geology relates to everyday life and facilitate the development of positive attitudes among students towards geoheritage while raising awareness about its preservation and preventing its degradation.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136306534","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}
Pub Date : 2023-09-20DOI: 10.3390/geosciences13090283
Abdallah Atef, Adel A. Surour, Ahmed A. Madani, Mokhles K. Azer
Since Antiquity, sustainable resources of gold and copper have been mined at two prominent prospects in the north Eastern Desert of Egypt, namely the south Gabel Um Monqul (SGUM) and Gabal Al Kharaza (GKZ). Mineralization is hosted by Neoproterozoic shield rocks represented by dacite and monzo- to syenogranite at the SGUM prospect whereas they are diorite, granodiorite, and quartz feldspar porphyry at the GKZ prospect. These hosts have been emplaced in an island arc environment from calc-alkaline magmas with a peraluminous to metaluminous signature. They are hydrothermally altered including albitization, sericitization, silicification, epidotization, and chloritization. The Au and Cu mineralizations are confined to shear zones that lately filled with auriferous quartz veins adjacent to mineralized alteration zones. In the GKZ prospect, the old trenches trend mainly in a NW–SE direction whereas it is NE–SW and NW–SE in the SGUM prospect. Evidence of shearing ranges from megascopic conjugate fractures and shear planes in the outcrops to microscopic sheared and crumbled Au-Cu ore assemblages dominated by Fe-Cu sulfides, specularite, and barite. Microscopic investigation suggests that the formation of specularite is due to the shearing of early existing magnetite. The ore textures and paragenetic sequence indicate that pyrite in the alteration zones is oxidized, leading to the liberation of gold up to 3.3 g/t. The formulae of the analyzed electrum lie in the range Au74.5-76.8 Ag22.2-24.5. Integration of the field, geochemistry, and mineral chemistry data, combined with the gold fire assay data prove the presence of sustainable amounts of disseminated Au and Cu, not only in the mineralized quartz veins, but also in the alteration zones. Data materialized in our paper show similarities in the style of mineralization at the SGUM and the GKZ prospects with iron oxide-copper-gold (IOCG) deposits elsewhere in the Arabian-Nubian Shield (ANS) and other world examples.
自古以来，在埃及东北部沙漠的两个突出前景，即南Gabel Um Monqul (SGUM)和Gabal Al Kharaza (GKZ)，已经开采了可持续的金和铜资源。SGUM远景区以英安岩和二长-正长花岗岩为代表的新元古代盾构岩成矿，GKZ远景区以闪长岩、花岗闪长岩和石英长石斑岩为代表。这些寄主位于具有过铝质-铝质特征的钙碱性岩浆的岛弧环境中。它们被水热蚀变，包括钠长石化、绢云母化、硅化、绿帘石化和绿泥化。金矿化和铜矿化局限于矿化蚀变带附近的剪切带，这些剪切带最近充满了含金石英脉。在GKZ远景中，古海沟主要向北西-东南方向移动，而在SGUM远景中，古海沟主要向北东-西南和北西-东南方向移动。从露头的宏观共轭断裂和剪切面到微观剪切和破碎的以Fe-Cu硫化物、镜铁矿和重晶石为主的金铜矿组合，均存在剪切作用。显微研究表明镜铁矿的形成是由于早期存在的磁铁矿的剪切作用。矿石结构和共生序列表明，蚀变带黄铁矿被氧化，导致金析出量达3.3 g/t。所分析的电极的分子式在au74.5 ~ 76.8 ag22.2 ~ 24.5范围内。综合野外、地球化学和矿物化学资料，结合金火分析资料，证明在矿化石英脉中，以及蚀变带中均存在一定量的浸染金和铜。本文中物化的数据表明，SGUM和GKZ的矿化风格与阿拉伯-努比亚盾(ANS)其他地方的氧化铁-铜-金(IOCG)矿床和其他世界例子相似。
{"title":"Au-Cu Resources in Some Mines from Antiquity in the South Gabal Um Monqul and Gabal Al Kharaza Prospects, North Eastern Desert, Egypt","authors":"Abdallah Atef, Adel A. Surour, Ahmed A. Madani, Mokhles K. Azer","doi":"10.3390/geosciences13090283","DOIUrl":"https://doi.org/10.3390/geosciences13090283","url":null,"abstract":"Since Antiquity, sustainable resources of gold and copper have been mined at two prominent prospects in the north Eastern Desert of Egypt, namely the south Gabel Um Monqul (SGUM) and Gabal Al Kharaza (GKZ). Mineralization is hosted by Neoproterozoic shield rocks represented by dacite and monzo- to syenogranite at the SGUM prospect whereas they are diorite, granodiorite, and quartz feldspar porphyry at the GKZ prospect. These hosts have been emplaced in an island arc environment from calc-alkaline magmas with a peraluminous to metaluminous signature. They are hydrothermally altered including albitization, sericitization, silicification, epidotization, and chloritization. The Au and Cu mineralizations are confined to shear zones that lately filled with auriferous quartz veins adjacent to mineralized alteration zones. In the GKZ prospect, the old trenches trend mainly in a NW–SE direction whereas it is NE–SW and NW–SE in the SGUM prospect. Evidence of shearing ranges from megascopic conjugate fractures and shear planes in the outcrops to microscopic sheared and crumbled Au-Cu ore assemblages dominated by Fe-Cu sulfides, specularite, and barite. Microscopic investigation suggests that the formation of specularite is due to the shearing of early existing magnetite. The ore textures and paragenetic sequence indicate that pyrite in the alteration zones is oxidized, leading to the liberation of gold up to 3.3 g/t. The formulae of the analyzed electrum lie in the range Au74.5-76.8 Ag22.2-24.5. Integration of the field, geochemistry, and mineral chemistry data, combined with the gold fire assay data prove the presence of sustainable amounts of disseminated Au and Cu, not only in the mineralized quartz veins, but also in the alteration zones. Data materialized in our paper show similarities in the style of mineralization at the SGUM and the GKZ prospects with iron oxide-copper-gold (IOCG) deposits elsewhere in the Arabian-Nubian Shield (ANS) and other world examples.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136314308","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}
Pub Date : 2023-09-18DOI: 10.3390/geosciences13090281
Evgeny Chuvilin, Natalia Sokolova
This Special Issue of Geosciences is a collection of fifteen original research and overview papers on the response of permafrost and gas hydrates to ground warming caused by natural climate trends and industrial loads [...]
{"title":"Permafrost and Gas Hydrate Response to Ground Warming","authors":"Evgeny Chuvilin, Natalia Sokolova","doi":"10.3390/geosciences13090281","DOIUrl":"https://doi.org/10.3390/geosciences13090281","url":null,"abstract":"This Special Issue of Geosciences is a collection of fifteen original research and overview papers on the response of permafrost and gas hydrates to ground warming caused by natural climate trends and industrial loads [...]","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"214 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135201960","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}
Pub Date : 2023-09-18DOI: 10.3390/geosciences13090282
Érica T. Morais, Gabriel A. Barberes, Igor Viegas A. F. Souza, Fabiano G. Leal, Jarbas V. P. Guzzo, André L. D. Spigolon
This study applied the Pearson correlation coefficient and principal component analysis as tools for unsupervised qualitative petroleum system evaluation techniques. A total of 252 oil samples (32 features per sample) representative of two Brazilian sedimentary basins (Recôncavo and Potiguar) were used to classify them according to their respective degrees of maturation and origin. The large initial set of variables comprises data on δ13C composition, saturate, aromatic, polar compound fractions, and the techniques reduced biomarkers to the most important variables, maintaining the global pattern of variance. The results were efficient in discriminating different petroleum systems from lacustrine, marine, and mixing sources, as observed in the studied accumulations from the Lower Cretaceous sediments of the Recôncavo and Potiguar basins. The methodology proved to be very useful to vene better characterize the petroleum systems. This methodology can be applied to analyze a large amount of oil samples, using simple software and spending relatively less time.
{"title":"Pearson Correlation Coefficient Applied to Petroleum System Characterization: The Case Study of Potiguar and Reconcavo Basins, Brazil","authors":"Érica T. Morais, Gabriel A. Barberes, Igor Viegas A. F. Souza, Fabiano G. Leal, Jarbas V. P. Guzzo, André L. D. Spigolon","doi":"10.3390/geosciences13090282","DOIUrl":"https://doi.org/10.3390/geosciences13090282","url":null,"abstract":"This study applied the Pearson correlation coefficient and principal component analysis as tools for unsupervised qualitative petroleum system evaluation techniques. A total of 252 oil samples (32 features per sample) representative of two Brazilian sedimentary basins (Recôncavo and Potiguar) were used to classify them according to their respective degrees of maturation and origin. The large initial set of variables comprises data on δ13C composition, saturate, aromatic, polar compound fractions, and the techniques reduced biomarkers to the most important variables, maintaining the global pattern of variance. The results were efficient in discriminating different petroleum systems from lacustrine, marine, and mixing sources, as observed in the studied accumulations from the Lower Cretaceous sediments of the Recôncavo and Potiguar basins. The methodology proved to be very useful to vene better characterize the petroleum systems. This methodology can be applied to analyze a large amount of oil samples, using simple software and spending relatively less time.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135154180","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}
Pub Date : 2023-09-14DOI: 10.3390/geosciences13090279
Alexei B. Herman, Ksenia V. Domogatskaya
Three species belonging to the fern genus Ochotopteris E. Lebedev, including the new species O. lebedevii Herman et Domogatskaya, are revised, described and illustrated in this paper. The fossils come from Albian, Cenomanian, Turonian and Coniacian beds exposed at seven sites in North-Eastern Asia and Northern Alaska. These sites are located in the Cretaceous Arctic, with their palaeolatitudes ranging from 60° N to 80° N. The high endemism characteristic of the mid-Cretaceous Arctic flora is most probably due to adaptations in the globally distinctive Arctic conditions: the unique combination of temperatures, precipitation and the highly seasonal polar light regime. Being an endemic plant of the mid-Cretaceous Arctic, Ochotopteris ferns were adapted to a regional wet temperate to a wet warm temperate palaeoclimate accompanied by marked sunlight seasonality with a prolonged—up to several weeks—winter darkness and continuous summer daylight, also lasting for several weeks. The majority of the mid-Cretaceous Arctic plants were deciduous. Their predominant deciduousness was most probably due to the polar light seasonality: at the end of the growing season, some plants dropped their leaves or leafy shoots, whereas others—including Ochotopteris ferns—died back to rhizome systems.
本文对蕨类植物Ochotopteris E. Lebedev属的3个种(包括新种O. lebedevii Herman et Domogatskaya)进行了订正、描述和说明。这些化石来自东北亚和阿拉斯加北部七个地点的阿尔比亚、塞诺曼尼亚、土尔onian和Coniacian地层。这些地点位于白垩纪北极，古纬度从北纬60°到北纬80°。白垩纪中期北极植物群的高度地方性特征很可能是由于适应了全球独特的北极条件:温度、降水和高度季节性的极地光照制度的独特组合。作为白垩纪中期北极地区的一种特有植物，Ochotopteris蕨类植物适应于区域性的湿温带到湿暖温带的古气候，并具有明显的日照季节性，冬季的黑暗和夏季的连续日照也持续数周。大多数白垩纪中期的北极植物都是落叶植物。它们的主要落叶性很可能是由于极地的轻季节性:在生长季节结束时，一些植物的叶子或叶芽脱落，而其他植物——包括Ochotopteris蕨类植物——则死回到根茎系统。
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Pub Date : 2023-09-14DOI: 10.3390/geosciences13090278
Fedor N. Lisetskii, Zhanna A. Buryak, Olga A. Marinina, Pavel A. Ukrainskiy, Pavel V. Goleusov
The active development of the problems related to the assessment of the role of the pedosphere in global climate change involves the possibility of application of the quantitative determination of soil organic carbon (SOC) as one of the indicators of a climatic response. Here, the authors have summarized the results of their own research over many years (1985–2023), comprising more than 500 determinations of SOC within the area of the Chernozem zone, in the south of the East European Plain (Moldova and Bessarabia, southern Ukraine, southwestern Russia), in the context of regional climate differentiation using evaluations of climatic energy consumption for soil formation. The data were structured for each of the regions through the creation of series of agrogenic soil transformations (virgin land, modern-day ploughed land (<100 years), continually ploughed land (>100 years), fallow land of the modern era (n·10 years), and post-antique long-term fallow land). It has been established, by means of statistical treatment of the data, that the intraregional differentiation of the bioclimatic conditions is the key factor determining the SOC content in the top horizon of soils in the south of the East European Plain. The comparison of the SOC content within the five variants of land use demonstrated that all the regions under study differed, with statistical significance only found in a single type of ‘continually ploughed land’ (>100 years). This fact reflects the leading role of the duration of agrarian loads in agropedogenesis. If the steppe Chernozems even 145 years ago had a SOC content of up to 4%, then the Chernozems in the forest-steppe zone, which used to have habitats with a SOC content of 4–7%, occupied the largest areas, and have now lost 30–40% of the original values in the 0–50 cm layer. Besides the rates of the SOC degradation, which are known and are comprehensively evaluated in the present work, the phenomenon of progradation was established in certain situations, in particular arising during the rotation regime of land use (from ploughing to fallow fields, and vice versa), which stimulated effective mechanisms of reproduction of organic substances. Thus, in one of the ancient agricultural regions, where in antiquity the land was cultivated by such ancient Greek states as Tauric Chersonesos and the European Bosporos in Crimea, post-antique long-term fallow lands possess higher SOC contents than their virgin analogues. It is not justified to consider virgin lands as absolute references for the evaluation of the humus conditions since the analysis of agrogenic series of Chernozems has corroborated an essential role of the soil organo-mineral matrix in the formation of the carbon protection capacity.
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