C. Fonseca, J. G. Mendonça Filho, C. Lézin, F. Baudin, António Donizeti de Oliveira, Jaqueline Torres Souza, L. V. Duarte
Abstract The Toarcian Oceanic Anoxic Event (T-OAE) is marked by major palaeoenvironmental and palaeoceanographical changes on a global scale, associated with a severe disturbance of the global carbon cycle and organic-rich facies deposition. Here, a multiproxy approach (petrographic and geochemical techniques) was applied to the study of the organic content of the T-OAE of the Paris Basin, whose phytoplanktonic origin has been previously inferred by its geochemical signature. The top of the tenuicostatum Zone is characterized by palynomorphs and marine phytoplankton-derived amorphous organic matter (AOM), representing a proximal marine environment with emplacement of euxinic conditions at the top (total organic carbon/sulfur content and increase in AOM). At the base of the serpentinum Zone the proliferation of bacterial biomass begins, with phytoplankton playing a secondary role. This indicates the development of stagnant and restrictive conditions in a proximal environment, with water column stratification (neohop-13(18)-ene). The majority of the serpentinum Zone is dominated by bacterial biomass, suggesting a marine environment with bottom-water stagnation, possibly related to basin palaeogeomorphology and circulation patterns, with episodic euxinia. This therefore suggests that the T-OAE organic fraction is dominated by bacterial biomass, not phytoplankton, showing the importance of an integrated approach to the determination of the organic facies.
{"title":"Boosted microbial productivity during the Toarcian Oceanic Anoxic Event in the Paris Basin, France: new evidence from organic geochemistry and petrographic analysis","authors":"C. Fonseca, J. G. Mendonça Filho, C. Lézin, F. Baudin, António Donizeti de Oliveira, Jaqueline Torres Souza, L. V. Duarte","doi":"10.1144/SP514-2020-167","DOIUrl":"https://doi.org/10.1144/SP514-2020-167","url":null,"abstract":"Abstract The Toarcian Oceanic Anoxic Event (T-OAE) is marked by major palaeoenvironmental and palaeoceanographical changes on a global scale, associated with a severe disturbance of the global carbon cycle and organic-rich facies deposition. Here, a multiproxy approach (petrographic and geochemical techniques) was applied to the study of the organic content of the T-OAE of the Paris Basin, whose phytoplanktonic origin has been previously inferred by its geochemical signature. The top of the tenuicostatum Zone is characterized by palynomorphs and marine phytoplankton-derived amorphous organic matter (AOM), representing a proximal marine environment with emplacement of euxinic conditions at the top (total organic carbon/sulfur content and increase in AOM). At the base of the serpentinum Zone the proliferation of bacterial biomass begins, with phytoplankton playing a secondary role. This indicates the development of stagnant and restrictive conditions in a proximal environment, with water column stratification (neohop-13(18)-ene). The majority of the serpentinum Zone is dominated by bacterial biomass, suggesting a marine environment with bottom-water stagnation, possibly related to basin palaeogeomorphology and circulation patterns, with episodic euxinia. This therefore suggests that the T-OAE organic fraction is dominated by bacterial biomass, not phytoplankton, showing the importance of an integrated approach to the determination of the organic facies.","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"35 1","pages":"309 - 334"},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74806676","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. Lucas, J. Schneider, S. Nikolaeva, Xiandong Wang
Abstract The Carboniferous chronostratigraphic scale is a hierarchy of two subsystems, six series and seven stages developed during nearly two centuries of research. Carboniferous stage nomenclature developed with the proposal of numerous regional stages/substages based primarily on palaeobotanical, foraminiferal and ammonoid biostratigraphy, especially in Western Europe, the former Soviet Union, China and the USA. From the regional stages, seven ‘global stages’ have been identified (in ascending order): Tournaisian, Visean, Serpukhovian, Bashkirian, Moscovian, Kasimovian and Gzhelian. Three of the four ratified Carboniferous GSSPs use conodont evolutionary events as the primary signal for correlation – bases of Tournaisian, Bashkirian and base of Asselian. The GSSP of the Visean base has a foraminiferal event as its primary signal. Issues in the development of a Carboniferous chronostratigraphic scale include the rank of chronostratigraphic units, provinciality, conodont biostratigraphy, palaeobotanical biostratigraphy and the development of astrochronology and other methods of chronology and correlation.
{"title":"The Carboniferous chronostratigraphic scale: history, status and prospectus","authors":"S. Lucas, J. Schneider, S. Nikolaeva, Xiandong Wang","doi":"10.1144/SP512-2020-210","DOIUrl":"https://doi.org/10.1144/SP512-2020-210","url":null,"abstract":"Abstract The Carboniferous chronostratigraphic scale is a hierarchy of two subsystems, six series and seven stages developed during nearly two centuries of research. Carboniferous stage nomenclature developed with the proposal of numerous regional stages/substages based primarily on palaeobotanical, foraminiferal and ammonoid biostratigraphy, especially in Western Europe, the former Soviet Union, China and the USA. From the regional stages, seven ‘global stages’ have been identified (in ascending order): Tournaisian, Visean, Serpukhovian, Bashkirian, Moscovian, Kasimovian and Gzhelian. Three of the four ratified Carboniferous GSSPs use conodont evolutionary events as the primary signal for correlation – bases of Tournaisian, Bashkirian and base of Asselian. The GSSP of the Visean base has a foraminiferal event as its primary signal. Issues in the development of a Carboniferous chronostratigraphic scale include the rank of chronostratigraphic units, provinciality, conodont biostratigraphy, palaeobotanical biostratigraphy and the development of astrochronology and other methods of chronology and correlation.","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"89 1","pages":"19 - 48"},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87472347","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}
Abstract Micritic sediments containing dark, discrete, organic-rich burrows, situated in a light grey background carbonate mud, were deposited over a broad geographical area in deep-shelf, bathyal and basinal environments in the western margin of the Tethys Ocean during the Early and Middle Jurassic. These hemipelagic deposits represent a distinct depositional regime marked by low-energy, soft-bottom and only locally dysoxic environments. Still, it is unclear whether the trace-fossil assemblages occurring in these deposits pertain to a network of several community types – the ichnotaxa differing from basin to basin – or to a single community of environmentally broad-ranging, burrow-producing species. Lower Jurassic trace-fossil assemblages are found in the Western Carpathians and in the Subbetic, Betic Cordillera: that is, in basins separated by more than 2000 km in their original palaeogeographical areas. The stereotypical Chondrites and Zoophycos trace-fossil assemblages that occur in the analysed deposits share two ichnogenera of distinctive morphology (Lamellaeichnus and Teichichnus). Agglutinated foraminifera Bathysiphon occurs together with the described trace-fossil assemblage and determines the epibenthic palaeoenvironmental conditions. In the Western Carpathians, a Lamellaeichnus-dominated assemblage alternates with a Zoophycos-dominated assemblage in small, metre-scale cycles in the upper Pliensbachian, and the proportion of the Zoophycos assemblage increases stratigraphically upwards, probably owing to reduced basin ventilation during the early Toarcian. Within the southern Iberian palaeomargin, represented by the Betic Cordillera, Zoophycos is scarce in the facies.
{"title":"Palaeogeographical homogeneity of trace-fossil assemblages in Lower Jurassic spotted marls and limestones: comparison of the Western Carpathians and the Betic Cordillera","authors":"V. Šimo, M. Reolid","doi":"10.1144/SP514-2020-110","DOIUrl":"https://doi.org/10.1144/SP514-2020-110","url":null,"abstract":"Abstract Micritic sediments containing dark, discrete, organic-rich burrows, situated in a light grey background carbonate mud, were deposited over a broad geographical area in deep-shelf, bathyal and basinal environments in the western margin of the Tethys Ocean during the Early and Middle Jurassic. These hemipelagic deposits represent a distinct depositional regime marked by low-energy, soft-bottom and only locally dysoxic environments. Still, it is unclear whether the trace-fossil assemblages occurring in these deposits pertain to a network of several community types – the ichnotaxa differing from basin to basin – or to a single community of environmentally broad-ranging, burrow-producing species. Lower Jurassic trace-fossil assemblages are found in the Western Carpathians and in the Subbetic, Betic Cordillera: that is, in basins separated by more than 2000 km in their original palaeogeographical areas. The stereotypical Chondrites and Zoophycos trace-fossil assemblages that occur in the analysed deposits share two ichnogenera of distinctive morphology (Lamellaeichnus and Teichichnus). Agglutinated foraminifera Bathysiphon occurs together with the described trace-fossil assemblage and determines the epibenthic palaeoenvironmental conditions. In the Western Carpathians, a Lamellaeichnus-dominated assemblage alternates with a Zoophycos-dominated assemblage in small, metre-scale cycles in the upper Pliensbachian, and the proportion of the Zoophycos assemblage increases stratigraphically upwards, probably owing to reduced basin ventilation during the early Toarcian. Within the southern Iberian palaeomargin, represented by the Betic Cordillera, Zoophycos is scarce in the facies.","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"27 1","pages":"185 - 211"},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89957141","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}
Javier Fernández-Martínez, F. Rodríguez-Tovar, Laura Piñuela, F. Martínez-Ruiz, J. García-Ramos
Abstract Recent ichnological analysis conducted in two sections (Rodiles and Lastres) of the Asturian Basin revealed the presence of Halimedides Lorenz von Liburnau 1902, which occurs just above the black shales related to the end of the Toarcian Oceanic Anoxic Event (T-OAE). Halimedides is associated with recovery of the trace-maker community after the re-establishment of favourable, oxic, conditions. The appearance of Halimedides after the T-OAE event, previously not registered, supports the close relationship of the trace maker with oxygen conditions, as occurs in other anoxic events including the Cretaceous OAE-1a and OAE-2. Also, a relationship between morphometric and palaeoenvironmental parameters is observed: occurring larger and densely chambered specimens in darker, weakly oxygenated facies, while smaller and sparsely chambered forms are registered in lighter, better oxygenated sediments.
最近对阿斯图里亚盆地Rodiles和Lastres两个剖面进行的技术分析表明，在Toarcian Oceanic Anoxic Event (T-OAE)末期的黑色页岩上方发现了Halimedides Lorenz von Liburnau 1902。在重新建立有利的氧气条件后，halalimedides与痕迹制造者群落的恢复有关。在T-OAE事件之后出现的haalimedides，以前没有被记录，支持了痕迹制造者与氧气条件的密切关系，就像在其他缺氧事件中发生的那样，包括白垩纪OAE-1a和OAE-2。此外，还观察到形态测量学参数与古环境参数之间的关系:在较暗、含氧较弱的沉积物中出现较大且腔室密集的标本，而在较轻、含氧较好的沉积物中出现较小且腔室稀疏的标本。
{"title":"The Halimedides record in the Asturian Basin (northern Spain): supporting the Toarcian Oceanic Anoxic Event relationship","authors":"Javier Fernández-Martínez, F. Rodríguez-Tovar, Laura Piñuela, F. Martínez-Ruiz, J. García-Ramos","doi":"10.1144/SP514-2020-156","DOIUrl":"https://doi.org/10.1144/SP514-2020-156","url":null,"abstract":"Abstract Recent ichnological analysis conducted in two sections (Rodiles and Lastres) of the Asturian Basin revealed the presence of Halimedides Lorenz von Liburnau 1902, which occurs just above the black shales related to the end of the Toarcian Oceanic Anoxic Event (T-OAE). Halimedides is associated with recovery of the trace-maker community after the re-establishment of favourable, oxic, conditions. The appearance of Halimedides after the T-OAE event, previously not registered, supports the close relationship of the trace maker with oxygen conditions, as occurs in other anoxic events including the Cretaceous OAE-1a and OAE-2. Also, a relationship between morphometric and palaeoenvironmental parameters is observed: occurring larger and densely chambered specimens in darker, weakly oxygenated facies, while smaller and sparsely chambered forms are registered in lighter, better oxygenated sediments.","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"12 1","pages":"173 - 184"},"PeriodicalIF":0.0,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87812318","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}
C. Bădăluţă, D. Mihăilă, D. Mihǎilǎ, Gheorghe Bădăluţă, Petruț-Ionel Bistricean
Abstract Water, the vital element of the environment, considered for long time an inexhaustible and renewable resource, can have a limiting or favourable potential in the socioeconomic development of a region. Given that Romania's NE (Eastern Carpathians and the northwestern part of the Moldova Plateau) is undergoing increased competition for water resources, triggered by the intensification of agriculture and industrial development, better knowledge of the hydrological processes and the quality of surface water is required. The main purpose of the present study was to identify the hydrological processes determining the quality of surface waters based on analyses of the stable isotopic composition of water from precipitation, rivers and lakes and its quality parameters. For this, water samples were collected from 29 river sections, two lakes and a precipitation monitoring point over a period of 12 months (January to December 2019). The results show that the changes in the isotopic composition of precipitation and surface water are mainly controlled by air temperature, which, in turn, is influenced by the large-scale atmospheric circulation and other factors (e.g. precipitation amount, season, altitude). At the same time, the chemical analyses indicate that the water resources of the study area are predominantly characterized by a good chemical and ecological state, except for two sampling points with a moderate state and three with a poor ecological state.
{"title":"Stable isotopic and geochemical characterization of precipitation and riverine waters in the Eastern Carpathians and links with large-scale drivers","authors":"C. Bădăluţă, D. Mihăilă, D. Mihǎilǎ, Gheorghe Bădăluţă, Petruț-Ionel Bistricean","doi":"10.1144/SP507-2020-154","DOIUrl":"https://doi.org/10.1144/SP507-2020-154","url":null,"abstract":"Abstract Water, the vital element of the environment, considered for long time an inexhaustible and renewable resource, can have a limiting or favourable potential in the socioeconomic development of a region. Given that Romania's NE (Eastern Carpathians and the northwestern part of the Moldova Plateau) is undergoing increased competition for water resources, triggered by the intensification of agriculture and industrial development, better knowledge of the hydrological processes and the quality of surface water is required. The main purpose of the present study was to identify the hydrological processes determining the quality of surface waters based on analyses of the stable isotopic composition of water from precipitation, rivers and lakes and its quality parameters. For this, water samples were collected from 29 river sections, two lakes and a precipitation monitoring point over a period of 12 months (January to December 2019). The results show that the changes in the isotopic composition of precipitation and surface water are mainly controlled by air temperature, which, in turn, is influenced by the large-scale atmospheric circulation and other factors (e.g. precipitation amount, season, altitude). At the same time, the chemical analyses indicate that the water resources of the study area are predominantly characterized by a good chemical and ecological state, except for two sampling points with a moderate state and three with a poor ecological state.","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"73 1","pages":"107 - 131"},"PeriodicalIF":0.0,"publicationDate":"2021-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83113636","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}
N. Tabor, A. Hope Jahren, L. Wyman, M. Feseha, L. Todd, J. Kappleman
Abstract Several years of weekly sampling of waters from the Shinfa River watershed in the lowlands of northwestern Ethiopia yielded 275 samples with δDvsmow and δ18Ovsmow values ranging from c. −10 to +100‰ and from c. −2 to +20‰, respectively. Wet season (summertime) Shinfa River water stable hydrogen and oxygen isotope values are among the lowest reported in this study, whereas the dry season (winter/spring) usually records a progressive trend towards +100 and +20‰, respectively. Overlapping with this interval of Shinfa River water sampling, air temperatures (n = 155) also were recorded at the same time; temperatures range from c. 18 to 47°C. The coolest temperatures occur during the summer wet season, associated with the arrival of the Kiremt rains in the region, whereas the warmest temperatures occur towards the end of the dry season. In order to evaluate the extent to which this rather extreme isotope hydrology is recorded in the sediments and biota of the Shinfa River system, both hardwater calcareous deposits precipitated on basalt cobbles by evaporation in the Shinfa River channel during the dry season and aragonite from three different modern bivalve mollusc species were collected and analysed for their stable oxygen and carbon isotope compositions. Hardwater calcareous deposit δ18Ovpdb and δ13Cvpdb values range from c. −2 to +5‰ and c. −9 to +7‰, respectively, and preserve a trend towards progressively more positive δ18Ovpdb and δ13Cvpdb values through the course of the dry season. Shinfa River mollusc aragonite powders (n = 51) were serially sampled from cf. Coelutura aegyptica, cf. Chambardia rubens and Etheria elliptica species. All species record oxygen and carbon isotopes between c. −2 and +7‰ and between c. −18 and −8‰, and each species records coherent trends between those extremes as well as a positive parametric correlation between measured oxygen and carbon isotope values. However, there does appear to be some variability of measured isotope values by species, suggesting that species-specific metabolic differences may impact the resulting range of aragonite stable carbon and oxygen values. Based upon the measured Shinfa River water δ18Ovsmow and corresponding water temperatures at the time of sampling, a possible range of Shinfa River calcite and aragonite δ18Ovpdb values were calculated in conjunction with well-established calcite–water and aragonite–water oxygen isotope fractionation equations. These ‘fictive’ calcite and aragonite δ18Ovpdb values range from c. −5 to +15‰, which is a much larger range than previously documented from analyses of the hardwater calcareous deposits and mollusc aragonite samples. The narrower range of values in the natural calcite and aragonite samples may be attributed to several mechanisms, including time averaging and environmental stress. Nevertheless, the stable oxygen isotopic compositions of these natural samples offer a minimum assessment of the environmental extremes which occur in this
{"title":"Stable isotope geochemistry of the modern Shinfa River, northwestern Ethiopian lowlands: a potential model for interpreting ancient environments of the Middle Stone Age","authors":"N. Tabor, A. Hope Jahren, L. Wyman, M. Feseha, L. Todd, J. Kappleman","doi":"10.1144/SP507-2020-219","DOIUrl":"https://doi.org/10.1144/SP507-2020-219","url":null,"abstract":"Abstract Several years of weekly sampling of waters from the Shinfa River watershed in the lowlands of northwestern Ethiopia yielded 275 samples with δDvsmow and δ18Ovsmow values ranging from c. −10 to +100‰ and from c. −2 to +20‰, respectively. Wet season (summertime) Shinfa River water stable hydrogen and oxygen isotope values are among the lowest reported in this study, whereas the dry season (winter/spring) usually records a progressive trend towards +100 and +20‰, respectively. Overlapping with this interval of Shinfa River water sampling, air temperatures (n = 155) also were recorded at the same time; temperatures range from c. 18 to 47°C. The coolest temperatures occur during the summer wet season, associated with the arrival of the Kiremt rains in the region, whereas the warmest temperatures occur towards the end of the dry season. In order to evaluate the extent to which this rather extreme isotope hydrology is recorded in the sediments and biota of the Shinfa River system, both hardwater calcareous deposits precipitated on basalt cobbles by evaporation in the Shinfa River channel during the dry season and aragonite from three different modern bivalve mollusc species were collected and analysed for their stable oxygen and carbon isotope compositions. Hardwater calcareous deposit δ18Ovpdb and δ13Cvpdb values range from c. −2 to +5‰ and c. −9 to +7‰, respectively, and preserve a trend towards progressively more positive δ18Ovpdb and δ13Cvpdb values through the course of the dry season. Shinfa River mollusc aragonite powders (n = 51) were serially sampled from cf. Coelutura aegyptica, cf. Chambardia rubens and Etheria elliptica species. All species record oxygen and carbon isotopes between c. −2 and +7‰ and between c. −18 and −8‰, and each species records coherent trends between those extremes as well as a positive parametric correlation between measured oxygen and carbon isotope values. However, there does appear to be some variability of measured isotope values by species, suggesting that species-specific metabolic differences may impact the resulting range of aragonite stable carbon and oxygen values. Based upon the measured Shinfa River water δ18Ovsmow and corresponding water temperatures at the time of sampling, a possible range of Shinfa River calcite and aragonite δ18Ovpdb values were calculated in conjunction with well-established calcite–water and aragonite–water oxygen isotope fractionation equations. These ‘fictive’ calcite and aragonite δ18Ovpdb values range from c. −5 to +15‰, which is a much larger range than previously documented from analyses of the hardwater calcareous deposits and mollusc aragonite samples. The narrower range of values in the natural calcite and aragonite samples may be attributed to several mechanisms, including time averaging and environmental stress. Nevertheless, the stable oxygen isotopic compositions of these natural samples offer a minimum assessment of the environmental extremes which occur in this","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"61 1","pages":"225 - 253"},"PeriodicalIF":0.0,"publicationDate":"2021-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86044211","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}
Abstract Earthquakes and tsunamis are high-impact geohazard events that can be extremely destructive when they occur at large magnitudes and intensities, although their causes and potential locations are, for the most part, predictable within the framework of plate tectonics. Amongst the main reasons for their high impact include enormous numbers of casualties, extensive property damage in vast areas and significant social and economic disruption in urban settings where populous residential areas, global banking centres, industrial factories and critical facilities (nuclear power plants, dams) may be located. In order to reduce the impact of these geohazards, nations, societies, professional organizations and governments need to collaborate to prepare more effective seismic and tsunami risk assessments, disaster management plans, educational and training programmes for increased preparedness of the public, and strategic plans and objectives for capacity building, skill and knowledge transfer, and building of societal resilience. Improved building design and construction codes and emergency preparedness and evacuation plans should be part of disaster management plans in countries where destructive earthquakes and tsunamis have occurred. The rapid increases in population along coastal corridors in developing and developed countries is likely to escalate the social and economic impacts of these geohazards exponentially in the future. The chapters in this book present case studies of some of the most salient earthquake and tsunami events in historical and modern times, their origins and manifestations, and efforts and the most effective practices of risk assessment and disaster management implemented by various governments, international organizations and inter-governmental agencies following these events. New methods of computing probabilistic seismic hazard risks, delineating respect distance and damage zones along and across seismically active faults and recognizing tsunamigenic and submarine landslides on the seafloor are introduced. The conclusions presented in the chapters show that: (1) scientific understanding of the characteristics of seismically active faults is paramount; (2) increased local (community), national and global resilience is necessary to empower societal preparedness for earthquake and tsunami events; and, (3) all stakeholders, including policy-makers, scientists, local, state and national governments, media and world organizations (UNESCO, IUGS, GeoHazards International, Global Geodetic Observing System, National Earthquake Hazards Reduction Program) must work together to disseminate accurate and timely information on geohazards, to develop effective legislation for risk reduction and to prepare realistic and practical hazard mitigation and management measures.
{"title":"Characterization of modern and historical seismic–tsunamic events and their global–societal impacts","authors":"Y. Dilek, Y. Ogawa, Y. Okubo","doi":"10.1144/SP501-2021-17","DOIUrl":"https://doi.org/10.1144/SP501-2021-17","url":null,"abstract":"Abstract Earthquakes and tsunamis are high-impact geohazard events that can be extremely destructive when they occur at large magnitudes and intensities, although their causes and potential locations are, for the most part, predictable within the framework of plate tectonics. Amongst the main reasons for their high impact include enormous numbers of casualties, extensive property damage in vast areas and significant social and economic disruption in urban settings where populous residential areas, global banking centres, industrial factories and critical facilities (nuclear power plants, dams) may be located. In order to reduce the impact of these geohazards, nations, societies, professional organizations and governments need to collaborate to prepare more effective seismic and tsunami risk assessments, disaster management plans, educational and training programmes for increased preparedness of the public, and strategic plans and objectives for capacity building, skill and knowledge transfer, and building of societal resilience. Improved building design and construction codes and emergency preparedness and evacuation plans should be part of disaster management plans in countries where destructive earthquakes and tsunamis have occurred. The rapid increases in population along coastal corridors in developing and developed countries is likely to escalate the social and economic impacts of these geohazards exponentially in the future. The chapters in this book present case studies of some of the most salient earthquake and tsunami events in historical and modern times, their origins and manifestations, and efforts and the most effective practices of risk assessment and disaster management implemented by various governments, international organizations and inter-governmental agencies following these events. New methods of computing probabilistic seismic hazard risks, delineating respect distance and damage zones along and across seismically active faults and recognizing tsunamigenic and submarine landslides on the seafloor are introduced. The conclusions presented in the chapters show that: (1) scientific understanding of the characteristics of seismically active faults is paramount; (2) increased local (community), national and global resilience is necessary to empower societal preparedness for earthquake and tsunami events; and, (3) all stakeholders, including policy-makers, scientists, local, state and national governments, media and world organizations (UNESCO, IUGS, GeoHazards International, Global Geodetic Observing System, National Earthquake Hazards Reduction Program) must work together to disseminate accurate and timely information on geohazards, to develop effective legislation for risk reduction and to prepare realistic and practical hazard mitigation and management measures.","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"130 1","pages":"1 - 22"},"PeriodicalIF":0.0,"publicationDate":"2021-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79597122","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}
Abstract The Zagros Fold and Thrust Belt (ZFTB) in southern Iran is a seismically active tectonic zone, where SW-vergent thrust faults and NW–SE- and NE–SW-oriented strike-slip fault systems accommodate crustal shortening, resulting from the active Arabia–Eurasia collision. The majority of earthquakes in Iran occur within the ZFTB, posing a major hazard for society. The 9 April 2013 Kaki Earthquake (Mw 6.3) in the southern part of the ZFTB took place along a fault that was previously unknown regarding its surface expression, geometry and kinematics. We have used surface–subsurface distributions and focal mechanism solutions of the Kaki Earthquake aftershocks to characterize the fault system responsible for the quake. Our results indicate that it was a NE-vergent thrust fault with a minor dextral component that slipped c. 7–17 km at depth, causing the Kaki Earthquake. There were no surface ruptures, although some surface fissures developed in fluvial terraces during the main shock. We interpret this fault as a blind backthrust, which probably represents a reactivated Mesozoic basement fault emanating from the Zagros detachment surface. An upper shallow décollement zone within the Miocene Gachsaran Salt facilitated its upward propagation on the back-limb of an overturned syncline.
{"title":"The 9 April 2013 Kaki earthquake (Mw 6.3) in SW Iran occurred along a blind backthrust in the Fars geological province of the Zagros Fold and Thrust Belt","authors":"Marzieh Khalili, Y. Dilek","doi":"10.1144/SP501-2021-20","DOIUrl":"https://doi.org/10.1144/SP501-2021-20","url":null,"abstract":"Abstract The Zagros Fold and Thrust Belt (ZFTB) in southern Iran is a seismically active tectonic zone, where SW-vergent thrust faults and NW–SE- and NE–SW-oriented strike-slip fault systems accommodate crustal shortening, resulting from the active Arabia–Eurasia collision. The majority of earthquakes in Iran occur within the ZFTB, posing a major hazard for society. The 9 April 2013 Kaki Earthquake (Mw 6.3) in the southern part of the ZFTB took place along a fault that was previously unknown regarding its surface expression, geometry and kinematics. We have used surface–subsurface distributions and focal mechanism solutions of the Kaki Earthquake aftershocks to characterize the fault system responsible for the quake. Our results indicate that it was a NE-vergent thrust fault with a minor dextral component that slipped c. 7–17 km at depth, causing the Kaki Earthquake. There were no surface ruptures, although some surface fissures developed in fluvial terraces during the main shock. We interpret this fault as a blind backthrust, which probably represents a reactivated Mesozoic basement fault emanating from the Zagros detachment surface. An upper shallow décollement zone within the Miocene Gachsaran Salt facilitated its upward propagation on the back-limb of an overturned syncline.","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"266 1","pages":"71 - 85"},"PeriodicalIF":0.0,"publicationDate":"2021-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82994215","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}
Alok Kumar, D. Talukdar, N. V. C. Rao, R. Burgess, B. Lehmann
Abstract We report Mesoproterozoic 40Ar–39Ar (whole-rock) ages of lamproites from (i) the Ramadugu field (R4 dyke : 1434 ± 19 Ma and R5 dyke: 1334 ± 12 Ma) and the Krishna field (Pochampalle dyke: 1439 ± 3 Ma and Tirumalgiri dyke: 1256 ± 12 Ma) from the Eastern Dharwar Craton (EDC) and (ii) the Garledinne (1433 ± 8 Ma) and the Chelima (1373 ± 6 Ma) dykes from within the Paleo-Mesoproterozoic Cuddapah Basin, southern India. The ages reported for the Ramadugu and Tirumalgiri lamproites constitute their first radiometric dates. Ages of the Pochampalle and the Chelima lamproites from this study are broadly comparable to their previously reported 40Ar–39Ar (phlogopite) ages of c. 1500 Ma and 1418 ± 8 Ma, respectively. The ages of all these lamproites are much older than those of the (i) c. 1.1 Ga kimberlites from the Wajrakarur and Narayanpet fields of the EDC and (ii) c. 1.09 Ga lamproitic dykes at Zangamarajupalle which intrude the Cumbum Formation of the Cuddapah Basin. However, the age of the Tirumalgiri lamproite (c. 1256 Ma) is similar to that of the Ramannapeta lamproite (c. 1224 Ma) within the Krishna field. Our study provides evidence for protracted ultrapotassic (lamproitic) magmatism from c. 1.43 to 1.1 Ga over a widespread area (c. 2500 km2) in and around the Cuddapah Basin and the EDC. Implications of the obtained new ages for the diamond provenance of the Banganapalle Conglomerates, the age of the Kurnool Group and for the timing of break-up of the Paleo-Mesoproterozoic supercontinent of Columbia/Nuna are explored.
{"title":"Mesoproterozoic 40Ar–39Ar ages of some lamproites from the Cuddapah Basin and Eastern Dharwar Craton, southern India: implications for diamond provenance of the Banganapalle Conglomerates, age of the Kurnool Group and Columbia tectonics","authors":"Alok Kumar, D. Talukdar, N. V. C. Rao, R. Burgess, B. Lehmann","doi":"10.1144/SP513-2020-247","DOIUrl":"https://doi.org/10.1144/SP513-2020-247","url":null,"abstract":"Abstract We report Mesoproterozoic 40Ar–39Ar (whole-rock) ages of lamproites from (i) the Ramadugu field (R4 dyke : 1434 ± 19 Ma and R5 dyke: 1334 ± 12 Ma) and the Krishna field (Pochampalle dyke: 1439 ± 3 Ma and Tirumalgiri dyke: 1256 ± 12 Ma) from the Eastern Dharwar Craton (EDC) and (ii) the Garledinne (1433 ± 8 Ma) and the Chelima (1373 ± 6 Ma) dykes from within the Paleo-Mesoproterozoic Cuddapah Basin, southern India. The ages reported for the Ramadugu and Tirumalgiri lamproites constitute their first radiometric dates. Ages of the Pochampalle and the Chelima lamproites from this study are broadly comparable to their previously reported 40Ar–39Ar (phlogopite) ages of c. 1500 Ma and 1418 ± 8 Ma, respectively. The ages of all these lamproites are much older than those of the (i) c. 1.1 Ga kimberlites from the Wajrakarur and Narayanpet fields of the EDC and (ii) c. 1.09 Ga lamproitic dykes at Zangamarajupalle which intrude the Cumbum Formation of the Cuddapah Basin. However, the age of the Tirumalgiri lamproite (c. 1256 Ma) is similar to that of the Ramannapeta lamproite (c. 1224 Ma) within the Krishna field. Our study provides evidence for protracted ultrapotassic (lamproitic) magmatism from c. 1.43 to 1.1 Ga over a widespread area (c. 2500 km2) in and around the Cuddapah Basin and the EDC. Implications of the obtained new ages for the diamond provenance of the Banganapalle Conglomerates, the age of the Kurnool Group and for the timing of break-up of the Paleo-Mesoproterozoic supercontinent of Columbia/Nuna are explored.","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"38 1","pages":"157 - 178"},"PeriodicalIF":0.0,"publicationDate":"2021-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77051748","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 Geological Society of London was founded in 1807. At the time, membership was restricted to men, many of whom became well-known names in the history of the geological sciences. On the 21 May 1919, the first female Fellows were elected to the Society, 112 years after its formation. This Special Publication celebrates the centenary of that important event. In doing so it presents the often untold stories of pioneering women geoscientists from across the world who navigated male-dominated academia and learned societies, experienced the harsh realities of Siberian field-exploration, or responded to the strategic necessity of the ‘petroleum girls’ in early American oil exploration and production. It uncovers important female role models in the history of science, and investigates why not all of these women received due recognition from their contemporaries and peers. The work has identified a number of common issues that sometimes led to original work and personal achievements being lost or unacknowledged, and as a consequence, to histories being unwritten.
{"title":"About this title - Celebrating 100 Years of Female Fellowship of the Geological Society: Discovering Forgotten Histories","authors":"C. Burek, B. Higgs","doi":"10.1144/sp506","DOIUrl":"https://doi.org/10.1144/sp506","url":null,"abstract":"The Geological Society of London was founded in 1807. At the time, membership was restricted to men, many of whom became well-known names in the history of the geological sciences. On the 21 May 1919, the first female Fellows were elected to the Society, 112 years after its formation. This Special Publication celebrates the centenary of that important event. In doing so it presents the often untold stories of pioneering women geoscientists from across the world who navigated male-dominated academia and learned societies, experienced the harsh realities of Siberian field-exploration, or responded to the strategic necessity of the ‘petroleum girls’ in early American oil exploration and production. It uncovers important female role models in the history of science, and investigates why not all of these women received due recognition from their contemporaries and peers. The work has identified a number of common issues that sometimes led to original work and personal achievements being lost or unacknowledged, and as a consequence, to histories being unwritten.","PeriodicalId":22055,"journal":{"name":"Special Publications","volume":"202 1","pages":"NP - NP"},"PeriodicalIF":0.0,"publicationDate":"2021-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75576033","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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