Pub Date : 2024-07-03DOI: 10.1038/s41561-024-01471-9
Cécile L. Blanchet, Arne Ramisch, Rik Tjallingii, Monica Ionita, Louison Laruelle, Meike Bagge, Volker Klemann, Achim Brauer
Understanding how large river systems will respond to an invigorated hydrological cycle as simulated under higher global temperatures is a pressing issue. Insights can be gained from studying past wetter-than-present intervals, such as the North African Humid Period during the early Holocene Epoch (~11–6 thousand years ago). Here we present a 1,500-year-long annually laminated (varved) offshore sediment record that tracks the seasonal discharge of the Nile River during the North African Humid Period. The record reveals mobilization of large amounts of sediments during strong summer floods that may have rendered the Nile valley uninhabitable. More frequent and rapid transitions between extremely strong and weak floods between 9.2 and 8.6 thousand years ago indicate highly instable fluvial dynamics. Climate simulations suggest flood variability was paced by El Niño/Southern Oscillation on interannual timescales, while multi-decadal oscillatory modes drove changes in extreme flood events. These pacemakers have also been identified in the Nile flow records from the Common Era, which implies their stationarity under contrasting hydroclimatic conditions. Extreme and highly variable summer floods in the Nile River valley through the North African Humid Period were modulated by both interannual and multi-decadal climate modes, according to an offshore sedimentary archive.
{"title":"Climatic pacing of extreme Nile floods during the North African Humid Period","authors":"Cécile L. Blanchet, Arne Ramisch, Rik Tjallingii, Monica Ionita, Louison Laruelle, Meike Bagge, Volker Klemann, Achim Brauer","doi":"10.1038/s41561-024-01471-9","DOIUrl":"10.1038/s41561-024-01471-9","url":null,"abstract":"Understanding how large river systems will respond to an invigorated hydrological cycle as simulated under higher global temperatures is a pressing issue. Insights can be gained from studying past wetter-than-present intervals, such as the North African Humid Period during the early Holocene Epoch (~11–6 thousand years ago). Here we present a 1,500-year-long annually laminated (varved) offshore sediment record that tracks the seasonal discharge of the Nile River during the North African Humid Period. The record reveals mobilization of large amounts of sediments during strong summer floods that may have rendered the Nile valley uninhabitable. More frequent and rapid transitions between extremely strong and weak floods between 9.2 and 8.6 thousand years ago indicate highly instable fluvial dynamics. Climate simulations suggest flood variability was paced by El Niño/Southern Oscillation on interannual timescales, while multi-decadal oscillatory modes drove changes in extreme flood events. These pacemakers have also been identified in the Nile flow records from the Common Era, which implies their stationarity under contrasting hydroclimatic conditions. Extreme and highly variable summer floods in the Nile River valley through the North African Humid Period were modulated by both interannual and multi-decadal climate modes, according to an offshore sedimentary archive.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":null,"pages":null},"PeriodicalIF":15.7,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01471-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141496044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-02DOI: 10.1038/s41561-024-01473-7
Yuan Xie, Attila Balázs, Taras Gerya, Xiong Xiong
The geodynamic evolution of the Tibetan Plateau remains highly debated. Any model of its evolution must explain the plateau’s growth as constrained by palaeo-altitude studies, the spatio-temporal distribution of magmatic activity, and the lithospheric mantle removal inferred from seismic velocity anomalies in the underlying mantle. Several conflicting models have been proposed, but none of these explains the first-order topographic, magmatic and seismic features self-consistently. Here we propose and test numerically an evolutionary model of the plateau that involves gradual peeling of the lithospheric mantle from the overriding plate and consequent mantle and crustal melting and uplift. We show that this model successfully reproduces the successive surface uplift of the plateau to more than 4 km above sea level and is consistent with the observed migration of magmatism and geometry of the lithosphere–asthenosphere boundary resulting from subduction of the Indian plate and delamination of the mantle lithosphere of the Eurasian plate. These comparisons indicate that mantle delamination from the overriding plate is the driving force behind the uplift of the Tibetan Plateau and, potentially, orogenic plateaus more generally. Delamination of the lithospheric mantle from the overriding Eurasian plate below the Tibetan Plateau is consistent with topographic, magmatic and seismic observations, according to numerical simulations of the geodynamic evolution of the plateau.
{"title":"Uplift of the Tibetan Plateau driven by mantle delamination from the overriding plate","authors":"Yuan Xie, Attila Balázs, Taras Gerya, Xiong Xiong","doi":"10.1038/s41561-024-01473-7","DOIUrl":"10.1038/s41561-024-01473-7","url":null,"abstract":"The geodynamic evolution of the Tibetan Plateau remains highly debated. Any model of its evolution must explain the plateau’s growth as constrained by palaeo-altitude studies, the spatio-temporal distribution of magmatic activity, and the lithospheric mantle removal inferred from seismic velocity anomalies in the underlying mantle. Several conflicting models have been proposed, but none of these explains the first-order topographic, magmatic and seismic features self-consistently. Here we propose and test numerically an evolutionary model of the plateau that involves gradual peeling of the lithospheric mantle from the overriding plate and consequent mantle and crustal melting and uplift. We show that this model successfully reproduces the successive surface uplift of the plateau to more than 4 km above sea level and is consistent with the observed migration of magmatism and geometry of the lithosphere–asthenosphere boundary resulting from subduction of the Indian plate and delamination of the mantle lithosphere of the Eurasian plate. These comparisons indicate that mantle delamination from the overriding plate is the driving force behind the uplift of the Tibetan Plateau and, potentially, orogenic plateaus more generally. Delamination of the lithospheric mantle from the overriding Eurasian plate below the Tibetan Plateau is consistent with topographic, magmatic and seismic observations, according to numerical simulations of the geodynamic evolution of the plateau.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":null,"pages":null},"PeriodicalIF":15.7,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01473-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-02DOI: 10.1038/s41561-024-01488-0
High-resolution numerical simulations show that subduction of the Indian plate peeled off the mantle lithosphere from the Tibetan Plateau. This process successfully explains first-order observations of the stepwise growth of the plateau, the migration of magmatism in the region and its seismic properties.
{"title":"The rise of the Tibetan Plateau was controlled by overriding plate mantle delamination","authors":"","doi":"10.1038/s41561-024-01488-0","DOIUrl":"10.1038/s41561-024-01488-0","url":null,"abstract":"High-resolution numerical simulations show that subduction of the Indian plate peeled off the mantle lithosphere from the Tibetan Plateau. This process successfully explains first-order observations of the stepwise growth of the plateau, the migration of magmatism in the region and its seismic properties.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":null,"pages":null},"PeriodicalIF":15.7,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-02DOI: 10.1038/s41561-024-01479-1
Richard G. Stockey, Devon B. Cole, Una C. Farrell, Heda Agić, Thomas H. Boag, Jochen J. Brocks, Don E. Canfield, Meng Cheng, Peter W. Crockford, Huan Cui, Tais W. Dahl, Lucas Del Mouro, Keith Dewing, Stephen Q. Dornbos, Joseph F. Emmings, Robert R. Gaines, Timothy M. Gibson, Benjamin C. Gill, Geoffrey J. Gilleaudeau, Karin Goldberg, Romain Guilbaud, Galen Halverson, Emma U. Hammarlund, Kalev Hantsoo, Miles A. Henderson, Charles M. Henderson, Malcolm S. W. Hodgskiss, Amber J. M. Jarrett, David T. Johnston, Pavel Kabanov, Julien Kimmig, Andrew H. Knoll, Marcus Kunzmann, Matthew A. LeRoy, Chao Li, David K. Loydell, Francis A. Macdonald, Joseph M. Magnall, N. Tanner Mills, Lawrence M. Och, Brennan O’Connell, Anais Pagès, Shanan E. Peters, Susannah M. Porter, Simon W. Poulton, Samantha R. Ritzer, Alan D. Rooney, Shane Schoepfer, Emily F. Smith, Justin V. Strauss, Gabriel Jubé Uhlein, Tristan White, Rachel A. Wood, Christina R. Woltz, Inessa Yurchenko, Noah J. Planavsky, Erik A. Sperling
A geologically rapid Neoproterozoic oxygenation event is commonly linked to the appearance of marine animal groups in the fossil record. However, there is still debate about what evidence from the sedimentary geochemical record—if any—provides strong support for a persistent shift in surface oxygen immediately preceding the rise of animals. We present statistical learning analyses of a large dataset of geochemical data and associated geological context from the Neoproterozoic and Palaeozoic sedimentary record and then use Earth system modelling to link trends in redox-sensitive trace metal and organic carbon concentrations to the oxygenation of Earth’s oceans and atmosphere. We do not find evidence for the wholesale oxygenation of Earth’s oceans in the late Neoproterozoic era. We do, however, reconstruct a moderate long-term increase in atmospheric oxygen and marine productivity. These changes to the Earth system would have increased dissolved oxygen and food supply in shallow-water habitats during the broad interval of geologic time in which the major animal groups first radiated. This approach provides some of the most direct evidence for potential physiological drivers of the Cambrian radiation, while highlighting the importance of later Palaeozoic oxygenation in the evolution of the modern Earth system. Oxygen in shallow shelf waters rose linearly with atmospheric oxygen in the Neoproterozoic era, potentially driving the first radiation of marine animals, but widespread ocean oxygenation came later, according to reconstructions of oxygen levels and marine productivity.
{"title":"Sustained increases in atmospheric oxygen and marine productivity in the Neoproterozoic and Palaeozoic eras","authors":"Richard G. Stockey, Devon B. Cole, Una C. Farrell, Heda Agić, Thomas H. Boag, Jochen J. Brocks, Don E. Canfield, Meng Cheng, Peter W. Crockford, Huan Cui, Tais W. Dahl, Lucas Del Mouro, Keith Dewing, Stephen Q. Dornbos, Joseph F. Emmings, Robert R. Gaines, Timothy M. Gibson, Benjamin C. Gill, Geoffrey J. Gilleaudeau, Karin Goldberg, Romain Guilbaud, Galen Halverson, Emma U. Hammarlund, Kalev Hantsoo, Miles A. Henderson, Charles M. Henderson, Malcolm S. W. Hodgskiss, Amber J. M. Jarrett, David T. Johnston, Pavel Kabanov, Julien Kimmig, Andrew H. Knoll, Marcus Kunzmann, Matthew A. LeRoy, Chao Li, David K. Loydell, Francis A. Macdonald, Joseph M. Magnall, N. Tanner Mills, Lawrence M. Och, Brennan O’Connell, Anais Pagès, Shanan E. Peters, Susannah M. Porter, Simon W. Poulton, Samantha R. Ritzer, Alan D. Rooney, Shane Schoepfer, Emily F. Smith, Justin V. Strauss, Gabriel Jubé Uhlein, Tristan White, Rachel A. Wood, Christina R. Woltz, Inessa Yurchenko, Noah J. Planavsky, Erik A. Sperling","doi":"10.1038/s41561-024-01479-1","DOIUrl":"10.1038/s41561-024-01479-1","url":null,"abstract":"A geologically rapid Neoproterozoic oxygenation event is commonly linked to the appearance of marine animal groups in the fossil record. However, there is still debate about what evidence from the sedimentary geochemical record—if any—provides strong support for a persistent shift in surface oxygen immediately preceding the rise of animals. We present statistical learning analyses of a large dataset of geochemical data and associated geological context from the Neoproterozoic and Palaeozoic sedimentary record and then use Earth system modelling to link trends in redox-sensitive trace metal and organic carbon concentrations to the oxygenation of Earth’s oceans and atmosphere. We do not find evidence for the wholesale oxygenation of Earth’s oceans in the late Neoproterozoic era. We do, however, reconstruct a moderate long-term increase in atmospheric oxygen and marine productivity. These changes to the Earth system would have increased dissolved oxygen and food supply in shallow-water habitats during the broad interval of geologic time in which the major animal groups first radiated. This approach provides some of the most direct evidence for potential physiological drivers of the Cambrian radiation, while highlighting the importance of later Palaeozoic oxygenation in the evolution of the modern Earth system. Oxygen in shallow shelf waters rose linearly with atmospheric oxygen in the Neoproterozoic era, potentially driving the first radiation of marine animals, but widespread ocean oxygenation came later, according to reconstructions of oxygen levels and marine productivity.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":null,"pages":null},"PeriodicalIF":15.7,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01479-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-01DOI: 10.1038/s41561-024-01469-3
Russell Deitrick, Colin Goldblatt
Solar heating causes the periodic expansion and contraction of Earth’s atmosphere known as the atmospheric tide. This is observed at the surface as a semidiurnal pressure oscillation that appears to influence convection and rainfall. Roughly 0.5 to 1.0 billion years ago, when day length was roughly 21–22 hours, the tide would have been resonant, or close in frequency, with atmospheric Lamb waves of 10.5–11.0 hour periods. This ‘Lamb resonance’ would have amplified the pressure oscillation, perhaps strongly enough to affect the global or tropical climate. Here we run a general circulation model at different rotation rates to model the resonance and its impact on climate. The resonance exerts a dominant control on tropical cloud cover, convection and rainfall: sunrise and sunset are cloudy and rainy, whereas midday and midnight are clear and dry. Generally clear skies at noon lower the albedo, contributing 2–4 K warming in the global average, which would have helped counter the 10% fainter Sun. The hydrological cycle becomes more active, and the atmosphere moister. Our work highlights the role of tidally induced adiabatic expansion in controlling tropical precipitation, helping explain modern-day observations of a semidiurnal rainfall pattern. Climate simulations suggest atmospheric tides in resonance with atmospheric waves on early Earth when days were shorter could have modified tropical convection patterns and warmed the planet despite a fainter Sun.
{"title":"Past Earth warmed by tidal resonance-induced organization of clouds under a shorter day","authors":"Russell Deitrick, Colin Goldblatt","doi":"10.1038/s41561-024-01469-3","DOIUrl":"10.1038/s41561-024-01469-3","url":null,"abstract":"Solar heating causes the periodic expansion and contraction of Earth’s atmosphere known as the atmospheric tide. This is observed at the surface as a semidiurnal pressure oscillation that appears to influence convection and rainfall. Roughly 0.5 to 1.0 billion years ago, when day length was roughly 21–22 hours, the tide would have been resonant, or close in frequency, with atmospheric Lamb waves of 10.5–11.0 hour periods. This ‘Lamb resonance’ would have amplified the pressure oscillation, perhaps strongly enough to affect the global or tropical climate. Here we run a general circulation model at different rotation rates to model the resonance and its impact on climate. The resonance exerts a dominant control on tropical cloud cover, convection and rainfall: sunrise and sunset are cloudy and rainy, whereas midday and midnight are clear and dry. Generally clear skies at noon lower the albedo, contributing 2–4 K warming in the global average, which would have helped counter the 10% fainter Sun. The hydrological cycle becomes more active, and the atmosphere moister. Our work highlights the role of tidally induced adiabatic expansion in controlling tropical precipitation, helping explain modern-day observations of a semidiurnal rainfall pattern. Climate simulations suggest atmospheric tides in resonance with atmospheric waves on early Earth when days were shorter could have modified tropical convection patterns and warmed the planet despite a fainter Sun.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":null,"pages":null},"PeriodicalIF":15.7,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141475260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-28DOI: 10.1038/s41561-024-01481-7
Climate models and paleoclimate proxy records indicate that the absence of preserved eastern Mediterranean organic-rich layers preceding mid-Pliocene glaciation is linked to a pan-North African humid period caused by a more northerly African monsoon front relative to subsequent glacials. The vegetation expansion caused by this humid phase might have influenced early hominin dispersal.
{"title":"An extended pan-North African humid period within the warm Pliocene","authors":"","doi":"10.1038/s41561-024-01481-7","DOIUrl":"10.1038/s41561-024-01481-7","url":null,"abstract":"Climate models and paleoclimate proxy records indicate that the absence of preserved eastern Mediterranean organic-rich layers preceding mid-Pliocene glaciation is linked to a pan-North African humid period caused by a more northerly African monsoon front relative to subsequent glacials. The vegetation expansion caused by this humid phase might have influenced early hominin dispersal.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":null,"pages":null},"PeriodicalIF":15.7,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141462404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-27DOI: 10.1038/s41561-024-01445-x
Luke D. Trusel
Surface meltwater plays a key role in ice shelf stability, and consequently, Antarctica’s sea level contributions. New satellite observations suggest there is substantially more surface meltwater than previously thought, and models are underestimating it.
{"title":"Slushy surface of Antarctic ice shelves","authors":"Luke D. Trusel","doi":"10.1038/s41561-024-01445-x","DOIUrl":"10.1038/s41561-024-01445-x","url":null,"abstract":"Surface meltwater plays a key role in ice shelf stability, and consequently, Antarctica’s sea level contributions. New satellite observations suggest there is substantially more surface meltwater than previously thought, and models are underestimating it.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":null,"pages":null},"PeriodicalIF":15.7,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-27DOI: 10.1038/s41561-024-01466-6
Rebecca L. Dell, Ian C. Willis, Neil S. Arnold, Alison F. Banwell, Sophie de Roda Husman
Surface melting occurs across many of Antarctica’s ice shelves, mainly during the austral summer. The onset, duration, area and fate of surface melting varies spatially and temporally, and the resultant surface meltwater is stored as ponded water (lakes) or as slush (saturated firn or snow), with implications for ice-shelf hydrofracture, firn air content reduction, surface energy balance and thermal evolution. This study applies a machine-learning method to the entire Landsat 8 image catalogue to derive monthly records of slush and ponded water area across 57 ice shelves between 2013 and 2021. We find that slush and ponded water occupy roughly equal areas of Antarctica’s ice shelves in January, with inter-regional variations in partitioning. This suggests that studies that neglect slush may substantially underestimate the area of ice shelves covered by surface meltwater. Furthermore, we found that adjusting the surface albedo in a regional climate model to account for the lower albedo of surface meltwater resulted in 2.8 times greater snowmelt across five representative ice shelves. This extra melt is currently unaccounted for in regional climate models, which may lead to underestimates in projections of ice-sheet melting and ice-shelf stability. Analysis of satellite imagery suggests that slush accounts for approximately half of the total meltwater area across Antarctic ice shelves.
{"title":"Substantial contribution of slush to meltwater area across Antarctic ice shelves","authors":"Rebecca L. Dell, Ian C. Willis, Neil S. Arnold, Alison F. Banwell, Sophie de Roda Husman","doi":"10.1038/s41561-024-01466-6","DOIUrl":"10.1038/s41561-024-01466-6","url":null,"abstract":"Surface melting occurs across many of Antarctica’s ice shelves, mainly during the austral summer. The onset, duration, area and fate of surface melting varies spatially and temporally, and the resultant surface meltwater is stored as ponded water (lakes) or as slush (saturated firn or snow), with implications for ice-shelf hydrofracture, firn air content reduction, surface energy balance and thermal evolution. This study applies a machine-learning method to the entire Landsat 8 image catalogue to derive monthly records of slush and ponded water area across 57 ice shelves between 2013 and 2021. We find that slush and ponded water occupy roughly equal areas of Antarctica’s ice shelves in January, with inter-regional variations in partitioning. This suggests that studies that neglect slush may substantially underestimate the area of ice shelves covered by surface meltwater. Furthermore, we found that adjusting the surface albedo in a regional climate model to account for the lower albedo of surface meltwater resulted in 2.8 times greater snowmelt across five representative ice shelves. This extra melt is currently unaccounted for in regional climate models, which may lead to underestimates in projections of ice-sheet melting and ice-shelf stability. Analysis of satellite imagery suggests that slush accounts for approximately half of the total meltwater area across Antarctic ice shelves.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":null,"pages":null},"PeriodicalIF":15.7,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01466-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141461950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-25DOI: 10.1038/s41561-024-01474-6
Francesca Remitti, Andrea Festa, Giuseppe Nirta, Edoardo Barbero, Silvia Mittempergher
The sources of shallow slow earthquakes at subduction zone fronts remain unclear, but are commonly attributed to faults and shear zones. Structural studies of modern and ancient shallow accretionary prisms — wedge-shaped stacks of sediments and volcanic deposits scraped from subducting slabs and accreted onto the overriding plates at convergent plate boundaries — document a plethora of brittle structures associated with metres to plurikilometre-scale overturned and recumbent folds. These folds are the product of rock buckling and shearing at the front of subduction zones. At present, such structures are not commonly considered in models of the dynamics of accretionary wedges at the timescale of the seismic cycle, instead focusing on the role played by slip on major faults. Here we argue that fold-related brittle structures might also be associated with transient deformation events at elevated strain rates and in the presence of high fluid pressure. They have the potential to cause distributed microearthquake swarms occurring under low effective normal stress in accretionary prisms, and to affect the distribution of surficial displacement. Folding-related brittle deformation structures in accretionary wedges may contribute to shallow seismicity in subduction zones, according to a compilation of structural evidence.
{"title":"Role of folding-related deformation in the seismicity of shallow accretionary prisms","authors":"Francesca Remitti, Andrea Festa, Giuseppe Nirta, Edoardo Barbero, Silvia Mittempergher","doi":"10.1038/s41561-024-01474-6","DOIUrl":"10.1038/s41561-024-01474-6","url":null,"abstract":"The sources of shallow slow earthquakes at subduction zone fronts remain unclear, but are commonly attributed to faults and shear zones. Structural studies of modern and ancient shallow accretionary prisms — wedge-shaped stacks of sediments and volcanic deposits scraped from subducting slabs and accreted onto the overriding plates at convergent plate boundaries — document a plethora of brittle structures associated with metres to plurikilometre-scale overturned and recumbent folds. These folds are the product of rock buckling and shearing at the front of subduction zones. At present, such structures are not commonly considered in models of the dynamics of accretionary wedges at the timescale of the seismic cycle, instead focusing on the role played by slip on major faults. Here we argue that fold-related brittle structures might also be associated with transient deformation events at elevated strain rates and in the presence of high fluid pressure. They have the potential to cause distributed microearthquake swarms occurring under low effective normal stress in accretionary prisms, and to affect the distribution of surficial displacement. Folding-related brittle deformation structures in accretionary wedges may contribute to shallow seismicity in subduction zones, according to a compilation of structural evidence.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":null,"pages":null},"PeriodicalIF":15.7,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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