The Experts below are selected from a list of 171 Experts worldwide ranked by ideXlab platform
Alain Mangin - One of the best experts on this subject based on the ideXlab platform.
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The snake hiss: potential acoustic mimicry in a viper-colubrid complex
Biological Journal of the Linnean Society, 2014Co-Authors: Fabien Aubret, Alain ManginAbstract:Examples of acoustic Batesian mimicry are scarce, in contrast to visual mimicry. Here we describe a potential case of acoustic mimicry of a venomous viper model by harmless viperine snakes (colubrid). Viperine snakes resemble vipers in size, shape, colour, pattern, and anti-predatory behaviours, including Head Flattening, false strikes, and hissing. We sought to investigate whether hissing evolved as part of, or separately to, the viper mimic syndrome. To do this, we recorded and analysed the hissing sounds of several individual asp vipers, viperine snakes, and grass snakes (a close relative of viperine snakes that hisses but does not mimic the asp viper). Frequencies consistently ranged from 40 to 12 000 Hz across species and individuals. All vipers (100%) and most viperine snakes (84%) produced inhalation hissing sounds, in comparison to only 25% of grass snakes. Inhalation hissing sounds lasted longer in vipers than in viperine snakes. The hissing-sound composition of grass snakes differed significantly from that of both asp vipers and viperine snakes; however, the hissing-sound composition between viperine snakes and asp vipers was not statistically distinguishable. Whilst grass snake hissing sounds were characterized by high frequencies (5000–10 000 Hz), both vipers and viperine snake hissing sounds were dominated by low frequencies (200–400 Hz). A principal component analysis revealed no overlap between grass snakes and vipers, but important overlaps between viperine snakes and vipers, and between viperine snakes and grass snakes. The likelihood that these overlaps respectively reflect natural selection for Batesian mimicry and phylogeny constraints is discussed.
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the snake hiss potential acoustic mimicry in a viper colubrid complex
Biological Journal of The Linnean Society, 2014Co-Authors: Fabien Aubret, Alain ManginAbstract:Examples of acoustic Batesian mimicry are scarce, in contrast to visual mimicry. Here we describe a potential case of acoustic mimicry of a venomous viper model by harmless viperine snakes (colubrid). Viperine snakes resemble vipers in size, shape, colour, pattern, and anti-predatory behaviours, including Head Flattening, false strikes, and hissing. We sought to investigate whether hissing evolved as part of, or separately to, the viper mimic syndrome. To do this, we recorded and analysed the hissing sounds of several individual asp vipers, viperine snakes, and grass snakes (a close relative of viperine snakes that hisses but does not mimic the asp viper). Frequencies consistently ranged from 40 to 12 000 Hz across species and individuals. All vipers (100%) and most viperine snakes (84%) produced inhalation hissing sounds, in comparison to only 25% of grass snakes. Inhalation hissing sounds lasted longer in vipers than in viperine snakes. The hissing-sound composition of grass snakes differed significantly from that of both asp vipers and viperine snakes; however, the hissing-sound composition between viperine snakes and asp vipers was not statistically distinguishable. Whilst grass snake hissing sounds were characterized by high frequencies (5000–10 000 Hz), both vipers and viperine snake hissing sounds were dominated by low frequencies (200–400 Hz). A principal component analysis revealed no overlap between grass snakes and vipers, but important overlaps between viperine snakes and vipers, and between viperine snakes and grass snakes. The likelihood that these overlaps respectively reflect natural selection for Batesian mimicry and phylogeny constraints is discussed. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 1107–1114.
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The snake hiss: potential acoustic mimicry in a viper–colubrid complex
Biological Journal of The Linnean Society, 2014Co-Authors: Fabien Aubret, Alain ManginAbstract:Examples of acoustic Batesian mimicry are scarce, in contrast to visual mimicry. Here we describe a potential case of acoustic mimicry of a venomous viper model by harmless viperine snakes (colubrid). Viperine snakes resemble vipers in size, shape, colour, pattern, and anti-predatory behaviours, including Head Flattening, false strikes, and hissing. We sought to investigate whether hissing evolved as part of, or separately to, the viper mimic syndrome. To do this, we recorded and analysed the hissing sounds of several individual asp vipers, viperine snakes, and grass snakes (a close relative of viperine snakes that hisses but does not mimic the asp viper). Frequencies consistently ranged from 40 to 12 000 Hz across species and individuals. All vipers (100%) and most viperine snakes (84%) produced inhalation hissing sounds, in comparison to only 25% of grass snakes. Inhalation hissing sounds lasted longer in vipers than in viperine snakes. The hissing-sound composition of grass snakes differed significantly from that of both asp vipers and viperine snakes; however, the hissing-sound composition between viperine snakes and asp vipers was not statistically distinguishable. Whilst grass snake hissing sounds were characterized by high frequencies (5000–10 000 Hz), both vipers and viperine snake hissing sounds were dominated by low frequencies (200–400 Hz). A principal component analysis revealed no overlap between grass snakes and vipers, but important overlaps between viperine snakes and vipers, and between viperine snakes and grass snakes. The likelihood that these overlaps respectively reflect natural selection for Batesian mimicry and phylogeny constraints is discussed. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 1107–1114.
Evgenii Burov - One of the best experts on this subject based on the ideXlab platform.
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The plume Head-lithosphere interactions near intra-continental plate boundaries
Tectonophysics, 2007Co-Authors: Evgenii Burov, Elia D'acremont, Laurent Guillou-frottier, Laetitia Le Pourhiet, Sierd CloethingAbstract:Plume-lithosphere interactions (PLI) have important consequences both for tectonic and mineralogical evolution of the lithosphere: for example, Archean metallogenic crises at the boundaries of the West African and Australian cratons coincide with postulated plume events. In continents, PLI are often located near boundaries between younger plates (e.g., orogenic) and older stable plates (e.g., cratons), which represent important geometrical, thermal and rheological barriers that interact with the emplacement of the plume Head (e.g., Archean West Africa, East Africa, Pannonian – Carpathian system). The observable PLI signatures are conditioned by plume dynamics but also by lithosphere rheology and structure. We address the latter problem by considering a free-surface numerical model of PLI with two stratified elasto-viscous-plastic (EVP) lithospheric plates, one of which is older and thicker than another. The results show that: (1) plume Head Flattening is asymmetric, it is blocked from one side by the cold vertical boundary of the older plate, which leads to the mechanical decoupling of the crust from the mantle lithosphere, and to localized faulting at the cratonic margin; (2) the return flow from the plume Head results in sub-vertical down-thrusting (delamination) of the lithosphere at the margin, producing sharp vertical cold boundary down to the 400 km depth; (3) plume Head Flattening and migration towards the younger plate results in concurrent surface extension above the centre of the plume and in compression (pushing), down-thrusting and magmatic events at the cratonic margin (down-thrusting is also produced at the opposite border of the younger plate); these processes may result in continental growth at the “craton side”; (4) topographic signatures of PLI show basin-scale uplifts and subsidences preferentially located at cratonic margins. Negative Rayleigh-Taylor instabilities in the lithosphere above the plume Head provide a mechanism for crustal delamination. Inferred consequences of PLI near intra-continental plate boundaries, such as faulting at cratonic edges and enhanced magmatic activity, could explain plume-related metallogenic crises, as suggested for West Africa and Australia.
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The plume Head - lithosphere interactions near intracontinental plate boundaries
2006Co-Authors: Evgenii Burov, Laurent Guillou-frottierAbstract:Zones of plum-continental lithosphere interactions (PLI) are often located near intra-plate boundaries, in particular, near the boundaries between younger (e.g., orogenic) plates and older plates (Archean West Africa, Australian craton, Pannonian –Carpathian system). These interactions have important consequences both for tectonic and mineralogical evolution. For example, Archean metallogenic crisises at the boundaries of the West African and Australian cratons coincide with the presumed plum events. Yet, crustal and lithospheric signatures of PLI appear to be strongly influenced by lithosphere rheology and structure, which requires a through account for lithosphere in plum models. We study this problem using a numerical model that incorporates realistic visco-elasto-plastic stratified lithosphere with free a surface. The results show that lateral heterogeneities may have following effects on PLI: (A) horizontal plume Head Flattening is blocked from one side by cold vertical boundary of the craton, leading to crust – mantle decoupling, stress concentration andfaulting at the cratonic margin; (B) return flow from the plum Head results in subvertical down-thrusting of the lithosphere at the cratonic margin providing sharp subvertical “cold” boundaries down to the depths of 400 km; (C) the asymmetric plum Head Flattening towards the younger plate is followed by simultaneous extension and mantle thinning in the middle of the plate and down-thrusting both at the cratonic border and at the opposite border of the young plate; (D) topographic signatures of the PLI show basin-scale uplifts and subsidences. Rayleigh-Taylor instabilities that develop around the plume Head, provide a mechanism for crustal delamination. Lateral flow of mantle lithosphere, from plume Head to the base of the craton suggests a new mechanism for crustal growth, where surface magmatism is not required. Lithospheric faulting at cratonic edges and enhanced magmatic activity could explain the apparent plumerelated metallogenic crises, as suggested for West Africa and Australia. PLI can explain a number of key phenomena such as simultaneous occurrence of climax of extension of the young plates/segments and climax of compression in the surrounding belts.
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numerical modelling of a mantle plume the plume Head lithosphere interaction in the formation of an oceanic large igneous province
Earth and Planetary Science Letters, 2003Co-Authors: E Dacremont, S Leroy, Evgenii BurovAbstract:Abstract The thermomechanical processes associated with formation of large igneous provinces (LIPs) remain poorly understood owing to fundamental difficulties in simulating plume–lithosphere interactions in current numerical models. These models, which aim to simulate the rise of mantle plume and the spread of plume Head material, imply a mechanically over-simplified lithosphere and, commonly, a flat lithosphere (zero vertical displacement) as the upper boundary condition. We propose a new numerical model, derived from lithospheric-scale models. It has a high numerical resolution in the lithospheric domain and explicitly accounts for: (1) free upper surface boundary condition, (2) elastic–plastic–ductile lithospheric rheology, including surface faulting, and (3) vertical strength variations in the lithosphere. We study the final stages of plume ascent and we focus on surface and lithospheric evolution and intra-plate strain localisations. The experiments predict that the first surface elevation occurs in less than 0.2 Ma after plume initiation at 400 km depth. Variation of rheological parameters results in different surface elevations (500–2500 m), ascent (2–10 m/yr) and base plate strain rates (10−12–10−15 s−1). Fast (0.2–0.3 m/yr) plume Head Flattening starts at the moment when the plume Head reaches the base of the lithosphere. It leads to large-scale extension and deep normal faulting at the centre of the plateau, and to strong thermomechanical erosion at its base. The erosion is maximal not under the plume centre (as was predicted before), but in two large bordering zones. Our study locally is the igneous province of the Caribbean plate where the pre-existing (Farallon) lithosphere has been affected by the Galapagos hotspot activity that generated thermal perturbations and crustal thickening with two main episodes of volcanism and underplating.
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Numerical modelling of a mantle plume: the plume Head–lithosphere interaction in the formation of an oceanic large igneous province
Earth and Planetary Science Letters, 2003Co-Authors: Elia D'acremont, S Leroy, Evgenii BurovAbstract:Abstract The thermomechanical processes associated with formation of large igneous provinces (LIPs) remain poorly understood owing to fundamental difficulties in simulating plume–lithosphere interactions in current numerical models. These models, which aim to simulate the rise of mantle plume and the spread of plume Head material, imply a mechanically over-simplified lithosphere and, commonly, a flat lithosphere (zero vertical displacement) as the upper boundary condition. We propose a new numerical model, derived from lithospheric-scale models. It has a high numerical resolution in the lithospheric domain and explicitly accounts for: (1) free upper surface boundary condition, (2) elastic–plastic–ductile lithospheric rheology, including surface faulting, and (3) vertical strength variations in the lithosphere. We study the final stages of plume ascent and we focus on surface and lithospheric evolution and intra-plate strain localisations. The experiments predict that the first surface elevation occurs in less than 0.2 Ma after plume initiation at 400 km depth. Variation of rheological parameters results in different surface elevations (500–2500 m), ascent (2–10 m/yr) and base plate strain rates (10−12–10−15 s−1). Fast (0.2–0.3 m/yr) plume Head Flattening starts at the moment when the plume Head reaches the base of the lithosphere. It leads to large-scale extension and deep normal faulting at the centre of the plateau, and to strong thermomechanical erosion at its base. The erosion is maximal not under the plume centre (as was predicted before), but in two large bordering zones. Our study locally is the igneous province of the Caribbean plate where the pre-existing (Farallon) lithosphere has been affected by the Galapagos hotspot activity that generated thermal perturbations and crustal thickening with two main episodes of volcanism and underplating.
Fabien Aubret - One of the best experts on this subject based on the ideXlab platform.
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The snake hiss: potential acoustic mimicry in a viper-colubrid complex
Biological Journal of the Linnean Society, 2014Co-Authors: Fabien Aubret, Alain ManginAbstract:Examples of acoustic Batesian mimicry are scarce, in contrast to visual mimicry. Here we describe a potential case of acoustic mimicry of a venomous viper model by harmless viperine snakes (colubrid). Viperine snakes resemble vipers in size, shape, colour, pattern, and anti-predatory behaviours, including Head Flattening, false strikes, and hissing. We sought to investigate whether hissing evolved as part of, or separately to, the viper mimic syndrome. To do this, we recorded and analysed the hissing sounds of several individual asp vipers, viperine snakes, and grass snakes (a close relative of viperine snakes that hisses but does not mimic the asp viper). Frequencies consistently ranged from 40 to 12 000 Hz across species and individuals. All vipers (100%) and most viperine snakes (84%) produced inhalation hissing sounds, in comparison to only 25% of grass snakes. Inhalation hissing sounds lasted longer in vipers than in viperine snakes. The hissing-sound composition of grass snakes differed significantly from that of both asp vipers and viperine snakes; however, the hissing-sound composition between viperine snakes and asp vipers was not statistically distinguishable. Whilst grass snake hissing sounds were characterized by high frequencies (5000–10 000 Hz), both vipers and viperine snake hissing sounds were dominated by low frequencies (200–400 Hz). A principal component analysis revealed no overlap between grass snakes and vipers, but important overlaps between viperine snakes and vipers, and between viperine snakes and grass snakes. The likelihood that these overlaps respectively reflect natural selection for Batesian mimicry and phylogeny constraints is discussed.
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the snake hiss potential acoustic mimicry in a viper colubrid complex
Biological Journal of The Linnean Society, 2014Co-Authors: Fabien Aubret, Alain ManginAbstract:Examples of acoustic Batesian mimicry are scarce, in contrast to visual mimicry. Here we describe a potential case of acoustic mimicry of a venomous viper model by harmless viperine snakes (colubrid). Viperine snakes resemble vipers in size, shape, colour, pattern, and anti-predatory behaviours, including Head Flattening, false strikes, and hissing. We sought to investigate whether hissing evolved as part of, or separately to, the viper mimic syndrome. To do this, we recorded and analysed the hissing sounds of several individual asp vipers, viperine snakes, and grass snakes (a close relative of viperine snakes that hisses but does not mimic the asp viper). Frequencies consistently ranged from 40 to 12 000 Hz across species and individuals. All vipers (100%) and most viperine snakes (84%) produced inhalation hissing sounds, in comparison to only 25% of grass snakes. Inhalation hissing sounds lasted longer in vipers than in viperine snakes. The hissing-sound composition of grass snakes differed significantly from that of both asp vipers and viperine snakes; however, the hissing-sound composition between viperine snakes and asp vipers was not statistically distinguishable. Whilst grass snake hissing sounds were characterized by high frequencies (5000–10 000 Hz), both vipers and viperine snake hissing sounds were dominated by low frequencies (200–400 Hz). A principal component analysis revealed no overlap between grass snakes and vipers, but important overlaps between viperine snakes and vipers, and between viperine snakes and grass snakes. The likelihood that these overlaps respectively reflect natural selection for Batesian mimicry and phylogeny constraints is discussed. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 1107–1114.
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The snake hiss: potential acoustic mimicry in a viper–colubrid complex
Biological Journal of The Linnean Society, 2014Co-Authors: Fabien Aubret, Alain ManginAbstract:Examples of acoustic Batesian mimicry are scarce, in contrast to visual mimicry. Here we describe a potential case of acoustic mimicry of a venomous viper model by harmless viperine snakes (colubrid). Viperine snakes resemble vipers in size, shape, colour, pattern, and anti-predatory behaviours, including Head Flattening, false strikes, and hissing. We sought to investigate whether hissing evolved as part of, or separately to, the viper mimic syndrome. To do this, we recorded and analysed the hissing sounds of several individual asp vipers, viperine snakes, and grass snakes (a close relative of viperine snakes that hisses but does not mimic the asp viper). Frequencies consistently ranged from 40 to 12 000 Hz across species and individuals. All vipers (100%) and most viperine snakes (84%) produced inhalation hissing sounds, in comparison to only 25% of grass snakes. Inhalation hissing sounds lasted longer in vipers than in viperine snakes. The hissing-sound composition of grass snakes differed significantly from that of both asp vipers and viperine snakes; however, the hissing-sound composition between viperine snakes and asp vipers was not statistically distinguishable. Whilst grass snake hissing sounds were characterized by high frequencies (5000–10 000 Hz), both vipers and viperine snake hissing sounds were dominated by low frequencies (200–400 Hz). A principal component analysis revealed no overlap between grass snakes and vipers, but important overlaps between viperine snakes and vipers, and between viperine snakes and grass snakes. The likelihood that these overlaps respectively reflect natural selection for Batesian mimicry and phylogeny constraints is discussed. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 1107–1114.
Elia D'acremont - One of the best experts on this subject based on the ideXlab platform.
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Plume Head–lithosphere interactions near intra-continental plate boundaries
Tectonophysics, 2007Co-Authors: E Burov, Elia D'acremont, Laurent Guillou-frottier, Laetitia Le Pourhiet, S A P L CloetinghAbstract:Plume–lithosphere interactions (PLI) have important consequences both for tectonic and mineralogical evolution of the lithosphere: for example, Archean metallogenic crises at the boundaries of the West African and Australian cratons coincide with postulated plume events.Incontinents,PLIareoftenlocatednearboundariesbetweenyoungerplates(e.g.,orogenic)andolderstableplates(e.g.,cratons), which represent important geometrical, thermal and rheological barriers that interact with the emplacement of the plume Head (e.g., Archean West Africa, East Africa, Pannonian–Carpathian system). The observable PLI signatures are conditioned by plume dynamics but alsobylithosphere rheology and structure. We address the latterproblem by considering a free-surface numerical model ofPLI with two stratified elasto-viscous–plastic (EVP) lithospheric plates, one of which is older and thicker than another. The results show that: (1) plume Head Flattening is asymmetric, it is blocked from one side by the cold vertical boundary of the older plate, which leads to the mechanical decoupling of the crust from the mantle lithosphere, and to localized faulting at the cratonic margin; (2) the returnflow from the plume Head results in sub-vertical down-thrusting (delamination) of the lithosphere at the margin, producing sharp vertical cold boundary down to the 400 km depth; (3) plume Head Flattening and migration towards the younger plate results in concurrent surface extension above the centre of the plume and in compression (pushing), down-thrusting and magmatic events at the cratonic margin (down-thrusting is also produced at the opposite border of the younger plate); these processes may result in continental growth at the “craton side”; (4) topographic signatures of PLI show basin-scale uplifts and subsidences preferentially located at cratonic margins. Negative Rayleigh–Taylor instabilities in the lithosphere above the plume Head provide a mechanism for crustal delamination. Inferred consequences of PLI near intra-continental plate boundaries, such as faulting at cratonic edges and enhanced magmatic activity, could explain plume-related metallogenic crises, as suggested for West Africa and Australia. © 2007 Elsevier B.V. All rights reserved.
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The plume Head-lithosphere interactions near intra-continental plate boundaries
Tectonophysics, 2007Co-Authors: Evgenii Burov, Elia D'acremont, Laurent Guillou-frottier, Laetitia Le Pourhiet, Sierd CloethingAbstract:Plume-lithosphere interactions (PLI) have important consequences both for tectonic and mineralogical evolution of the lithosphere: for example, Archean metallogenic crises at the boundaries of the West African and Australian cratons coincide with postulated plume events. In continents, PLI are often located near boundaries between younger plates (e.g., orogenic) and older stable plates (e.g., cratons), which represent important geometrical, thermal and rheological barriers that interact with the emplacement of the plume Head (e.g., Archean West Africa, East Africa, Pannonian – Carpathian system). The observable PLI signatures are conditioned by plume dynamics but also by lithosphere rheology and structure. We address the latter problem by considering a free-surface numerical model of PLI with two stratified elasto-viscous-plastic (EVP) lithospheric plates, one of which is older and thicker than another. The results show that: (1) plume Head Flattening is asymmetric, it is blocked from one side by the cold vertical boundary of the older plate, which leads to the mechanical decoupling of the crust from the mantle lithosphere, and to localized faulting at the cratonic margin; (2) the return flow from the plume Head results in sub-vertical down-thrusting (delamination) of the lithosphere at the margin, producing sharp vertical cold boundary down to the 400 km depth; (3) plume Head Flattening and migration towards the younger plate results in concurrent surface extension above the centre of the plume and in compression (pushing), down-thrusting and magmatic events at the cratonic margin (down-thrusting is also produced at the opposite border of the younger plate); these processes may result in continental growth at the “craton side”; (4) topographic signatures of PLI show basin-scale uplifts and subsidences preferentially located at cratonic margins. Negative Rayleigh-Taylor instabilities in the lithosphere above the plume Head provide a mechanism for crustal delamination. Inferred consequences of PLI near intra-continental plate boundaries, such as faulting at cratonic edges and enhanced magmatic activity, could explain plume-related metallogenic crises, as suggested for West Africa and Australia.
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Numerical modelling of a mantle plume: the plume Head–lithosphere interaction in the formation of an oceanic large igneous province
Earth and Planetary Science Letters, 2003Co-Authors: Elia D'acremont, S Leroy, Evgenii BurovAbstract:Abstract The thermomechanical processes associated with formation of large igneous provinces (LIPs) remain poorly understood owing to fundamental difficulties in simulating plume–lithosphere interactions in current numerical models. These models, which aim to simulate the rise of mantle plume and the spread of plume Head material, imply a mechanically over-simplified lithosphere and, commonly, a flat lithosphere (zero vertical displacement) as the upper boundary condition. We propose a new numerical model, derived from lithospheric-scale models. It has a high numerical resolution in the lithospheric domain and explicitly accounts for: (1) free upper surface boundary condition, (2) elastic–plastic–ductile lithospheric rheology, including surface faulting, and (3) vertical strength variations in the lithosphere. We study the final stages of plume ascent and we focus on surface and lithospheric evolution and intra-plate strain localisations. The experiments predict that the first surface elevation occurs in less than 0.2 Ma after plume initiation at 400 km depth. Variation of rheological parameters results in different surface elevations (500–2500 m), ascent (2–10 m/yr) and base plate strain rates (10−12–10−15 s−1). Fast (0.2–0.3 m/yr) plume Head Flattening starts at the moment when the plume Head reaches the base of the lithosphere. It leads to large-scale extension and deep normal faulting at the centre of the plateau, and to strong thermomechanical erosion at its base. The erosion is maximal not under the plume centre (as was predicted before), but in two large bordering zones. Our study locally is the igneous province of the Caribbean plate where the pre-existing (Farallon) lithosphere has been affected by the Galapagos hotspot activity that generated thermal perturbations and crustal thickening with two main episodes of volcanism and underplating.
S A P L Cloetingh - One of the best experts on this subject based on the ideXlab platform.
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plume Head lithosphere interactions near intra continental plate boundaries
Tectonophysics, 2007Co-Authors: E Burov, Laetitia Le Pourhiet, Laurent Guilloufrottier, Elia Dacremont, S A P L CloetinghAbstract:Plume–lithosphere interactions (PLI) have important consequences both for tectonic and mineralogical evolution of the lithosphere: for example, Archean metallogenic crises at the boundaries of the West African and Australian cratons coincide with postulated plume events.Incontinents,PLIareoftenlocatednearboundariesbetweenyoungerplates(e.g.,orogenic)andolderstableplates(e.g.,cratons), which represent important geometrical, thermal and rheological barriers that interact with the emplacement of the plume Head (e.g., Archean West Africa, East Africa, Pannonian–Carpathian system). The observable PLI signatures are conditioned by plume dynamics but alsobylithosphere rheology and structure. We address the latterproblem by considering a free-surface numerical model ofPLI with two stratified elasto-viscous–plastic (EVP) lithospheric plates, one of which is older and thicker than another. The results show that: (1) plume Head Flattening is asymmetric, it is blocked from one side by the cold vertical boundary of the older plate, which leads to the mechanical decoupling of the crust from the mantle lithosphere, and to localized faulting at the cratonic margin; (2) the returnflow from the plume Head results in sub-vertical down-thrusting (delamination) of the lithosphere at the margin, producing sharp vertical cold boundary down to the 400 km depth; (3) plume Head Flattening and migration towards the younger plate results in concurrent surface extension above the centre of the plume and in compression (pushing), down-thrusting and magmatic events at the cratonic margin (down-thrusting is also produced at the opposite border of the younger plate); these processes may result in continental growth at the “craton side”; (4) topographic signatures of PLI show basin-scale uplifts and subsidences preferentially located at cratonic margins. Negative Rayleigh–Taylor instabilities in the lithosphere above the plume Head provide a mechanism for crustal delamination. Inferred consequences of PLI near intra-continental plate boundaries, such as faulting at cratonic edges and enhanced magmatic activity, could explain plume-related metallogenic crises, as suggested for West Africa and Australia. © 2007 Elsevier B.V. All rights reserved.
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Plume Head–lithosphere interactions near intra-continental plate boundaries
Tectonophysics, 2007Co-Authors: E Burov, Elia D'acremont, Laurent Guillou-frottier, Laetitia Le Pourhiet, S A P L CloetinghAbstract:Plume–lithosphere interactions (PLI) have important consequences both for tectonic and mineralogical evolution of the lithosphere: for example, Archean metallogenic crises at the boundaries of the West African and Australian cratons coincide with postulated plume events.Incontinents,PLIareoftenlocatednearboundariesbetweenyoungerplates(e.g.,orogenic)andolderstableplates(e.g.,cratons), which represent important geometrical, thermal and rheological barriers that interact with the emplacement of the plume Head (e.g., Archean West Africa, East Africa, Pannonian–Carpathian system). The observable PLI signatures are conditioned by plume dynamics but alsobylithosphere rheology and structure. We address the latterproblem by considering a free-surface numerical model ofPLI with two stratified elasto-viscous–plastic (EVP) lithospheric plates, one of which is older and thicker than another. The results show that: (1) plume Head Flattening is asymmetric, it is blocked from one side by the cold vertical boundary of the older plate, which leads to the mechanical decoupling of the crust from the mantle lithosphere, and to localized faulting at the cratonic margin; (2) the returnflow from the plume Head results in sub-vertical down-thrusting (delamination) of the lithosphere at the margin, producing sharp vertical cold boundary down to the 400 km depth; (3) plume Head Flattening and migration towards the younger plate results in concurrent surface extension above the centre of the plume and in compression (pushing), down-thrusting and magmatic events at the cratonic margin (down-thrusting is also produced at the opposite border of the younger plate); these processes may result in continental growth at the “craton side”; (4) topographic signatures of PLI show basin-scale uplifts and subsidences preferentially located at cratonic margins. Negative Rayleigh–Taylor instabilities in the lithosphere above the plume Head provide a mechanism for crustal delamination. Inferred consequences of PLI near intra-continental plate boundaries, such as faulting at cratonic edges and enhanced magmatic activity, could explain plume-related metallogenic crises, as suggested for West Africa and Australia. © 2007 Elsevier B.V. All rights reserved.
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Plume Head –lithosphere interactions near intra-continental plate boundaries
The EGU General Assembly, 2007Co-Authors: E Burov, Laurent Guillou-frottier, S A P L CloetinghAbstract:Zones of plum-continental lithosphere interactions (PLI) are often located near intra-plate boundaries, in particular, near the boundaries between younger (e.g., orogenic) plates and older plates (Archean West Africa, Australian craton, Pannonian –Carpathian system). These interactions have important consequences both for tectonic and mineralogical evolution. For example, Archean metallogenic crisises at the boundaries of the West African and Australian cratons coincide with the presumed plum events. Yet, crustal and lithospheric signatures of PLI appear to be strongly influenced by lithosphere rheology and structure, which requires a through account for lithosphere in plum models. We study this problem using a numerical model that incorporates realistic visco-elasto-plastic stratified lithosphere with free a surface. The results show that lateral heterogeneities may have following effects on PLI: (A) horizontal plume Head Flattening is blocked from one side by cold vertical boundary of the craton, leading to crust – mantle decoupling, stress concentration andfaulting at the cratonic margin; (B) return flow from the plum Head results in subvertical down-thrusting of the lithosphere at the cratonic margin providing sharp subvertical “cold” boundaries down to the depths of 400 km; (C) the asymmetric plum Head Flattening towards the younger plate is followed by simultaneous extension and mantle thinning in the middle of the plate and down-thrusting both at the cratonic border and at the opposite border of the young plate; (D) topographic signatures of the PLI show basin-scale uplifts and subsidences. Rayleigh-Taylor instabilities that develop around the plume Head, provide a mechanism for crustal delamination. Lateral flow of mantle lithosphere, from plume Head to the base of the craton suggests a new mechanism for crustal growth, where surface magmatism is not required. Lithospheric faulting at cratonic edges and enhanced magmatic activity could explain the apparent plumerelated metallogenic crises, as suggested for West Africa and Australia. PLI can explain a number of key phenomena such as simultaneous occurrence of climax of extension of the young plates/segments and climax of compression in the surrounding belts.
