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Hugo Delgado-granados - One of the best experts on this subject based on the ideXlab platform.
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The eruptive history of the Tequila Volcanic field, western Mexico: ages, volumes, and relative proportions of lava types
Bulletin of Volcanology, 2005Co-Authors: Catherine B. Lewis-kenedi, Rebecca A. Lange, Chris M. Hall, Hugo Delgado-granadosAbstract:The eruptive history of the Tequila Volcanic field (1600 km^2) in the western Trans-Mexican Volcanic Belt is based on ^40Ar/^39Ar chronology and volume estimates for eruptive units younger than 1 Ma. Ages are reported for 49 Volcanic units, including Volcán Tequila (an andesitic stratovolcano) and peripheral domes, flows, and scoria cones. Volumes of Volcanic units ≤1 Ma were obtained with the aid of field mapping, ortho aerial photographs, digital elevation models (DEMs), and ArcGIS software. Between 1120 and 200 kyrs ago, a bimodal distribution of rhyolite (~35 km^3) and high-Ti basalt (~39 km^3) dominated the Volcanic field. Between 685 and 225 kyrs ago, less than 3 km^3 of andesite and dacite erupted from more than 15 isolated vents; these lavas are crystal-poor and show little evidence of storage in an upper crustal chamber. Approximately 200 kyr ago, ~31 km^3 of andesite erupted to form the stratocone of Volcán Tequila. The phenocryst assemblage of these lavas suggests storage within a chamber at ~2–3 km depth. After a hiatus of ~110 kyrs, ~15 km^3 of andesite erupted along the W and SE flanks of Volcán Tequila at ~90 ka, most likely from a second, discrete magma chamber located at ~5–6 km depth. The youngest Volcanic Feature (~60 ka) is the small andesitic volcano Cerro Tomasillo (~2 km^3). Over the last 1 Myr, a total of 128±22 km^3 of lava erupted in the Tequila Volcanic field, leading to an average eruption rate of ~0.13 km^3/kyr. This volume erupted over ~1600 km^2, leading to an average lava accumulation rate of ~8 cm/kyr. The relative proportions of lava types are ~22–43% basalt, ~0.4–1% basaltic andesite, ~29–54% andesite, ~2–3% dacite, and ~18–40% rhyolite. On the basis of eruptive sequence, proportions of lava types, phenocryst assemblages, textures, and chemical composition, the lavas do not reflect the differentiation of a single (or only a few) parental liquids in a long-lived magma chamber. The rhyolites are geochemically diverse and were likely formed by episodic partial melting of upper crustal rocks in response to emplacement of basalts. There are no examples of mingled rhyolitic and basaltic magmas. Whatever mechanism is invoked to explain the generation of andesite at the Tequila Volcanic field, it must be consistent with a dominantly bimodal distribution of high-Ti basalt and rhyolite for an 800 kyr interval beginning ~1 Ma, which abruptly switched to punctuated bursts of predominantly andesitic volcanism over the last 200 kyrs.
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The eruptive history of the Tequila Volcanic field, western Mexico: ages, volumes, and relative proportions of lava types
Bulletin of Volcanology, 2004Co-Authors: Catherine B. Lewis-kenedi, Rebecca A. Lange, Chris M. Hall, Hugo Delgado-granadosAbstract:The eruptive history of the Tequila Volcanic field (1600 km 2 ) in the western Trans-Mexican Volcanic Belt is based on 40 Ar/ 39 Ar chronology and volume esti- mates for eruptive units younger than 1 Ma. Ages are reported for 49 Volcanic units, including Volcn Tequila (an andesitic stratovolcano) and peripheral domes, flows, and scoria cones. Volumes of Volcanic units 1 Ma were obtained with the aid of field mapping, ortho aerial pho- tographs, digital elevation models (DEMs), and ArcGIS software. Between 1120 and 200 kyrs ago, a bimodal distribution of rhyolite (~35 km 3 ) and high-Ti basalt (~39 km 3 ) dominated the Volcanic field. Between 685 and 225 kyrs ago, less than 3 km 3 of andesite and dacite erupted from more than 15 isolated vents; these lavas are crystal-poor and show little evidence of storage in an upper crustal chamber. Approximately 200 kyr ago, ~31 km 3 of andesite erupted to form the stratocone of Volcn Tequila. The phenocryst assemblage of these la- vas suggests storage within a chamber at ~2-3 km depth. After a hiatus of ~110 kyrs, ~15 km 3 of andesite erupted along the W and SE flanks of Volcn Tequila at ~90 ka, most likely from a second, discrete magma chamber lo- cated at ~5-6 km depth. The youngest Volcanic Feature (~60 ka) is the small andesitic volcano Cerro Tomasillo (~2 km 3 ). Over the last 1 Myr, a total of 128€22 km 3 of
Catherine B. Lewis-kenedi - One of the best experts on this subject based on the ideXlab platform.
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The eruptive history of the Tequila Volcanic field, western Mexico: ages, volumes, and relative proportions of lava types
Bulletin of Volcanology, 2005Co-Authors: Catherine B. Lewis-kenedi, Rebecca A. Lange, Chris M. Hall, Hugo Delgado-granadosAbstract:The eruptive history of the Tequila Volcanic field (1600 km^2) in the western Trans-Mexican Volcanic Belt is based on ^40Ar/^39Ar chronology and volume estimates for eruptive units younger than 1 Ma. Ages are reported for 49 Volcanic units, including Volcán Tequila (an andesitic stratovolcano) and peripheral domes, flows, and scoria cones. Volumes of Volcanic units ≤1 Ma were obtained with the aid of field mapping, ortho aerial photographs, digital elevation models (DEMs), and ArcGIS software. Between 1120 and 200 kyrs ago, a bimodal distribution of rhyolite (~35 km^3) and high-Ti basalt (~39 km^3) dominated the Volcanic field. Between 685 and 225 kyrs ago, less than 3 km^3 of andesite and dacite erupted from more than 15 isolated vents; these lavas are crystal-poor and show little evidence of storage in an upper crustal chamber. Approximately 200 kyr ago, ~31 km^3 of andesite erupted to form the stratocone of Volcán Tequila. The phenocryst assemblage of these lavas suggests storage within a chamber at ~2–3 km depth. After a hiatus of ~110 kyrs, ~15 km^3 of andesite erupted along the W and SE flanks of Volcán Tequila at ~90 ka, most likely from a second, discrete magma chamber located at ~5–6 km depth. The youngest Volcanic Feature (~60 ka) is the small andesitic volcano Cerro Tomasillo (~2 km^3). Over the last 1 Myr, a total of 128±22 km^3 of lava erupted in the Tequila Volcanic field, leading to an average eruption rate of ~0.13 km^3/kyr. This volume erupted over ~1600 km^2, leading to an average lava accumulation rate of ~8 cm/kyr. The relative proportions of lava types are ~22–43% basalt, ~0.4–1% basaltic andesite, ~29–54% andesite, ~2–3% dacite, and ~18–40% rhyolite. On the basis of eruptive sequence, proportions of lava types, phenocryst assemblages, textures, and chemical composition, the lavas do not reflect the differentiation of a single (or only a few) parental liquids in a long-lived magma chamber. The rhyolites are geochemically diverse and were likely formed by episodic partial melting of upper crustal rocks in response to emplacement of basalts. There are no examples of mingled rhyolitic and basaltic magmas. Whatever mechanism is invoked to explain the generation of andesite at the Tequila Volcanic field, it must be consistent with a dominantly bimodal distribution of high-Ti basalt and rhyolite for an 800 kyr interval beginning ~1 Ma, which abruptly switched to punctuated bursts of predominantly andesitic volcanism over the last 200 kyrs.
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The eruptive history of the Tequila Volcanic field, western Mexico: ages, volumes, and relative proportions of lava types
Bulletin of Volcanology, 2004Co-Authors: Catherine B. Lewis-kenedi, Rebecca A. Lange, Chris M. Hall, Hugo Delgado-granadosAbstract:The eruptive history of the Tequila Volcanic field (1600 km 2 ) in the western Trans-Mexican Volcanic Belt is based on 40 Ar/ 39 Ar chronology and volume esti- mates for eruptive units younger than 1 Ma. Ages are reported for 49 Volcanic units, including Volcn Tequila (an andesitic stratovolcano) and peripheral domes, flows, and scoria cones. Volumes of Volcanic units 1 Ma were obtained with the aid of field mapping, ortho aerial pho- tographs, digital elevation models (DEMs), and ArcGIS software. Between 1120 and 200 kyrs ago, a bimodal distribution of rhyolite (~35 km 3 ) and high-Ti basalt (~39 km 3 ) dominated the Volcanic field. Between 685 and 225 kyrs ago, less than 3 km 3 of andesite and dacite erupted from more than 15 isolated vents; these lavas are crystal-poor and show little evidence of storage in an upper crustal chamber. Approximately 200 kyr ago, ~31 km 3 of andesite erupted to form the stratocone of Volcn Tequila. The phenocryst assemblage of these la- vas suggests storage within a chamber at ~2-3 km depth. After a hiatus of ~110 kyrs, ~15 km 3 of andesite erupted along the W and SE flanks of Volcn Tequila at ~90 ka, most likely from a second, discrete magma chamber lo- cated at ~5-6 km depth. The youngest Volcanic Feature (~60 ka) is the small andesitic volcano Cerro Tomasillo (~2 km 3 ). Over the last 1 Myr, a total of 128€22 km 3 of
Vivien Guyader - One of the best experts on this subject based on the ideXlab platform.
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continuous exhumation of mantle derived rocks at the southwest indian ridge for 11 million years
Nature Geoscience, 2013Co-Authors: Daniel Sauter, Mathilde Cannat, Stephane Roumejon, Muriel Andreani, Dominique Birot, A Bronner, Daniele Brunelli, Julie Carlut, Adelie Delacour, Vivien GuyaderAbstract:The global mid-ocean ridge system, where tectonic plates diverge, is traditionally thought of as the largest single Volcanic Feature on the Earth. Yet, wide expanses of smooth sea floor in the easternmost part of the Southwest Indian Ridge in the Indian Ocean lacks the hummocky morphology that is typical for submarine volcanism. At other slow-spreading ridges, the sea floor can extend by faulting the existing lithosphere, along only one side of the ridge axis. However, the smooth sea floor in the easternmost Southwest Indian Ridge also lacks the corrugated texture created by such faulting. Instead, the sea floor is smooth on both sides of the ridge axis and is thought to be composed of altered mantle-derived rocks. Here we use side-scan sonar to image the sea floor and dredge samples to analyse the composition of two sections of the Southwest Indian Ridge, between 62- 050 E and 64- 400 E, where the sea floor formed over the past 11 million years. We show that the smooth floor is almost entirely composed of seawater-altered mantle-derived rocks that were brought to the surface by large detachment faults on both sides of the ridge axis. Faulting accommodates almost 100% of plate divergence and the detachment faults have repeatedly flipped polarity.We suggest that this tectonic process could also explain the exhumation of mantle-derived rocks at the magma-poor margins of rifted continents.
Rebecca A. Lange - One of the best experts on this subject based on the ideXlab platform.
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The eruptive history of the Tequila Volcanic field, western Mexico: ages, volumes, and relative proportions of lava types
Bulletin of Volcanology, 2005Co-Authors: Catherine B. Lewis-kenedi, Rebecca A. Lange, Chris M. Hall, Hugo Delgado-granadosAbstract:The eruptive history of the Tequila Volcanic field (1600 km^2) in the western Trans-Mexican Volcanic Belt is based on ^40Ar/^39Ar chronology and volume estimates for eruptive units younger than 1 Ma. Ages are reported for 49 Volcanic units, including Volcán Tequila (an andesitic stratovolcano) and peripheral domes, flows, and scoria cones. Volumes of Volcanic units ≤1 Ma were obtained with the aid of field mapping, ortho aerial photographs, digital elevation models (DEMs), and ArcGIS software. Between 1120 and 200 kyrs ago, a bimodal distribution of rhyolite (~35 km^3) and high-Ti basalt (~39 km^3) dominated the Volcanic field. Between 685 and 225 kyrs ago, less than 3 km^3 of andesite and dacite erupted from more than 15 isolated vents; these lavas are crystal-poor and show little evidence of storage in an upper crustal chamber. Approximately 200 kyr ago, ~31 km^3 of andesite erupted to form the stratocone of Volcán Tequila. The phenocryst assemblage of these lavas suggests storage within a chamber at ~2–3 km depth. After a hiatus of ~110 kyrs, ~15 km^3 of andesite erupted along the W and SE flanks of Volcán Tequila at ~90 ka, most likely from a second, discrete magma chamber located at ~5–6 km depth. The youngest Volcanic Feature (~60 ka) is the small andesitic volcano Cerro Tomasillo (~2 km^3). Over the last 1 Myr, a total of 128±22 km^3 of lava erupted in the Tequila Volcanic field, leading to an average eruption rate of ~0.13 km^3/kyr. This volume erupted over ~1600 km^2, leading to an average lava accumulation rate of ~8 cm/kyr. The relative proportions of lava types are ~22–43% basalt, ~0.4–1% basaltic andesite, ~29–54% andesite, ~2–3% dacite, and ~18–40% rhyolite. On the basis of eruptive sequence, proportions of lava types, phenocryst assemblages, textures, and chemical composition, the lavas do not reflect the differentiation of a single (or only a few) parental liquids in a long-lived magma chamber. The rhyolites are geochemically diverse and were likely formed by episodic partial melting of upper crustal rocks in response to emplacement of basalts. There are no examples of mingled rhyolitic and basaltic magmas. Whatever mechanism is invoked to explain the generation of andesite at the Tequila Volcanic field, it must be consistent with a dominantly bimodal distribution of high-Ti basalt and rhyolite for an 800 kyr interval beginning ~1 Ma, which abruptly switched to punctuated bursts of predominantly andesitic volcanism over the last 200 kyrs.
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The eruptive history of the Tequila Volcanic field, western Mexico: ages, volumes, and relative proportions of lava types
Bulletin of Volcanology, 2004Co-Authors: Catherine B. Lewis-kenedi, Rebecca A. Lange, Chris M. Hall, Hugo Delgado-granadosAbstract:The eruptive history of the Tequila Volcanic field (1600 km 2 ) in the western Trans-Mexican Volcanic Belt is based on 40 Ar/ 39 Ar chronology and volume esti- mates for eruptive units younger than 1 Ma. Ages are reported for 49 Volcanic units, including Volcn Tequila (an andesitic stratovolcano) and peripheral domes, flows, and scoria cones. Volumes of Volcanic units 1 Ma were obtained with the aid of field mapping, ortho aerial pho- tographs, digital elevation models (DEMs), and ArcGIS software. Between 1120 and 200 kyrs ago, a bimodal distribution of rhyolite (~35 km 3 ) and high-Ti basalt (~39 km 3 ) dominated the Volcanic field. Between 685 and 225 kyrs ago, less than 3 km 3 of andesite and dacite erupted from more than 15 isolated vents; these lavas are crystal-poor and show little evidence of storage in an upper crustal chamber. Approximately 200 kyr ago, ~31 km 3 of andesite erupted to form the stratocone of Volcn Tequila. The phenocryst assemblage of these la- vas suggests storage within a chamber at ~2-3 km depth. After a hiatus of ~110 kyrs, ~15 km 3 of andesite erupted along the W and SE flanks of Volcn Tequila at ~90 ka, most likely from a second, discrete magma chamber lo- cated at ~5-6 km depth. The youngest Volcanic Feature (~60 ka) is the small andesitic volcano Cerro Tomasillo (~2 km 3 ). Over the last 1 Myr, a total of 128€22 km 3 of
Chris M. Hall - One of the best experts on this subject based on the ideXlab platform.
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The eruptive history of the Tequila Volcanic field, western Mexico: ages, volumes, and relative proportions of lava types
Bulletin of Volcanology, 2005Co-Authors: Catherine B. Lewis-kenedi, Rebecca A. Lange, Chris M. Hall, Hugo Delgado-granadosAbstract:The eruptive history of the Tequila Volcanic field (1600 km^2) in the western Trans-Mexican Volcanic Belt is based on ^40Ar/^39Ar chronology and volume estimates for eruptive units younger than 1 Ma. Ages are reported for 49 Volcanic units, including Volcán Tequila (an andesitic stratovolcano) and peripheral domes, flows, and scoria cones. Volumes of Volcanic units ≤1 Ma were obtained with the aid of field mapping, ortho aerial photographs, digital elevation models (DEMs), and ArcGIS software. Between 1120 and 200 kyrs ago, a bimodal distribution of rhyolite (~35 km^3) and high-Ti basalt (~39 km^3) dominated the Volcanic field. Between 685 and 225 kyrs ago, less than 3 km^3 of andesite and dacite erupted from more than 15 isolated vents; these lavas are crystal-poor and show little evidence of storage in an upper crustal chamber. Approximately 200 kyr ago, ~31 km^3 of andesite erupted to form the stratocone of Volcán Tequila. The phenocryst assemblage of these lavas suggests storage within a chamber at ~2–3 km depth. After a hiatus of ~110 kyrs, ~15 km^3 of andesite erupted along the W and SE flanks of Volcán Tequila at ~90 ka, most likely from a second, discrete magma chamber located at ~5–6 km depth. The youngest Volcanic Feature (~60 ka) is the small andesitic volcano Cerro Tomasillo (~2 km^3). Over the last 1 Myr, a total of 128±22 km^3 of lava erupted in the Tequila Volcanic field, leading to an average eruption rate of ~0.13 km^3/kyr. This volume erupted over ~1600 km^2, leading to an average lava accumulation rate of ~8 cm/kyr. The relative proportions of lava types are ~22–43% basalt, ~0.4–1% basaltic andesite, ~29–54% andesite, ~2–3% dacite, and ~18–40% rhyolite. On the basis of eruptive sequence, proportions of lava types, phenocryst assemblages, textures, and chemical composition, the lavas do not reflect the differentiation of a single (or only a few) parental liquids in a long-lived magma chamber. The rhyolites are geochemically diverse and were likely formed by episodic partial melting of upper crustal rocks in response to emplacement of basalts. There are no examples of mingled rhyolitic and basaltic magmas. Whatever mechanism is invoked to explain the generation of andesite at the Tequila Volcanic field, it must be consistent with a dominantly bimodal distribution of high-Ti basalt and rhyolite for an 800 kyr interval beginning ~1 Ma, which abruptly switched to punctuated bursts of predominantly andesitic volcanism over the last 200 kyrs.
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The eruptive history of the Tequila Volcanic field, western Mexico: ages, volumes, and relative proportions of lava types
Bulletin of Volcanology, 2004Co-Authors: Catherine B. Lewis-kenedi, Rebecca A. Lange, Chris M. Hall, Hugo Delgado-granadosAbstract:The eruptive history of the Tequila Volcanic field (1600 km 2 ) in the western Trans-Mexican Volcanic Belt is based on 40 Ar/ 39 Ar chronology and volume esti- mates for eruptive units younger than 1 Ma. Ages are reported for 49 Volcanic units, including Volcn Tequila (an andesitic stratovolcano) and peripheral domes, flows, and scoria cones. Volumes of Volcanic units 1 Ma were obtained with the aid of field mapping, ortho aerial pho- tographs, digital elevation models (DEMs), and ArcGIS software. Between 1120 and 200 kyrs ago, a bimodal distribution of rhyolite (~35 km 3 ) and high-Ti basalt (~39 km 3 ) dominated the Volcanic field. Between 685 and 225 kyrs ago, less than 3 km 3 of andesite and dacite erupted from more than 15 isolated vents; these lavas are crystal-poor and show little evidence of storage in an upper crustal chamber. Approximately 200 kyr ago, ~31 km 3 of andesite erupted to form the stratocone of Volcn Tequila. The phenocryst assemblage of these la- vas suggests storage within a chamber at ~2-3 km depth. After a hiatus of ~110 kyrs, ~15 km 3 of andesite erupted along the W and SE flanks of Volcn Tequila at ~90 ka, most likely from a second, discrete magma chamber lo- cated at ~5-6 km depth. The youngest Volcanic Feature (~60 ka) is the small andesitic volcano Cerro Tomasillo (~2 km 3 ). Over the last 1 Myr, a total of 128€22 km 3 of
