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Matthew A Coble - One of the best experts on this subject based on the ideXlab platform.
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post supereruption recovery at toba caldera
Nature Communications, 2017Co-Authors: Adonara E Mucek, Martin Danisik, Shanaka L De Silva, Axel K Schmitt, Indyo Pratomo, Matthew A CobleAbstract:Large calderas, or supervolcanoes, are sites of the most catastrophic and hazardous events on Earth, yet the temporal details of post-supereruption activity, or resurgence, remain largely unknown, limiting our ability to understand how supervolcanoes work and address their hazards. Toba Caldera, Indonesia, caused the greatest volcanic catastrophe of the last 100 kyr, climactically erupting ∼74 ka. Since the supereruption, Toba has been in a state of resurgence but its magmatic and uplift history has remained unclear. Here we reveal that new 14C, zircon U–Th crystallization and (U–Th)/He ages show resurgence commenced at 69.7±4.5 ka and continued until at least ∼2.7 ka, progressing westward across the caldera, as reflected by post-caldera effusive lava eruptions and uplifted lake sediment. The major Stratovolcano north of Toba, Sinabung, shows strong geochemical kinship with Toba, and zircons from recent eruption products suggest Toba’s climactic magma reservoir extends beneath Sinabung and is being tapped during eruptions. Toba Caldera in Indonesia had one of the largest volcanic eruptions over the last 100 kyr and has since undergone periods of resurgence. Here, the authors present zircon and sediment age data showing resurgence started after the climactic eruption and lasted until 2.7 ka, advancing west and south.
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post supereruption recovery at toba caldera
Nature Communications, 2017Co-Authors: Adonara E Mucek, Martin Danisik, Shanaka L De Silva, Axel K Schmitt, Indyo Pratomo, Matthew A CobleAbstract:Large calderas, or supervolcanoes, are sites of the most catastrophic and hazardous events on Earth, yet the temporal details of post-supereruption activity, or resurgence, remain largely unknown, limiting our ability to understand how supervolcanoes work and address their hazards. Toba Caldera, Indonesia, caused the greatest volcanic catastrophe of the last 100 kyr, climactically erupting ∼74 ka. Since the supereruption, Toba has been in a state of resurgence but its magmatic and uplift history has remained unclear. Here we reveal that new 14C, zircon U-Th crystallization and (U-Th)/He ages show resurgence commenced at 69.7±4.5 ka and continued until at least ∼2.7 ka, progressing westward across the caldera, as reflected by post-caldera effusive lava eruptions and uplifted lake sediment. The major Stratovolcano north of Toba, Sinabung, shows strong geochemical kinship with Toba, and zircons from recent eruption products suggest Toba's climactic magma reservoir extends beneath Sinabung and is being tapped during eruptions.
Lisa Tauxe - One of the best experts on this subject based on the ideXlab platform.
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patterns of magma flow in segmented silicic dikes at summer coon volcano colorado ams and thin section analysis
Earth and Planetary Science Letters, 2004Co-Authors: Michael P Poland, Jonathan H Fink, Lisa TauxeAbstract:Abstract A complex pattern of magma flow is found in two silicic dikes of a radial swarm at Summer Coon, an eroded Stratovolcano in southern Colorado. The two intrusions are broken into multiple segments that suggest vertical dike propagation. However, anisotropy of magnetic susceptibility (AMS) measurements and thin section observations suggest that magma flow was often subhorizontal and away from the center of the volcano. Segments that are proximal to the central intrusion are characterized by magma that flowed steeply upward at the proximal segment extremity, then laterally along the segment, and finally downward at the distal end of the segment. Magma flow in offset segment tips located far from the volcano center was subhorizontal towards the adjacent segment, implying lateral propagation of segment tips towards one another. This observation suggests relatively high driving pressure in distal dike segments, as supported by dike thickening with radial distance from the center of the volcano. The present study indicates that radial dike evolution at Stratovolcanoes is dominated by lateral flow of magma and dike segmentation is a poor magma flow indicator. A horizontally propagating radial dike has the potential to cause an eruption low on the flank of a composite cone, which poses a significant yet largely unrecognized hazard to population centers and infrastructure that may surround the volcano.
Stéphane Scaillet - One of the best experts on this subject based on the ideXlab platform.
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tephrochronology of the mont dore volcanic massif massif central france new 40ar 39ar constraints on the late pliocene and early pleistocene activity
Bulletin of Volcanology, 2014Co-Authors: Sebastien Nomade, Herve Guillou, Jeanfrancois Pastre, Pierre Nehlig, Vincent Scao, Stéphane ScailletAbstract:The Mont-Dore Massif (500 km2), the youngest Stratovolcano of the French Massif Central, consists of two volcanic edifices: the Guery and the Sancy. To improve our knowledge of the oldest explosive stages of the Mont-Dore Massif, we studied 40Ar/39Ar-dated (through single-grain laser and step-heating experiments) 11 pyroclastic units from the Guery Stratovolcano. We demonstrate that the explosive history of the Guery can be divided into four cycles of explosive eruption activity between 3.09 and 1.46 Ma (G.I to G.IV). We have also ascertained that deposits associated with the 3.1–3.0-Ma rhyolitic activity, which includes the 5-km3 “Grande Nappe” ignimbrite, are not recorded in the central part of the Mont-Dore Massif. All the pyroclastites found in the left bank of the Dordogne River belong to a later explosive phase (2.86–2.58 Ma, G.II) and were channelled down into valleys or topographic lows where they are currently nested. This later activity also gave rise to most of the volcanic products in the Perrier Plateau (30 km east of the Mont-Dore Massif); three quarters of the volcano-sedimentary sequence (up to 100 m thick) was emplaced within less than 20 ky, associated with several flank collapses in the northeastern part of the Guery. The age of the “Fournet flora” (2.69 ± 0.01 Ma) found within an ash bed belonging to G.II suggests that temperate forests already existed in the French Massif Central before the Pliocene/Pleistocene boundary. The Guery’s third explosive eruption activity cycle (G.III) lasted between 2.36 and 1.91 Ma. It encompassed the Guery Lake and Morangie pumice and ash deposits, as well as seven other important events recorded as centimetric ash beds some 60 to 100 km southeast of the Massif in the Velay region. We propose a general tephrochronology for the Mont-Dore Stratovolcano covering the last 3.1 My. This chronology is based on 44 40Ar/39Ar-dated events belonging to eight explosive eruption cycles each lasting between 100 and 200 ky. The occurrence of only one pumice deposit in the 800-ky period between 1.9 and 1.1 Ma suggests that volcanic explosive activity was strongly reduced or quiescent.
Sebastien Nomade - One of the best experts on this subject based on the ideXlab platform.
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The earliest securely dated hominin fossil in Italy and evidence of Acheulian occupation during glacial MIS 16 at Notarchirico (Venosa, Basilicata, Italy)
Journal of Quaternary Science, 2015Co-Authors: Alison Pereira, Sebastien Nomade, Vincent Scao, Pierre Voinchet, Jean-jacques Bahain, Christophe Falguères, Henri Garon, David Lefevre, Jean-paul Raynal, Marcello PipernoAbstract:The Early Middle Pleistocene site of Notarchirico (Basilicata, Italy) is a 7-m-thick fluvially emplaced sedimentary sequence rich in volcanic materials coming from the Monte Vulture Stratovolcano. This site consists of 11 archaeological layers, some of which have yielded handaxes. One femur attributed to Homo heidelbergensis was also recovered from an upper level. We present in this study new 40Ar/39Ar and electron spin resonance ages that delimit the time of occupation of Notarchirico to between 670 ± 4 ka (14 ka) and 614 ± 4 ka (12 ka), therefore spanning mainly the glacial Marine Isotope Stage 16. Handaxes found in archaeosurface F are now securely dated to between 670 ± 4 ka (14 ka) and 661 ± 4 ka (14 ka) and prove that hominid populations living in southern Italy used Acheulian technology as early as the beginning of this stage. Futhermore, we placed the age of the human femur between 661 ± 4 ka (14 ka) and 614± 4 ka (12 ka). This fossil is therefore the oldest Middle Pleistocene human fossil discovered in Italy so far. Thanks to this new chronological framework, Notarchirico is now a key site in our understanding of the Early Acheulian culture in Western Europe.
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tephrochronology of the mont dore volcanic massif massif central france new 40ar 39ar constraints on the late pliocene and early pleistocene activity
Bulletin of Volcanology, 2014Co-Authors: Sebastien Nomade, Herve Guillou, Jeanfrancois Pastre, Pierre Nehlig, Vincent Scao, Stéphane ScailletAbstract:The Mont-Dore Massif (500 km2), the youngest Stratovolcano of the French Massif Central, consists of two volcanic edifices: the Guery and the Sancy. To improve our knowledge of the oldest explosive stages of the Mont-Dore Massif, we studied 40Ar/39Ar-dated (through single-grain laser and step-heating experiments) 11 pyroclastic units from the Guery Stratovolcano. We demonstrate that the explosive history of the Guery can be divided into four cycles of explosive eruption activity between 3.09 and 1.46 Ma (G.I to G.IV). We have also ascertained that deposits associated with the 3.1–3.0-Ma rhyolitic activity, which includes the 5-km3 “Grande Nappe” ignimbrite, are not recorded in the central part of the Mont-Dore Massif. All the pyroclastites found in the left bank of the Dordogne River belong to a later explosive phase (2.86–2.58 Ma, G.II) and were channelled down into valleys or topographic lows where they are currently nested. This later activity also gave rise to most of the volcanic products in the Perrier Plateau (30 km east of the Mont-Dore Massif); three quarters of the volcano-sedimentary sequence (up to 100 m thick) was emplaced within less than 20 ky, associated with several flank collapses in the northeastern part of the Guery. The age of the “Fournet flora” (2.69 ± 0.01 Ma) found within an ash bed belonging to G.II suggests that temperate forests already existed in the French Massif Central before the Pliocene/Pleistocene boundary. The Guery’s third explosive eruption activity cycle (G.III) lasted between 2.36 and 1.91 Ma. It encompassed the Guery Lake and Morangie pumice and ash deposits, as well as seven other important events recorded as centimetric ash beds some 60 to 100 km southeast of the Massif in the Velay region. We propose a general tephrochronology for the Mont-Dore Stratovolcano covering the last 3.1 My. This chronology is based on 44 40Ar/39Ar-dated events belonging to eight explosive eruption cycles each lasting between 100 and 200 ky. The occurrence of only one pumice deposit in the 800-ky period between 1.9 and 1.1 Ma suggests that volcanic explosive activity was strongly reduced or quiescent.
Adonara E Mucek - One of the best experts on this subject based on the ideXlab platform.
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post supereruption recovery at toba caldera
Nature Communications, 2017Co-Authors: Adonara E Mucek, Martin Danisik, Shanaka L De Silva, Axel K Schmitt, Indyo Pratomo, Matthew A CobleAbstract:Large calderas, or supervolcanoes, are sites of the most catastrophic and hazardous events on Earth, yet the temporal details of post-supereruption activity, or resurgence, remain largely unknown, limiting our ability to understand how supervolcanoes work and address their hazards. Toba Caldera, Indonesia, caused the greatest volcanic catastrophe of the last 100 kyr, climactically erupting ∼74 ka. Since the supereruption, Toba has been in a state of resurgence but its magmatic and uplift history has remained unclear. Here we reveal that new 14C, zircon U–Th crystallization and (U–Th)/He ages show resurgence commenced at 69.7±4.5 ka and continued until at least ∼2.7 ka, progressing westward across the caldera, as reflected by post-caldera effusive lava eruptions and uplifted lake sediment. The major Stratovolcano north of Toba, Sinabung, shows strong geochemical kinship with Toba, and zircons from recent eruption products suggest Toba’s climactic magma reservoir extends beneath Sinabung and is being tapped during eruptions. Toba Caldera in Indonesia had one of the largest volcanic eruptions over the last 100 kyr and has since undergone periods of resurgence. Here, the authors present zircon and sediment age data showing resurgence started after the climactic eruption and lasted until 2.7 ka, advancing west and south.
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post supereruption recovery at toba caldera
Nature Communications, 2017Co-Authors: Adonara E Mucek, Martin Danisik, Shanaka L De Silva, Axel K Schmitt, Indyo Pratomo, Matthew A CobleAbstract:Large calderas, or supervolcanoes, are sites of the most catastrophic and hazardous events on Earth, yet the temporal details of post-supereruption activity, or resurgence, remain largely unknown, limiting our ability to understand how supervolcanoes work and address their hazards. Toba Caldera, Indonesia, caused the greatest volcanic catastrophe of the last 100 kyr, climactically erupting ∼74 ka. Since the supereruption, Toba has been in a state of resurgence but its magmatic and uplift history has remained unclear. Here we reveal that new 14C, zircon U-Th crystallization and (U-Th)/He ages show resurgence commenced at 69.7±4.5 ka and continued until at least ∼2.7 ka, progressing westward across the caldera, as reflected by post-caldera effusive lava eruptions and uplifted lake sediment. The major Stratovolcano north of Toba, Sinabung, shows strong geochemical kinship with Toba, and zircons from recent eruption products suggest Toba's climactic magma reservoir extends beneath Sinabung and is being tapped during eruptions.