Episodic construction of batholiths: Insights from the spatiotemporal development of an ignimbrite flare-up

Silva, De; Gosnold, Will

doi:10.1016/j.jvolgeores.2007.07.015

Cited by 288 publications

(217 citation statements)

References 47 publications

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“…Here, we focus on the geological setting, the main structural elements including the resurgent dome and the caldera rim, and the caldera stratigraphy. La Pacana is the largest caldera of the Altiplano Puna Volcanic Complex of the central Andes (APVC), the largest Neogene ignimbrite f lare-up in the world, with an area of 30,000 km 2 (e.g., De Silva, 1989a, b;De Silva et al, 2006;De Silva and Gosnold, 2007). The APVC ignimbrite volumes are larger than 1,000 km 3 and their sources are several asymmetrical calderas that form huge depressions (e.g., De Silva and Gosnold, 2007), possibly with a tectonic control (Riller et al, 2001;.…”

Section: Geological Frameworkmentioning

confidence: 99%

“…La Pacana is the largest caldera of the Altiplano Puna Volcanic Complex of the central Andes (APVC), the largest Neogene ignimbrite f lare-up in the world, with an area of 30,000 km 2 (e.g., De Silva, 1989a, b;De Silva et al, 2006;De Silva and Gosnold, 2007). The APVC ignimbrite volumes are larger than 1,000 km 3 and their sources are several asymmetrical calderas that form huge depressions (e.g., De Silva and Gosnold, 2007), possibly with a tectonic control (Riller et al, 2001;. The APVC eruptive activity started 13 Ma ago (e.g., Schmitt et al, 2002) and occurred in short and intense eruptive pulses each ∼2-3 Ma (e.g., Salisbury et al, 2011).…”

Section: Geological Frameworkmentioning

confidence: 99%

“…The APVC eruptive activity started 13 Ma ago (e.g., Schmitt et al, 2002) and occurred in short and intense eruptive pulses each ∼2-3 Ma (e.g., Salisbury et al, 2011). However, 2 Ma ago the volcanic activity decreased in magnitude and the eruptive style shifted to smaller and more effusive eruptions (e.g., De Silva and Gosnold, 2007;Salisbury et al, 2011). At a much larger, whole crustal scale, the APVC structure has been studied from a geophysical point of view by seismic tomography and receiver functions (e.g., Chmielowski et al, 1999;Zandt et al, 2003;Ward et al, 2014), electromagnetic methods (Schilling et al, 2006;Comeau et al, 2015), and gravity (e.g., Götze and Krause, 2002;Tassara et al, 2006;Riller et al, 2006;Del Potro et al, 2013).…”

Section: Geological Frameworkmentioning

confidence: 99%

“…2). Due to the complexity of the caldera and the lack of dissection, the La Pacana collapse has been proposed to be produced by the eruptions of either Atana (4.11-4 Ma) (Gardeweg and Ramírez, 1987), Atana and Toconao (4.65 Ma) (Lindsay et al, 2001a,b;Schmitt et al, 2002), Pujsa (5.7 Ma) and Atana (Pavez et al, 2008) ignimbrites, or all of them (De Silva and Gosnold, 2007) (Fig. 2).…”

Section: Geological Frameworkmentioning

confidence: 99%

“…Due to the lack of observations of eruptions of this size, the caldera dynamics and the climatic impact of these supereruptions, including the effects over the human population, are poorly understood (e.g., Cole et al, 2005;Lipman, 1997;Self, 2006;Jones et al, 2007;Self and Blake, 2008). The largest ignimbrite f lareups in the world (e.g., Taupo volcanic zone, New Zealand; San Juan mountains, SW United States; Altiplano Puna Volcanic Complex APVC, southern central Andes of Bolivia, Chile and Argentina) are the places where the largest calderas in the world are located (Lipman, 2007;Rowland et al, 2010;De Silva, 1989a;De Silva et al, 2006;De Silva and Gosnold, 2007) and then constitute ideal study cases to investigate the dynamics of these supervolcanoes. The caldera inner structures are important in hazard assessment, as some of them show ground deformation likely related to magma intrusion (e.g., Wicks et al, 2006;Battaglia et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

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Nuevos antecedentes sobre la estructura interna de la caldera La Pacana mediante un estudio gravimétrico (Andes centrales, Chile).

Delgado

Pavez

2015

Andgeo

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ABSTRACT. La Pacana (central Andes, Northern Chile) is one of the largest resurgent calderas in the world, formed 4 Ma ago during an eruption with a VEI of 8.7. We undertake a gravimetric study to contribute new insights into the inner structure and evolution of this caldera. The La Pacana Bouguer residual anomaly is asymmetric and has an average amplitude of -12 to -14 mGal, which we interpret as being produced by the low-density intracaldera ignimbrite infill. A reinterpretation of the caldera stratigraphy plus the available geochronology suggests that the current shape of La Pacana was produced by the collapse of two nested calderas, roughly limited by the axis where the resurgent dome changes its orientation, with the oldest eruption in the southern part of La Pacana. The gravity data suggests that these southern and northern nested structures would have collapsed with downsag and trap-door geometries respectively, evidence of asymmetric subsidence. Intra caldera ignimbrite thicknesses were calculated with 2.5D forward models and show that the ignimbrite infill in its southern and northern parts reach ∼0.6-1.1 km and ∼2.5-3 km respectively. Using Gauss's theorem, we calculate the volume of the intra caldera ignimbrite infill is ∼3,400-3,500 km 3 , in agreement with previous estimates and with models that show that the larger the caldera diameter, the larger the erupted volume.Keywords: La Pacana caldera, Volcanology, Gravimetry, Caldera collapse.RESUMEN. Nuevos antecedentes sobre la estructura interna de la caldera La Pacana mediante un estudio gravimétrico (Andes centrales, Chile). La Pacana (Andes centrales, norte de Chile) es una de las calderas resurgentes más grandes del mundo, formada 4 Ma atrás en una erupción con un VEI de 8,7. Hemos realizado un estudio gravimétrico de la caldera para contribuir con nuevos antecedentes sobre su estructura interna y evolución. La anomalía residual de Bouguer de La Pacana es asimétrica y tiene una amplitud promedio de entre -12 a -14 mGal, la que se interpreta que es producida por el relleno de baja densidad de ignimbritas intracaldera. Una reinterpretación de la estratigrafía de la caldera junto con la geocronología disponible sugiere que la forma actual de La Pacana fue producida por el colapso de dos calderas anidadas, cuyo límite aproximado sería el eje donde el domo resurgente cambia su orientación, y con la erupción más antigua en la parte sur de La Pacana. Los datos gravimétricos sugieren que estas estructuras anidadas sur y norte habrían colapsado con geometrías de tipo downsag y trap-door respectivamente, evidencias de subsidencia asimétrica. Los espesores de las ignimbritas intracaldera fueron calculados con modelos directos en 2.5D los cuales muestran que el relleno en sus partes sur y norte alcanza a los ∼0,6-1,1 km y ∼2,5-3 km respectivamente. Mediante el teorema de Gauss, calculamos que el volumen de las ignimbritas intracaldera llega a los ∼3.400-3.500 km 3 , de acuerdo con estimaciones previas y con modelos que muestran que mientras más grande es el di...

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Section: Geological Frameworkmentioning

confidence: 99%

Section: Geological Frameworkmentioning

confidence: 99%

Section: Geological Frameworkmentioning

confidence: 99%

Section: Geological Frameworkmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nuevos antecedentes sobre la estructura interna de la caldera La Pacana mediante un estudio gravimétrico (Andes centrales, Chile).

Delgado

Pavez

2015

Andgeo

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Zircon U‐Pb geochronology of the Mount Givens Granodiorite: Implications for the genesis of large volumes of eruptible magma

Frazer

Coleman

Mills³

2014

JGR Solid Earth

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The Mount Givens Granodiorite, a large pluton in the central Sierra Nevada batholith, California, is similar in area to zoned intrusive suites yet is comparatively chemically and texturally homogenous. New zircon U-Pb geochronology indicates that the pluton was constructed over at least 7 Ma from 97.92 ± 0.06 Ma to 90.87 ± 0.05 Ma. Combining the new geochronology with the exposed volume of the pluton yields an estimated magma flux of <0.001 km 3 /a. The geochronologic data are at odds with the previously speculated links between plutons such as the Mount Givens Granodiorite and large-volume homogeneous ignimbrites (often termed monotonous intermediates). Existing data indicate that large plutons accumulate at rates of ≤0.001 km 3 /a, 1-2 orders of magnitude less than fluxes calculated for dated monotonous intermediates. If monotonous intermediates are remobilized, erupted plutons accumulated at rates comparable to dated examples, they should preserve a record of zircon growth of up to 10 Ma. Alternatively, the long history of zircon growth recorded in plutons may be erased during the processes of reheating and remobilization that precede supervolcano eruption. However, zircon dissolution modeling, based on hypothetical temperature-time histories for preeruptive monotonous intermediates, indicates that rejuvenation events would not sufficiently dissolve zircon. We suggest that eruptions of monotonous intermediates occur during high magmatic flux events, leaving little behind in the intrusive rock record, whereas low fluxes favor pluton accumulation.

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Persistent uplift of the Lazufre volcanic complex (Central Andes): New insights from PCAIM inversion of InSAR time series and GPS data

Rémy

Froger

Perfettini

et al. 2014

Geochem. Geophys. Geosyst.

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We reanalyzed the surface displacements observed at the Lazufre volcanic complex in the Southern Andean Central Volcanic Zone using GPS measurements made between 2006 and 2008 and a large InSAR data set. We performed a detailed spatiotemporal analysis of the displacements using a principal component analysis inversion method (PCAIM). The PCAIM reveals a source with no significant changes in shape and dimension and with a remarkably linear strength increase over the whole period of observation (i.e., [2003][2004][2005][2006][2007][2008][2009][2010]. Then we used a three-dimensional mixed boundary element method (MBEM) to invert the first component of surface displacement as obtained from PCAIM. We explored a continuum of geometries from a shallow elliptic crack to a deep massive truncated elliptical cone that could represent a sill or a large magma chamber, respectively. The best models indicate a large flat-topped source with a roof area between 40 and 670 km 2 and a depth of between 2 and 14 km below ground surface. Lastly, on the basis of the limited data available for the thermomechanical structure of the crust in the Southern Andean Central Volcanic Zone, we consider some possible scenarios to explain the spatial and temporal pattern of displacements at Lazufre.

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Episodic construction of batholiths: Insights from the spatiotemporal development of an ignimbrite flare-up

Cited by 288 publications

References 47 publications

Nuevos antecedentes sobre la estructura interna de la caldera La Pacana mediante un estudio gravimétrico (Andes centrales, Chile).

Nuevos antecedentes sobre la estructura interna de la caldera La Pacana mediante un estudio gravimétrico (Andes centrales, Chile).

Zircon U‐Pb geochronology of the Mount Givens Granodiorite: Implications for the genesis of large volumes of eruptible magma

Persistent uplift of the Lazufre volcanic complex (Central Andes): New insights from PCAIM inversion of InSAR time series and GPS data

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