Arc Crust-Magma Interaction  in the Andean Southern Volcanic Zone from Thermobarometry, Mineral Composition, Radiogenic Isotope and Rare Earth Element Systematics of the Azufre-Planchon-Peteroa Volcanic Complex, Chile

Holbik, Sven

doi:10.25148/etd.fi14071141

Cited by 2 publications

(3 citation statements)

References 97 publications

(239 reference statements)

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“…In Tormey [1989] and Tormey et al [1995] In Naranjo et al [1999] and Naranjo and Haller [2002] In in the post-collapse Planchón may also result from a higher accumulation of olivine, as previously reported for these samples [Tormey et al 1995;Holbik 2014]. Positive anomalies for K and Pb and negative Ti, Nb, and Ta are typically observed in arc magmas due to a metasomatized mantle wedge and Fe-Ti oxide fractionation (in the case of Ti).…”

Section: Stagesupporting

confidence: 64%

Rapid growth and catastrophic destruction events of Planchón Volcano, Southern Andes

Naranjo,

Romero,

Contreras

et al. 2024

Volcanica

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During the Late Pleistocene-to-Holocene, the mafic Planchón volcano (35.2 °S, Southern Andes) experienced two important destructive events: a sector collapse to the west and a multiphase explosive eruption transforming the east summit area. We provide new field and laboratory evidence, including geochemical, geochronologic, and geological-morphological analysis, to reconstruct the evolution, triggering mechanisms, and physical parameters of these events.The lateral collapse (48~ka BP) was mainly predisposed by a tectonically westward-inclined substratum and rapid edifice growth rates (0.3–0.48 km3 ka-1). The resulting Planchón-Teno debris avalanche became valley-confined traveling at c. 260 km h-1 up to 95 km distance and forming an 8.6 ± 1.3 km3 deposit. The resulting 4.1 km wide amphitheater was later destroyed at c. 7 ka BP by the multiphase Valenzuela phreatomagmatic eruptions, forming a c. 2.5 km diameter caldera. The case of the Planchón volcano warns that rapidly growing mafic volcanoes imply a substantial catastrophic hazard increase for the surrounding areas.

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Section: Stagesupporting

confidence: 64%

Rapid growth and catastrophic destruction events of Planchón Volcano, Southern Andes

Naranjo,

Romero,

Contreras

et al. 2024

Volcanica

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“…Mineral analyses were performed with the JEOL 8900 EPMA, Florida Center for Analytical Electron Microscopy, in the Department of Earth and Environment at Florida International University, using methods reported in Holbik (2014). Major and select trace elements (Ni, Cr, Co, V, Sc, Cu, Zn) were analyzed using the Jobin Yvon 70 ICP-OES in the FIU Department of Earth and Environment, using methods reported in Hickey-Vargas (1998).…”

Section: Sample Collection and Analytical Techniquesmentioning

confidence: 99%

“…Geochemical studies of temporal changes within individual stratovolcanoes, across-strike and along-strike comparisons have addressed and hypothesized which geochemical patterns are produced by crust, mantle, and subduction inputs (Lopez-Escobar et al, 1977;Deruelle et al, 1983;Hickey et al, 1986;Hildreth and Moorbath, 1988;Davidson et al, 1988;Hickey-Vargas et al, 1989;Sigmarsson et al, 1990;Morris et al, 1990;Tormey et al, 1991;Lopez-Escobar et al, 1995a;Dungan et al, 2001;Lara et al 2004;Reubi et al, 2011;Watt et al, 2013;Jacques et al, 2013;2014;Turner and Langmuir, 2015).…”

Section: Introductionmentioning

confidence: 99%

Geochemistry of basalts from small eruptive centers near Villarrica stratovolcano, Chile: Evidence for lithospheric mantle components in continental arc magmas

Hickey‐Vargas

Sun

Holbik

2016

Geochimica et Cosmochimica Acta

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In the Central Southern Volcanic Zone (CSVZ) of the Andes, the location of stratovolcanoes and monogenetic small eruptive centers (SEC) is controlled by the Liquiñe-Ofqui Fault Zone (LOFZ), a trench-parallel strike-slip feature of over 1000 km length. The geochemistry of basalts from SEC is different from those of stratovolcanoes, and are termed Type 2 and Type 1 basalts, respectively. In the region of Villarrica stratovolcano, contemporaneous SEC are more MgO-rich, and have greater light rare earth element (LREE) enrichment, lower 87 Sr/ 86 Sr and 143 Nd/ 144 Nd, and lower ratios of large ion lithophile elements (LILE) to LREE and high field strength elements (HFSE). A unique finding in this region is that basalts from one SEC, San Jorge, has Type 1 character, similar to basalts from Villarrica stratovolcano. Type 1 basalts from Villarrica and San Jorge SEC have strong signals from time-sensitive tracers of subduction input, such as high 10 Be/ 9 Be and high (238 U/ 230 Th), while Type 2 SEC have low 10 Be/ 9 Be and (238 U/ 230 Th) near secular equilibrium. Based on new trace element, radiogenic isotope and mineral analyses, we propose that Type 1 basaltic magma erupted at San Jorge SEC and Villarrica stratovolcano forms by melting of the ambient actively subductionmodified asthenosphere, while Type 2 SEC incorporate melts of pyroxenite residing in the supra-subduction zone mantle lithosphere. This scenario is consistent with the close proximity of the volcanic features and their inferred depths of magma separation. The pyroxenite forms from arc magma produced during earlier episodes of subduction modification and magmatism, which extend back >300 Ma along this segment of the western South American margin. Type 2 basaltic magmas may reach the surface during LOFZ-related decompression events, and they may also be a normal but episodic part of the magma supply to large stratovolcanoes, resulting in cryptic geochemical variations over time. The presence and mobilization of stored and aged subduction-related pyroxenite in the mantle lithosphere complicates the identification of subducted, mantle and crustal inputs to magma erupted in continental arcs.

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Arc Crust-Magma Interaction in the Andean Southern Volcanic Zone from Thermobarometry, Mineral Composition, Radiogenic Isotope and Rare Earth Element Systematics of the Azufre-Planchon-Peteroa Volcanic Complex, Chile

Cited by 2 publications

References 97 publications

Rapid growth and catastrophic destruction events of Planchón Volcano, Southern Andes

Rapid growth and catastrophic destruction events of Planchón Volcano, Southern Andes

Geochemistry of basalts from small eruptive centers near Villarrica stratovolcano, Chile: Evidence for lithospheric mantle components in continental arc magmas

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