Crystallization conditions and petrogenesis of the lava dome from the ∼900 years BP eruption of Cerro Machín Volcano, Colombia

Laeger, Kathrin; Halama, Ralf; Hansteen, Thor H.; Savov, Ivan P.; Murcia, Hugo; Cortés, Gloria Patricia; Garbe‐Schönberg, Dieter

doi:10.1016/j.jsames.2013.09.009

Cited by 32 publications

(53 citation statements)

References 82 publications

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“…Amphibole analyses were recalculated assuming 13 cations, excluding Ca, Na and K. The Fe 3+ /Fe 2+ are calculated based on charge balance assuming a charge of 46. Similar method has been applied by Laeger et al (2013). The results are presented in Table 3, the studied amphibole crystals are characterized by magnesium-rich with Mg 2+ /(Fe 2+ +Mg 2+ ) ratios ranging from 0.63 to 0.76 for the host rocks and 0.61 to 0.74 for the MMEs (Fig.…”

Section: Amphibolementioning

confidence: 89%

Mineral chemistry and crystallization conditions of the Late Cretaceous Mamba pluton from the eastern Gangdese, Southern Tibetan Plateau

Scheltens

et al. 2016

J. Earth Sci.

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The Late Cretaceous Mamba granodiorite belongs to a part of the Mesozoic Gangdese continental magmatic belt. No quantitative mineralogical study has been made hitherto, and hence the depth at which it formed is poorly constrained. Here we present mineralogical data for the Mamba pluton, including host rocks and their mafic microgranular enclaves (MMEs), to provide insights into their overall crystallization conditions and information about magma mixing. All amphiboles in the Mamba pluton are calcic, with B (Ca+Na)>1.5, and Si=6.81-7.42 apfu for the host rocks and Si=6.77-7.35 apfu for the MMEs. The paramount cation substitutions in amphibole include edenite type and tschermakite type. Biotites both in the host rocks and the MMEs collectively have high MgO (13.19 wt.%-13.03 wt.%) contents, but define a narrow range of Al apfu (atoms per formula unit) variations (2.44-2.57). The oxygen fugacity estimates are based on the biotite compositions cluster around the NNO buffer. The calculated pressure ranges from 1.2 to 2.1 kbar according to the aluminum-in-hornblende barometer. The computed pressure varies from 0.9 to 1.3 kbar based on the aluminum-in-biotite barometer which corresponds to an average depth of ca. 3.9 km. Besides, the estimates of crystallization pressures vary from 0.8 to 1.4 kbar based on the amphibole barometer proposed by Ridolfi et al. (2010), which can be equivalent to the depths ranging from 3.1 to 5.2 km. The MMEs have plagioclase oscillatory zonings and quartz aggregates, probably indicating the presence of magma mixing. Besides, core-to-rim element variations (Rb, Sr, Ba, and P) for the K-feldspar megacrysts serve as robust evidence to support magma mixing and crystal fractionation. This indicates the significance of the magma mixing that contributes to the formation of K-feldspar megacryst zonings in the Mamba pluton. KEY WORDS: Mamba pluton, Gangdese terrane, MMEs, K-feldspar megacrysts, magma mixing, P-T conditions, oxygen fugacity, in-situ trace element. INTRODUCTIONPrevious studies have demonstrated that the composition and structure of feldspar, biotite and amphibole in felsic rocks can serve as ideal proxies for physico-chemical conditions of magmas, such as crystallization and emplacement temperature, pressure, oxygen fugacity, water activity and compositional variations (Ayati et al.

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Section: Amphibolementioning

confidence: 89%

Mineral chemistry and crystallization conditions of the Late Cretaceous Mamba pluton from the eastern Gangdese, Southern Tibetan Plateau

Scheltens

et al. 2016

J. Earth Sci.

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“…We focused mainly on the amphibole thermobarometric formulations of Ridolfi et al (2010), because they can be applied to hybrid and re-homogenized magmas (e.g., Ridolfi et al 2010;Laeger et al 2013). All the studied rocks contain pargasites to magnesiohastingsites (Fig.…”

Section: P-t-x Conditionsmentioning

confidence: 99%

Petrogenesis of Miocene subvolcanic rocks in the Western Outer Carpathians (southeastern Moravia, Czech Republic)

Buriánek¹,

Kropáč²

2019

J. Geosci.

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Neogene subvolcanic rocks in southeastern Moravia form numerous dykes and laccoliths, ranging from clinopyroxene-amphibole and amphibole trachybasalt, through trachyandesite, to biotite-amphibole trachydacite. Leucocratic and melanocratic cumulate gabbro and basalt enclaves up to 70 cm in diameter are rarely present, respectively, within the trachydacite and trachyandesite. The parental magmas rose along tensional fissures spatially related to the Nezdenice Fault but probably never reached the surface. The range of major (e.g., SiO 2 44-62 wt. %, mg# 20-65) and trace-element compositions can be explained through magma mixing and mingling and subsequent fractional crystallization. Mineral chemistry shows limited compositional variation of mafic minerals. Diopside phenocrysts indicate narrow ranges of X Mg (0.65-0.84) and usually display normal zoning with small Mg-rich cores and Fe-rich rims. Phlogopites from the trachydacite and gabbro enclaves show a mutually similar composition (X Fe 0.36-0.43 and IV Al 2.44-2.59). Amphiboles from individual samples of basalt, trachybasalt and trachyandesite are likewise chemically relatively homogeneous (X Mg 0.51-0.86, Si 5.78-6.55). Chemical compositions of amphibole phenocrysts from the trachybasalts and trachyandesites indicate multi-stage crystallization at depth of 32 to 21 km for this magmatic system. Systematic changes in Si, Ti, VI Al, X Mg contents in amphiboles from trachydacites and gabbro enclaves can be explained by fractional crystallization in a shallower magma reservoir (~20-10 km).

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“…Gardner et al, 1996), lo que sugiere que ésta fue probablemente interrumpida durante el ascenso del magma, y que esto pudo haber sido causado por el encuentro del magma con un agente externo como un cuerpo de agua (Houghton y Wilson, 1989; Hiroi y Miyamoto, 2016). De esta manera, es posible sugerir que la erupción formadora del cráter actual de VCM estuvo fuertemente influenciada por la interacción agua/magma, proceso que impidió que el alto contenido de H 2 O en el magma (>5,7 wt.% si se consideran los valores reportados por Laeger et al, 2013) además de los otros volátiles, desarrollaran los procesos esperados de exsolución, nucleación, vesiculación y coalescencia (e.g. Cashman et al, 2000) y por ende, alta vesiculación en los fragmentos representativos del magma.…”

Section: Vesicularidad En Los Fragmentos Juveniles Y/o Accesoriosunclassified

Estratigrafía del cráter y morfología del volcán Cerro Machín, Colombia

et al. 2018

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RESUMEN El Volcán Cerro Machín (VCM) se localiza en el flanco oriental de la Cordillera Central de Colombia a 17 km al occidente de la ciudad de Ibagué (Tolima). El VCM es un volcán Holocénico de composición dacítica, con evidencia de grandes erupciones (VEI 5). Estratigráficamente, en las paredes internas del cráter es posible observar una secuencia de depósitos de Corrientes de Densidad Piroclástica (CDPs) diluida con características de depósitos de oleadas basales. La presencia de líticos accidentales evidencia que durante la fragmentación fue involucrado el basamento. De esta manera es posible sugerir que la interacción agua/magma jugó un papel importante en la dinámica del último evento eruptivo, el cual constituye los depósitos que conforman el cráter. Análisis morfológicos evidencian un cráter de 2,4 km de diámetro con una abertura hacia el sector suroccidental, el cual alberga un domo de 490 m de altura que posiblemente durante su emplazamiento fue el causante de la destrucción del cráter. Aunque el VCM es sin duda un volcán poligenético (seis erupciones en los últimos 5000 años), las características sedimentológicas de los depósitos del cráter así como su morfología, sugieren una estructura monogenética de cono de toba. En conclusión, el VCM debe ser definido como un "volcán compuesto con morfología de cono de toba". Palabras clave: Corrientes de Densidad Piroclástica (CDPs); oleadas piroclásticas; geomorfología volcánica; volcán poligenético; cono de toba.

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Crystallization conditions and petrogenesis of the lava dome from the ∼900 years BP eruption of Cerro Machín Volcano, Colombia

Cited by 32 publications

References 82 publications

Mineral chemistry and crystallization conditions of the Late Cretaceous Mamba pluton from the eastern Gangdese, Southern Tibetan Plateau

Mineral chemistry and crystallization conditions of the Late Cretaceous Mamba pluton from the eastern Gangdese, Southern Tibetan Plateau

Petrogenesis of Miocene subvolcanic rocks in the Western Outer Carpathians (southeastern Moravia, Czech Republic)

Estratigrafía del cráter y morfología del volcán Cerro Machín, Colombia

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