Petrology of the Younger Andesites and Dacites of Iztacc huatl Volcano, Mexico: I. Disequilibrium Phenocryst Assemblages as Indicators of Magma Chamber Processes

Nixon, Graham T.

doi:10.1093/petrology/29.2.213

Cited by 71 publications

(48 citation statements)

References 74 publications

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“…These studies showed as far back as in 1983 [22] for Los Humeros caldera, or in 1988 [182] for the MVB and in 1999 [24,26] for the Sierra de Chichinautzin in the C-MVB(f) that this volcanic province (MVB) is atypical and its origin can be best explained from the ongoing rifting or extensional processes rather than ongoing subduction. In fact, in one of my earlier papers [5] The presence of disequilibrium phenocryst assemblages is a common characteristics in several volcanoes of the C-MVB, which has been interpreted as mixing of magmas in crustal reservoirs [49,[187][188][189][190][191] and makes indispensable to take into account shallow-level processes before inferring about the deeper mantle and subduction processes. In fact, through the study of differentiated volcanic products of stratovolcanoes such as Iztaccíhuatl [49,187], Popocatépetl [59][60][61], or Nevado de Toluca [43], it would be almost impossible to unequivocally infer the deeper mantle processes, because the (continental) crustal processes can generally account for all observations, and there will be no objective way to separate the effects of processes taking place at shallower crustal depths from the deeper mantle.…”

Section: Geochemical Constraintsmentioning

confidence: 99%

Continental Rift Setting for the Central Part of the Mexican Volcanic Belt: A Statistical Approach

Verma¹

2009

TOGEOJ

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I prepared compilations of geochemical data from the central part of the Mexican Volcanic Belt (C-MVB), the Central American Volcanic Arc (CAVA) from Guatemala to northwestern Costa Rica, the continental arc of the Andes in South America, other mostly island arcs, extensional and continental break-up regions, and continental rifts. Using quantitative statistical methods, the origin of the C-MVB is constrained as a continental rift. Specifically, this continental rift setting for the C-MVB is inferred from conventional bivariate discrimination diagrams, new natural logarithmtransformed correct statistics-based discriminant function diagrams, quantitative Nb/Nb* parameter, and 99% confidence limits of the mean for the ratios of slab-or continental crust-sensitive and mantle-sensitive parameters. The subductionrelated models based on qualitative interpretations most commonly proposed for the Mexican Volcanic Belt in the literature are not supported from these robust quantitative constraints. All geological, structural, geochemical, isotopic (Sr, Nd, Pb, Os, and Be), and geophysical data are in fact consistent with this statistics-based conclusion of the continental rift setting and exclude involvement of the subducted slab from the genesis of the C-MVB magmas.

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Section: Geochemical Constraintsmentioning

confidence: 99%

Continental Rift Setting for the Central Part of the Mexican Volcanic Belt: A Statistical Approach

Verma¹

2009

TOGEOJ

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“…5B). These coronae generally occur a short distance away from the edge of the quartz crystal suggesting nucleation within the boundary layer melt (Nixon, 1988a).…”

Section: A B C D E Fmentioning

confidence: 99%

Mineralogical and geochemical evidence of magma mingling/mixing in the Sierra de las Cruces volcanic range, Mexican Volcanic Belt

Velasco-Tapia

Rodríguez-Saavedra

Márquez

et al. 2013

Journal of Iberian Geology

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Pliocene -Pleistocene lava flows, mainly of dacitic composition, are exposed in the Sierra de las Cruces (SC) volcanic range within the Mexican Volcanic Belt (MVB).SC volcanic rocks are porphyritic, generally containing an assemblage of plagioclase + amphibole + orthopyroxene ± clinopyroxene ± quartz ± Fe-Ti oxides. Most of them exhibit diverse mineralogical and geochemical features that attest a magma mixing and mingling processes with concomitant fractional crystallization in which a small volume of hot andesite magma injects into dacitic magma. Both rock types are probably derived from partial melting of continental crust at different levels.The evidences of magma mixing and mingling include: (a) normal and sieved plagioclases in the same sample, rounded and embayed crystals, and armoured rims over the dissolved crystal surfaces; (b) subrounded, vesicular magmatic enclaves, ranging from a few millimeters to ~20 centimeters in size, with plagioclase + orthopyroxene + amphibole + quartz ± olivine ± Fe-Ti-oxides assemblage; (c) mineral chemistry evidence such as crystals with reaction rims or heterogeneous plagioclase compositions (inverse and oscillatory zoning or normally and inversely zoned crystals) in the same sample; and (d) elemental geochemical variations and trace-element ratio more akin to magma mixing and to some extent diffusion process.These andesitic enclaves could be considered as portions of the intermediate magma that did not mix completely (mingling) with the felsic host lavas, confirming the major role of magma mixing and mingling processes in the overall evolution of the MVB 148

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“…En efecto, la gran mayoría de los investigadores han reconocido que la variedad petrológica de los estratovolcanes refl eja una suerte de mezcla entre distintos componentes magmáticos cuya residencia en cámaras magmáticas de larga duración permiten una efectiva homogeneización, y el consecuente emplazamiento de rocas volcánicas con composiciones relativamente monótonas (Nelson, 1980;Luhr y Carmichael, 1982;Nixon, 1988a;Nixon, 1988b;Robin et al, 1991;Straub y Martín-Del Pozzo, 2001;. Las evidencias más contundentes que demuestran la existencia de estas mezclas se ven fehacientemente plasmadas en la textura y mineralogía de los productos volcánicos.…”

Section: Estratovolcanesunclassified

“…Uno de los trabajos petrológicos más completos que documenta el proceso de mezcla fue el realizado por Nixon (1988aNixon ( , 1988b en el volcán Iztaccíhuatl (Izta). Nixon explica que la evolución petrológica del sistema magmático en el Izta está controlada por una vigorosa mezcla de magmas acompañada de un proceso de cristalización fraccionada.…”

Section: Estratovolcanesunclassified

Petrogénesis ígnea de la Faja Volcánica Transmexicana

Gómez-Tuena¹,

Orozco-Esquivel²,

Ferrari³

2005

BSGM

113

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C i e n A ñ o s ResumenLa extraordinaria diversidad magmática de la Faja Volcánica Transmexicana está controlada (directa o indirectamente) por dos placas oceánicas independientes cuyos parámetros geofísicos y composicionales se modifi can constantemente a lo largo de la trinchera, por un régimen tectónico esencialmente distensivo que opera con distinta intensidad sobre la placa continental, por un basamento cortical con diferentes edades, espesores y composiciones, y por una fuente mantélica primaria de composición extremadamente variable que ha sido infl uenciada, en mayor o menor medida, por los agentes químicos derivados de la subducción. El régimen tectónico convergente y, en consecuencia, el arco magmático, tampoco han evolucionado de forma homogénea a lo largo su historia, sino que han mostrado transformaciones notables en su posición, geometría y composición. Por estos motivos, la Faja Volcánica Transmexicana es el resultado de uno de los sistemas tectónicos convergentes más complejos del planeta, el objeto de más de un siglo de investigaciones científi cas, y también el centro de las controversias más notables sobre la geología mexicana.Palabras clave: Faja Volcánica Transmexicana, México, subducción, arco magmático, petrología ígnea, manto, corteza. Abstract The magmatic diversity of the Transmexican Volcanic Belt is directly or indirectly controlled by two independent oce-

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Petrology of the Younger Andesites and Dacites of Iztacc huatl Volcano, Mexico: I. Disequilibrium Phenocryst Assemblages as Indicators of Magma Chamber Processes

Cited by 71 publications

References 74 publications

Continental Rift Setting for the Central Part of the Mexican Volcanic Belt: A Statistical Approach

Continental Rift Setting for the Central Part of the Mexican Volcanic Belt: A Statistical Approach

Mineralogical and geochemical evidence of magma mingling/mixing in the Sierra de las Cruces volcanic range, Mexican Volcanic Belt

Petrogénesis ígnea de la Faja Volcánica Transmexicana

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