Journal ArticleDOI
Partial assimilative recycling of the mafic plutonic roots of arc volcanoes: An example from the Chilean Andes
TLDR
The Tatara-San Pedro complex is characterized by xenocrysts and microxenoliths of olivine, augite, and plagioclase derived from solidified cumulates, wide but poorly correlated ranges of incompatible and compatible major and trace elements, and limited isotopic variability as discussed by the authors.Abstract:
At long-lived arc volcanic centers, open-system interactions between new magma and the plutonic roots of the arc will increase with time relative to interactions with older crust. Assimilative recycling of mafic plutonic arc roots will have different isotopic consequences than incorporation of aged continental crust. In the Tatara–San Pedro complex, 30 comagmatic basaltic lavas are characterized by xenocrysts and microxenoliths of olivine, augite, and plagioclase derived from solidified cumulates, wide but poorly correlated ranges of incompatible and compatible major and trace elements, and limited isotopic variability. This mineralogical-chemical signature reflects assimilation wherein grain-boundary melting and disaggregation of xenoliths led to blending of incompatible element– enriched melts derived mainly from hornblende, phlogopite, and plagioclase in combination with variable retention of xenocrysts, hence variable but high compatible element concentrations.read more
Citations
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Journal ArticleDOI
The Genesis of Intermediate and Silicic Magmas in Deep Crustal Hot Zones
TL;DR: In this article, a model for the generation of intermediate and silicic igneous rocks is presented, based on experimental data and numerical modeling, which is directed at subduction-related magmatism, but has general applicability to magmas generated in other plate tectonic settings, including continental rift zones.
Journal ArticleDOI
Amphibole “sponge” in arc crust?
TL;DR: In this article, amphibole is used as a filter for water dissolved in mantle-derived arc magmas, and amphibole cumulates may act as a fertile source of intracrustal melts and fluids.
Journal ArticleDOI
Vertically extensive and unstable magmatic systems: A unified view of igneous processes
TL;DR: The evidence that shallow magma chambers are actually assembled quickly from much larger, crystal-rich transcrustal magmatic systems is reviewed, infering that igneous processes differ substantially in the lower and upper crust.
Journal ArticleDOI
Oxygen Isotopes in Mantle and Crustal Magmas as Revealed by Single Crystal Analysis
TL;DR: MacPherson et al. as mentioned in this paper provided a review of several classic examples of silicic and basic magmatism, including Yellowstone and Iceland, that shows isotope zoning and heterogeneity reaching several permil.
Journal ArticleDOI
High-magnesian andesite from Mount Shasta: A product of magma mixing and contamination, not a primitive mantle melt
TL;DR: In this article, it has been shown that high-Mg andesites (HMAs) from the Mount Shasta area may represent near-primary mantle melts, carrying signatures of slab melt interaction with the Cascadia mantle wedge.
References
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Journal ArticleDOI
Trace element and isotopic effects of combined wallrock assimilation and fractional crystallization
TL;DR: In this paper, the mass assimilation rate is an arbitrary fraction(r) of the fractional crystallization rate, where r < 1 is a combination of zone refining and fractional scaling.
Journal ArticleDOI
Crustal contributions to arc magmatism in the Andes of Central Chile
Wes Hildreth,Stephen Moorbath +1 more
TL;DR: In this article, 15 andesite-dacite stratovolcanoes on the volcanic front of a single segment of the Andean arc show along-arc changes in isotopic and elemental ratios that demonstrate large crustal contributions to magma genesis.
Journal ArticleDOI
Cooling and contamination of mafic and ultramafic magmas during ascent through continental crust
TL;DR: In this article, the authors presented a model for cooling, crystallization and contamination during the turbulent ascent of a komatiite, a picritic basalt and a tholeiitic basalt.
Journal ArticleDOI
Crustal contamination versus subduction zone enrichment: Examples from the Lesser Antilles and implications for mantle source compositions of island arc volcanic rocks
TL;DR: Isotopic and geochemical data from the northern and central Lesser Antilles arc is presented in this paper, where a mixing model between MORB source and subducted sediment is tightly constrained in terms of the allowable proportion of sediment.
Journal ArticleDOI
Magma Mixing, Recharge and Eruption Histories Recorded in Plagioclase Phenocrysts from El Chichón Volcano, Mexico
TL;DR: In this article, increases in Sr concentrations in plagioclase phenocrysts of varying size (>1 cm to 2 mm) are reported from samples of the 1982 and pre-1982 (>200 ka) eruptions of El Chichon Volcano.
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Crustal contributions to arc magmatism in the Andes of Central Chile
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