Andesites of the 2009 eruption of Redoubt Volcano, Alaska

Coombs, Michelle L.; Sisson, T. W.; Bleick, Heather A.; Henton, S.; Nye, C. J.; Payne, A. L.; Cameron, Cheryl E.; Larsen, J. F.; Wallace, Kristi L.; Bull, K. F.

doi:10.1016/j.jvolgeores.2012.01.002

Cited by 65 publications

(53 citation statements)

References 59 publications

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“…5c,f) produce basalt-andesite hybrids in the lower crust (SiO 2 o55 wt%) and true andesites in the upper crust (56 wt%oSiO 2 o58 wt%). As a potential example, Redoubt volcano erupted silicic and mafic andesites, and the latter have been inferred to have been produced at greater depths than those more silicic 51 . It is also remarkable that most hybrids issued from basalt-felsic mixing cluster around 55 wt% SiO 2 , regardless of which felsic end-member (dacite or rhyolite) is being mixed-in.…”

Section: Resultsmentioning

confidence: 99%

On the conditions of magma mixing and its bearing on andesite production in the crust

et al. 2014

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Mixing between magmas is thought to affect a variety of processes, from the growth of continental crust to the triggering of volcanic eruptions, but its thermophysical viability remains unclear. Here, by using high-pressure mixing experiments and thermal calculations, we show that hybridization during single-intrusive events requires injection of high proportions of the replenishing magma during short periods, producing magmas with 55-58 wt% SiO 2 when the mafic end-member is basaltic. High strain rates and gas-rich conditions may produce more felsic hybrids. The incremental growth of crustal reservoirs limits the production of hybrids to the waning stage of pluton assembly and to small portions of it. Large-scale mixing appears to be more efficient at lower crustal conditions, but requires higher proportions of mafic melt, producing more mafic hybrids than in shallow reservoirs. Altogether, our results show that hybrid arc magmas correspond to periods of enhanced magma production at depth.

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Section: Resultsmentioning

confidence: 99%

On the conditions of magma mixing and its bearing on andesite production in the crust

et al. 2014

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“…However, these high-pressure estimates may be considered less reliable using the Ridolfi et al (2010) barometer as they could alternatively reflect strong compositional shifts or temperature changes with magma mixing (e.g. Coombs et al 2013;Erdmann et al 2014 (Fig. 12a).…”

Section: Pressurementioning

confidence: 99%

“…Recent studies have shown that caution must be taken when using Al concentrations in amphibole (Ridolfi et al 2010) as a proxy for crystallisation pressure alone (Coombs et al 2013;Shane and Smith 2013;Erdmann et al 2014). However, model pressures of 100-150 MPa from amphibole in units B and C match values from Oruanui HSR amphibole rims, which in turn are in agreement with volatile saturation pressures from Oruanui quartzhosted melt inclusions ( Fig.…”

Section: Establishment Of the (New?) Silicic Mush System From <17 Kamentioning

confidence: 99%

Fine-scale temporal recovery, reconstruction and evolution of a post-supereruption magmatic system

Barker

Wilson

Allan

et al. 2015

Contrib Mineral Petrol

214

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eruption of 25 rhyolitic units starting at ~12 ka. The dacites show strongly zoned minerals and wide variations in meltinclusion compositions, consistent with early magma mixing followed by periods of cooling and crystallisation at depths of >8 km, overlapping spatially with the inferred basal parts of the older Oruanui silicic mush system. The dacites reflect the first products of a new silicic system, as most of the Oruanui magmatic root zone was significantly modified in composition or effectively destroyed by influxes of hot mafic magmas following caldera collapse. The first rhyolites erupted between 12 and 10 ka formed through shallow (4-5 km depth) cooling and fractionation of melts from a source similar in composition to that generating the earlier dacites, with overlapping compositions for melt inclusions and crystal cores between the two magma types. For the successively younger rhyolite units, temporal changes in melt chemistry and mineral phase stability are observed, which reflect the development, stabilisation and maturation of a new, probably unitary, silicic mush system. This new mush system was closely linked to, and sometimes physically interacted with, underlying mafic melts of similar composition to those involved in the Oruanui supereruption. From the inferred depths of magma storage and geographical extent of vent sites, we consider that a large silicic mush system (>200 km 3 and possibly up to 1000 km 3 in volume) is now established at Taupo and is capable of feeding a new episode or cycle of volcanism at any stage in the future.

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“…Such magmas often display a bimodal distribution of amphibole compositions with a low-temperature population in equilibrium with the felsic host and a high-temperature population derived from the mafic recharge magma (Fig. 6; e.g., Coombs et al 2013;Kent 2014;Kiss et al 2014). Rare amphibole crystals in the HPRD (rhyo)dacites are resorbed and compositionally distinct from low-T amphibole but overlap with hightemperature compositions found in the enclaves, and thus appear to be derived from the mafic enclaves (Wyers and Barton 1989).…”

Section: Hprd Phenocryst Assemblagementioning

confidence: 99%

A mineral and cumulate perspective to magma differentiation at Nisyros volcano, Aegean arc

Klaver

Matveev

Berndt

et al. 2017

Contrib Mineral Petrol

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and these appear to be derived from the lower crust (0.5-0.8 GPa). The suppressed stability of plagioclase and early saturation of amphibole in these cumulates are indicative of high-pressure crystallisation from primitive hydrous melts (≥ 3 wt% H 2 O). Clinopyroxene in these cumulates has Al 2 O 3 contents up to 9 wt% due to the absence of crystallising plagioclase, and is subsequently consumed in a peritectic reaction to form primitive, Al-rich amphibole (Mg# > 73, 12-15 wt% Al 2 O 3 ). The composition of these peritectic amphiboles is distinct from trace element-enriched interstitial amphibole in shallower cumulates. Phenocryst compositions and assemblages in both suites differ markedly from the cumulates. Phenocrysts, therefore, reflect shallow crystallisation and do not record magma differentiation in the deep arc crust.

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Andesites of the 2009 eruption of Redoubt Volcano, Alaska

Cited by 65 publications

References 59 publications

On the conditions of magma mixing and its bearing on andesite production in the crust

On the conditions of magma mixing and its bearing on andesite production in the crust

Fine-scale temporal recovery, reconstruction and evolution of a post-supereruption magmatic system

A mineral and cumulate perspective to magma differentiation at Nisyros volcano, Aegean arc

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