The volcanic–plutonic connection as a stage for understanding crustal magmatism

Bachmann, Olivier; Miller, Calvin F.; Silva, De

doi:10.1016/j.jvolgeores.2007.08.002

Cited by 289 publications

(164 citation statements)

References 214 publications

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“…Richthofen stock is the origin of its chemical and isotopic heterogeneity. The Sr, Nd, and Pb isotopic variations in the stock preclude any simple closed system mechanism for producing these heterogeneities, including basaltic magma underplating, reheating, and partial melting of an antecedent intermediate composition stock or crystal mush (Bachmann et al 2007). Also, arguing for the importance of open-system processes in the formation of the Mt.…”

Section: Discussionmentioning

confidence: 99%

Deep crustal anatexis, magma mixing, and the generation of epizonal plutons in the Southern Rocky Mountains, Colorado

Jacob

Farmer

Buchwaldt

et al. 2015

Contrib Mineral Petrol

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differentiated versions of the silicic melts parental to the Mt. Cumulus stock. Zircon U-Pb geochronology further reveals that the Mt. Richthofen stock was incrementally emplaced over a time interval from at least 28.975 ± 0.020 to 28.742 ± 0.053 Ma. Magma mixing could have occurred either in situ in the upper crust during basaltic underplating and remelting of an antecedent, incrementally emplaced, silicic intrusive body, or at depth in the lower crust prior to periodic magma ascent and emplacement in the shallow crust. Overall, the two stocks demonstrate that magmatism associated with the Never Summer igneous complex was fundamentally bimodal in composition. Highly silicic anatectic melts of the mafic lower crust and basaltic, mantle-derived magmas were the primary melts in the magma system, with mixing of the two producing intermediate composition magmas such as those from which Mt. Richthofen stock was constructed.

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Section: Discussionmentioning

confidence: 99%

Deep crustal anatexis, magma mixing, and the generation of epizonal plutons in the Southern Rocky Mountains, Colorado

Jacob

Farmer

Buchwaldt

et al. 2015

Contrib Mineral Petrol

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“…Volcanic activity during arc flare-ups is dominated by the eruption of tens of thousands of cubic kilometers of ignimbrites ("ignimbrite flare-up") and by the formation of multiple spatially and temporally related caldera complexes. These collectively define the ignimbrite plateaus that are understood to be the surface expressions of incrementally constructed granodioritic to granitic batholiths (Lipman et al 1972;Bachmann et al 2007) and that are integral to the formation and stabilization of the continental crust. Closely associated with the magmatic history is a geomorphic evolution where erosion of the volcanic elements and exhumation of the plutonic roots leads to a sedimentary record that should, in principle, integrate the volcanic and plutonic records.…”

Section: Introductionmentioning

confidence: 99%

Quickening the Pulse: Fractal Tempos in Continental Arc Magmatism

2015

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“…Canonical models propose efficient liquid separation from a crystal mush (e.g., Bachmann and Bergantz 2004;Hildreth and Wilson 2007) in which granitoids reflect crystal cumulates from which the silicic melts have been largely removed before or during eruption (Bacon and Lowenstern 2005;Johnson et al 1989;Lipman 2007). Such models imply that associated with the generation of ignimbrite extrusions are significant volumes of subvolcanic magma that solidified as plutons that may be up to an order of magnitude larger than the erupted material (e.g., Bachmann et al 2007;Halliday et al 1989;Lipman 2007). The opposing views suggest that shallowly emplaced granitoids are often not the unerupted portion of volcanic rocks (Glazner et al 2008), that plutons accumulate incrementally Davis et al 2012), and that there are no long-lived magma chambers (e.g., Sparks et al 1990).…”

Section: Introductionmentioning

confidence: 99%

Assimilation of preexisting Pleistocene intrusions at Long Valley by periodic magma recharge accelerates rhyolite generation: rethinking the remelting model

Simon

Weis

DePaolo

et al. 2014

Contrib Mineral Petrol

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Rhyolite flows and tuffs from the Long Valley area of California, which were erupted over a two-millionyear time period, exhibit systematic trends in Nd, Hf, and Pb isotopes, trace element composition, erupted volume, and inferred magma residence time that provide evidence for a new model for the production of large volumes of silica-rich magma. Key constraints come from geochronology of zircon crystal populations combined with a refined eruption chronology from Ar-Ar geochronology; together these data give better estimates of magma residence time that can be evaluated in the context of changing magma compositions. Here, we report Hf, Nd, and Sr isotopes, major and trace element compositions, 40 Ar/ 39 Ar ages, and U-Pb zircon ages that combined with existing data suggest that the chronology and geochemistry of Long Valley rhyolites can be explained by a dynamic interaction of crustal and mantle-derived magma. The large volume Bishop Tuff represents the culmination of a period of increased mantle-derived magma input to the Long Valley volcanic system; the effect of this input continued into earliest postcaldera time. As the postcaldera evolution of the system continued, new and less primitive crustalderived magmas dominated the system. A mixture of varying amounts of more mafic mantle-derived and felsic crustal-derived magmas with recently crystallized granitic plutonic materials offers the best explanation for the observed chronology, secular shifts in Hf and Nd isotopes, and the apparently low zircon crystallization and saturation temperatures as compared to Fe-Ti oxide eruption temperatures. This scenario in which transient crustal magma bodies remained molten for varying time periods, fed eruptions before solidification, and were then remelted by fresh recharge provides a realistic conceptual framework that can explain the isotopic and geochemical evidence. General relationships between crustal residence times and magma sources are that: (1) precaldera rhyolites had long crustal magma residence times and high crustal affinity, (2) the caldera-related Bishop Tuff and early postcaldera rhyolites have lower crustal affinity and short magma residence times, and (3) later postcaldera rhyolites again have stronger crustal signatures and longer magma residence times.

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The volcanic–plutonic connection as a stage for understanding crustal magmatism

Cited by 289 publications

References 214 publications

Deep crustal anatexis, magma mixing, and the generation of epizonal plutons in the Southern Rocky Mountains, Colorado

Deep crustal anatexis, magma mixing, and the generation of epizonal plutons in the Southern Rocky Mountains, Colorado

Quickening the Pulse: Fractal Tempos in Continental Arc Magmatism

Assimilation of preexisting Pleistocene intrusions at Long Valley by periodic magma recharge accelerates rhyolite generation: rethinking the remelting model

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