Rapid heterogeneous assembly of multiple magma reservoirs prior to Yellowstone supereruptions.

Jörn-Frederik Wotzlaw,Francois-Xavier D’Abzac,Urs Schaltegger,Richard A Stern,Ilya N Bindeman

doi:10.1038/srep14026

Jörn-Frederik Wotzlaw, Francois-Xavier D’Abzac + Show 3 more

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https://doi.org/10.1038/srep14026

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Abstract

Large-volume caldera-forming eruptions of silicic magmas are an important feature of continental volcanism. The timescales and mechanisms of assembly of the magma reservoirs that feed such eruptions as well as the durations and physical conditions of upper-crustal storage remain highly debated topics in volcanology. Here we explore a comprehensive data set of isotopic (O, Hf) and chemical proxies in precisely U-Pb dated zircon crystals from all caldera-forming eruptions of Yellowstone supervolcano. Analysed zircons record rapid assembly of multiple magma reservoirs by repeated injections of isotopically heterogeneous magma batches and short pre-eruption storage times of 103 to 104 years. Decoupled oxygen-hafnium isotope systematics suggest a complex source for these magmas involving variable amounts of differentiated mantle-derived melt, Archean crust and hydrothermally altered shallow-crustal rocks. These data demonstrate that complex magma reservoirs with multiple sub-chambers are a common feature of rift- and hotspot related supervolcanoes. The short duration of reservoir assembly documents rapid crustal remelting and two to three orders of magnitude higher magma production rates beneath Yellowstone compared to continental arc volcanoes. The short pre-eruption storage times further suggest that the detection of voluminous reservoirs of eruptible magma beneath active supervolcanoes may only be possible prior to an impending eruption.

Highlights

Large-volume caldera-forming eruptions of silicic magmas are an important feature of continental volcanism
Three major caldera forming eruptions are distinguished at Yellowstone and are represented by the ~2.1 Ma Huckleberry Ridge Tuff (HRT) with a total erupted volume of more than 2500 km[3], the ~1.3 Ma Mesa Falls Tuff (MFT, 280 km3), and the 0.62 Ma Lava Creek Tuff (LCT, ~1000 km3) that resulted in collapse of the Yellowstone caldera
We present a comprehensive data set including in situ oxygen isotope and trace element analyses, hafnium isotope analyses and high-precision U-Pb geochronology, all performed on the same crystals of accessory zircon from the three caldera forming eruptions at Yellowstone

Summary

Yellowstone supereruptions

Jörn-Frederik Wotzlaw[1,2], Ilya N. We present a comprehensive data set including in situ oxygen isotope and trace element analyses, hafnium isotope analyses and high-precision U-Pb geochronology, all performed on the same crystals of accessory zircon (see supplementary material for details) from the three caldera forming eruptions at Yellowstone. This data set provides a record of magma accumulation, magma sources, and pre-eruption evolution of the.

Results and Discussion

Median values of modeled data

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