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| Titel |
Determining the physical processes behind four large eruptions in rapid
sequence in the San Juan caldera cluster (Colorado, USA) |
| VerfasserIn |
Adam Curry, Luca Caricchi, Peter Lipman |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250153630
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| Publikation (Nr.) |
 EGU/EGU2017-18630.pdf |
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| Zusammenfassung |
| Large, explosive volcanic eruptions can have both immediate and long-term negative effects
on human societies. Statistical analyses of volcanic eruptions show that the frequency of the
largest eruptions on Earth (> ∼450 km3) differs from that observed for smaller eruptions,
suggesting different physical processes leading to eruption. This project will characterize the
petrography, whole-rock geochemistry, mineral chemistry, and zircon geochronology of four
caldera-forming ignimbrites from the San Juan caldera cluster, Colorado, to determine the
physical processes leading to eruption. We collected outflow samples along stratigraphy of
the three caldera-forming ignimbrites of the San Luis caldera complex: the Nelson
Mountain Tuff (>500 km3), Cebolla Creek Tuff (∼250 km3), and Rat Creek Tuff
(∼150 km3); and we collected samples of both outflow and intracaldera facies
of the Snowshoe Mountain Tuff (>500 km3), which formed the Creede caldera.
Single-crystal sanidine 40Ar/39Ar ages show that these eruptions occurred in rapid
succession between 26.91 ± 0.02 Ma (Rat Creek) and 26.87 ± 0.02 Ma (Snowshoe
Mountain), providing a unique opportunity to investigate the physical processes
leading to a rapid sequence of large, explosive volcanic eruptions. Recent studies
show that the average flux of magma is an important parameter in determining the
frequency and magnitude of volcanic eruptions. High-precision isotope-dilution thermal
ionization mass spectrometry (ID-TIMS) zircon geochronology will be performed to
determine magma fluxes, and cross-correlation of chemical profiles in minerals will be
performed to determine the periodicity of magma recharge that preceded these
eruptions. Our project intends to combine these findings with similar data from
other volcanic regions around the world to identify physical processes controlling
the regional and global frequency-magnitude relationships of volcanic eruptions. |
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