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Full-Text Articles in Physical Sciences and Mathematics

Collaborative Research: A 700-Year Tephrochronology Of The Law Dome Ice Core, East Antarctica, Gregory A. Zielinski Jun 2006

Collaborative Research: A 700-Year Tephrochronology Of The Law Dome Ice Core, East Antarctica, Gregory A. Zielinski

University of Maine Office of Research Administration: Grant Reports

This award supports a project to analyze samples from the Law Dome ice core for volcanic tephra. The Law Dome ice core is the best-dated ice core from East Antarctica and contains a detailed record of climate and atmospheric chemistry over at least the last 700 years. Several global volcanic eruptions appear to be recorded in the Law Dome core, including the well known Tambora 1815 and Unknown 1809 events, as well as the Huaynaputina 1600 and Ruiz 1595 events. To verify the source eruptions responsible for these signals, as well as to differentiate between local Antarctic and southern hemisphere …


Long-Term Volumetric Eruption Rates And Magma Budgets, Scott M. White, Joy A. Crisp, Frank J. Spera Mar 2006

Long-Term Volumetric Eruption Rates And Magma Budgets, Scott M. White, Joy A. Crisp, Frank J. Spera

Faculty Publications

A global compilation of 170 time-averaged volumetric volcanic output rates (Qe) is evaluated in terms of composition and petrotectonic setting to advance the understanding of long-term rates of magma generation and eruption on Earth. Repose periods between successive eruptions at a given site and intrusive:extrusive ratios were compiled for selected volcanic centers where long-term (>104 years) data were available. More silicic compositions, rhyolites and andesites, have a more limited range of eruption rates than basalts. Even when high Qe values contributed by flood basalts (9 ± 2 10[1]1 km3/yr) are removed, there is a trend in decreasing average Qe …


Contrasting Silicic Magma Series In Miocene-Pliocene Ash Deposits In The San Miguel De Allende Graben, Guanajuato, Mexico, Eric H. Christiansen, Bart J. Kowallis, Aaron J. Adams, Oscar Carranza-Castaneda, Wade E. Miller Mar 2006

Contrasting Silicic Magma Series In Miocene-Pliocene Ash Deposits In The San Miguel De Allende Graben, Guanajuato, Mexico, Eric H. Christiansen, Bart J. Kowallis, Aaron J. Adams, Oscar Carranza-Castaneda, Wade E. Miller

Faculty Publications

The San Miguel de Allende graben, Guanajuato, Mexico, contains numerous rhyolitic volcanic ash beds. Electron microprobe and x-ray fluorescence analyses of glass shards from 14 localities, combined with mineralogic, stratigraphic, radiometric, and paleomagnetic data, allow us to correlate the ash beds (and the intervening sedimentary strata and fossils), understand the timing of volcanism, date the age of extension, and better understand the tectonic and volcanic evolution of central Mexico. Our analyses reveal that at least six separate eruptions of rhyolitic ash occurred during the Late Miocene and Pliocene (5-3 Ma) while the San Miguel Allende basin was subsiding. The fallout …