A supervolcano and its sidekicks: A 100 ka eruptive chronology of the Fish Canyon Tuff and associated units of the La Garita magmatic system
Establishing temporal constrains on major volcanic eruptions is limited by the precision of existing geochronometers. Prior work on the La Garita caldera, created by the eruption of the Fish Canyon Tuff, failed to resolve temporal differences between pre-, syn-, and post-collapse eruptive units. Here, we report 40Ar/39Ar geochronologic data supporting a ca. 100 ka eruptive history of the La Garita caldera, and resolving the timing of the precaldera Pagosa Peak Dacite , syncaldera Fish Canyon Tuff, and postcaldera Dacite of Nutras Creek. Minimizing uncertainty in neutron fluence by rotating samples during irradiation and employing Bayesian statistical interpretation of analytical data enables resolution of the ca. 60 ka precaldera eruptive history and a hiatus of 0 - 20 ka prior to the eruption of postcaldera lavas. The improved precision demonstrated using these methods provides previously unresolvable temporal constraints on physical processes in the La Garita magmatic system and underscores the potential of unraveling other closely-spaced events in geologic time.
Citation Information
| Publication Year | 2019 |
|---|---|
| Title | A supervolcano and its sidekicks: A 100 ka eruptive chronology of the Fish Canyon Tuff and associated units of the La Garita magmatic system |
| DOI | 10.1130/G45898.1 |
| Authors | Leah E. Morgan, Samuel Johnstone, Amy K. Gilmer, Michael A. Cosca, Ren A. Thompson |
| Publication Type | Article |
| Publication Subtype | Journal Article |
| Series Title | Geology |
| Index ID | 70204902 |
| Record Source | USGS Publications Warehouse |
| USGS Organization | Central Mineral and Environmental Resources Science Center; Geosciences and Environmental Change Science Center |
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Argon geochronology data for La Garita caldera
Leah E Morgan, Ph.D.
Research Geologist
Sam A Johnstone
Research Geologist
Amy Gilmer, PhD
Research Geologist
Michael Cosca
Research Geologist
Ren Thompson, PhD
Research Geologist
Related Content
- Data
Argon geochronology data for La Garita caldera
This dataset accompanies publication 'A supervolcano and its sidekicks: A 100 ka eruptive chronology of the Fish Canyon Tuff and associated units of the La Garita magmatic system', in review in Geology, which analyzed eruptive products from the La Garita caldera. - Connect
Leah E Morgan, Ph.D.
Research GeologistEmailPhoneSam A Johnstone
Research GeologistEmailPhoneAmy Gilmer, PhD
Research GeologistEmailPhoneMichael Cosca
Research GeologistEmailPhoneRen Thompson, PhD
Research GeologistEmailPhone