Volcanic Episodes Near Yucca Mountain As Determined by Paleomagnetic Studies at Lathrop Wells, Crater Flat, and Sleeping Butte, Nevada

Champion, Duane E.; ,

Volcanic Episodes Near Yucca Mountain As Determined by Paleomagnetic Studies at Lathrop Wells, Crater Flat, and Sleeping Butte, Nevada

by Duane E. Champion, United States Geological Survey, Menlo Park, United States,

Document Type: Proceeding Paper

Part of: High Level Radioactive Waste Management 1991

Abstract:

It has been suggested that mafic volcanism in the vicinity of Yucca Mountain, Nev., is both recent (20 ka) and a product of complex 'polycyclic' eruptions. This pattern of volcanism, as interpreted by some workers at the Lathrop Wells volcanic complex, comprises a sequence of numerous small-volume eruptions that become more tephra-producing over time. Such sequences are thought to occur over timespans as long as 100,000 years. However, paleomagnetic studies of the tephra and lava flows from mafic volcanoes near Yucca Mountain fail to find evidence of repeated eruptive activity over timespans of 10³ to 10⁵ years, even though samples have been taken that represent approximately 95% of the products of these volcanoes. Instead, the eruptions seem to have occurred as discrete episodes at each center and thus can be considered to be 'monogenetic'. Dates of these episodes have been obtained by the proven radiometric-geochronometer methods of K-Ar or ⁴⁰Ar/³⁹Ar dating.

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