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Revised age of the Rockland tephra, northern California: Implications for climate and stratigraphic reconstructions in the western United States: Comment

Andrei M. Sarna-Wojcicki
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Abstract

Lanphere et al. (1999) presented new data for the age of the Rockland pumice tuff breccia of Wilson (1961) using the incremental-heating 40 Ar/ 39 Ar technique. Their age, ∼610 ka, is ∼200 ka older than zircon fission-track ages obtained on this tuff by Meyer et al. (1980 ; 1991) . Application of new 40 Ar/ 39 Ar technologies to tephrochronometry is an important advance that allows more precise dating of widespread tephra layers. Although the new age may be correct, I urge caution in accepting it in place of grain-discrete fission-track dates and other data that suggest a younger age for this unit.

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90° N90° S · 180° W ← longitude → 180° E
Source-reported bounding extent: 40.029169344902755° to 40.58395362170714° latitude; -121.87446782508354° to -121.28438210623398° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Andrei M. Sarna-Wojcicki. 2000. Revised age of the Rockland tephra, northern California: Implications for climate and stratigraphic reconstructions in the western United States: Comment. https://doi.org/10.1130/0091-7613(2000)28%3C286%3Araotrt%3E2.0.co%3B2

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