Andrei M. Sarna-Wojcicki 2000 <p><a class="link link-ref link-reveal xref-bibr" data-open="I0091-7613-28-3-286-LANPHERE1">Lanphere et al. (1999)</a><span>&nbsp;presented new data for the age of the Rockland pumice tuff breccia of&nbsp;</span><a class="link link-ref link-reveal xref-bibr" data-open="I0091-7613-28-3-286-WILSON1">Wilson (1961)</a><span>&nbsp;using the incremental-heating&nbsp;</span>⁴⁰<span>Ar/</span>³⁹<span>Ar technique. Their age, ∼610 ka, is ∼200 ka older than zircon fission-track ages obtained on this tuff by&nbsp;</span><a class="link link-ref link-reveal xref-bibr" data-open="I0091-7613-28-3-286-MEYER1">Meyer et al. (1980</a><span>;&nbsp;</span><a class="link link-ref link-reveal xref-bibr" data-open="I0091-7613-28-3-286-MEYER2">1991)</a><span>. Application of new&nbsp;</span>⁴⁰<span>Ar/</span>³⁹<span>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.</span></p> application/pdf 10.1130/0091-7613(2000)28<286:RAOTRT>2.0.CO;2 en Geological Society of America Revised age of the Rockland tephra, northern California: Implications for climate and stratigraphic reconstructions in the western United States: Comment article