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Clinopyroxene is a common phenocryst phase in mafic to intermediate composition volcanic and plutonic rocks. It is highly resistant to alteration compared to other co-existing mafic phenocrysts such as plagioclase. Several recent studies have shown that clinopyroxene can be dated by 40Ar/39Ar using a new generation of multi-collector noble gas mass spectrometers. Thus far, 40Ar/39Ar dating of clinopyroxene phenocrysts has primarily been conducted on Neoproterozoic to Jurassic dolerites as well as mid-Cretaceous to Miocene submarine basalts. To assess the viability of 40Ar/39Ar dating clinopyroxene into the Neogene and Quaternary, incremental heating experiments were performed on tens of milligrams of clinopyroxene from a variety of mafic lithologies and tectonic settings younger than 34 Ma (subaerial arc basalts, gabbros, andesites, submarine basalts from mantle plumes). Most samples produced …