K-Ar dating of young volcanic rocks using peak comparison method

Abstract

The conventional K-Ar method assumes that the initial argon isotopic ratio is equal to the atmospheric ratio. Argon analyses of historical lavas (free in radiogenic argon) revealed that the initial isotopic ratios of rocks have experienced mass fractionation from the atmospheric argon isotopic ratio, requiring the peak comparison method for dating volcanic rocks. We analyzed using the peak comparison method; intra plate volcanic rocks from New Zealand, island arc volcanic rocks from Bali Island and dredge samples from deep-sea volcano in Mariana. The results give more reliable ages in comparison with the reported ages.