K-Ar dating on the alkaline rocks from Nemuro, Hokkaido

K-Ar and Ar-Ar Dating

The aim of this chapter is to present the K-Ar and Ar-Ar dating techniques in the context of noble gas studies, since there are already several recent texts on K-Ar and ArAr dating (Dickin 1995; McDougall and Harrison 1999). The focus of this section will be aspects of argon transport and storage in the crust, which affect K-Ar and Ar-Ar dating including Ar-loss from minerals by diffusion and A...

Alkaline Rocks and Geodynamics

105 Abstract: Origin of A-type alkali feldspar granites is currently the subject of a world-wide debate. Contrasting hypotheses have been proposed, which range from an entirely crustal origin to an almost complete mantle derivation. A-type alkali feldspar granites belong to either unimodal granite (rhyolite)-dominated association, or bimodal gabbro (basalt)-granite (rhyolite) suite. It is argue...

Dating species divergences using rocks and clocks.

Backstay and Irvine: Alkaline Volcanic Rocks from Gusev

Introduction: Study of the Martian crust by orbital spectroscopy and SNC meteorites has so far only recognized subalkaline volcanic rocks. However, Spirit rover measured high alkalis and low silica in picritic basalts on the Gusev plains [1,2], allowing the possibility that alkaline differentiates might occur. Isolated rocks having mildly alkaline compositions and distinctive spectra have now b...

Evaluation of the Ar/Ar Dating Process

During the last half of the twentieth century, the argon-argon method of dating geologic rocks and formations became very popular. This method replaced K/Ar as the method of choice for many types of rocks. This paper explores the fundamental mathematics of the argon-argon dating method and evaluates the impact of the assumed date of the “standard sample” on the calculated argon-argon date. A me...