Rhenium and osmium abundances in some igneous and metamorphic rocks

Abstract

Rhenium and osmium abundances in fourteen igneous and metamorphic rocks are reported. The values found range between 0.1 and 24 × 10−10 g/g Re and ⩽0.2 to 59 × 10−10 g/g Os.The two elements are inversely correlated and this is especially noticeable in a suite of four rocks (inclusions and basalt fragments) from a breccia pipe at Delegate, New South Wales.The highest osmium abundances are found in ultrabsic rocks but apart from this there is no systematic variation of abundance with rock type. Rhenium abundances in common surface igneous rocks are reasonably constant and a value of 5 ± 3 × 10−10 g/g Re is probably a close estimate of the abundance in the upper levels of the crust.