Noble gases and nitrogen in Muong Nong tektites

Abstract

Three samples of Muong Nong tektites have been studied for N and noble gases. The isotopic composition of noble gases is airlike. The noble gas amounts are much higher in Muong Nong tektites than in splash-form tektites. As compared to air, He and Ne have been enriched, most likely due to inward diffuion from ambient air, subsequent to glass formation. Nitrogen contents range from 0.3 to 1.34 ppm, with a non-atmospheric δ15N ranging from 8 to 17‰. The release pattern of δ15N clearly shows the presence of two N components. Higher N/36Ar values than those of air, together with positive δ15N, show that a major portion of N in Muong Nong tektites is a remnant from the sedimentary source material.