Nitrogen and trace elements in tektites and impact glasses

Abstract

Nitrogen and several trace elements have been studied in samples of one Muong Nong tektite, irghizites (tektite-like glass)/zhamanshinites (impactites) and several obsidian glasses. A detailed investigation of inter- and intra-layer samples from the Muong Nong tektite shows a chemical heterogeneity both within and between the layers. In general, the elemental variations seem to be due to a varying FeO content. Irghizites, both SiO₂-rich and SiO₂-poor, are compositionally more homogeneous than the zhamanshinites. The heterogeneous distribution of nitrogen, observed in the Muong Nong tektite and the zhamanshinites, is unlike that in any other tektite studied so far. This shows clearly that zhamanshinites have suffered lower peak temperatures than irghizites and Muong Nong tektites lower ones than normal "splash-form" tektites. Available chemical and petrological data on Muong Nong tektites suggest that they were formed by in situ melting of soil.