The nature and origin of Argentine loess

Abstract

Though the loess deposits of Argentina (Pampean Formation) are geologically well known, their granulometric and mineralogical composition has hitherto not been analyzed. The data obtained from a study of more than lifty samples are here summarized. It is shown that Argentine loess is similar in field appearance and texture to the North American and European loess. However, the mineralogical composition is completely different, especially in the coarse fractions where an assemblage of volcanic minerals is predominant. The presence of abundant montmorillonite and glass shards in the fine fraction is a point of resemblance between the Argentine and the American sediments. All this material, doubtless of volcanic-pyroclastic origin, has been transported by winds to the place of deposition.