Origin of illites in the Luochuan loess section - Evidence from TEM study

Morphology and composition of illite from the Luochuan loess section were i nvestigated by TEM. The results show that most of the illite grains are cha racterized by rounded shapes and chemical compositions are closely similar to those of anchizonal illites. The enrichment of illites in paleosol over loess was mainly caused by the weak winter monsoon during the interglacial periods, and was not related to the in situ pedogenesis. Illite can serve a s an indicator for tracing eolian dust from Loess Plateau in pelagic and la custrine sediments.