Bottom sediments of Lake Peyungda as a natural archive of climatic and catastrophic events in the past

Abstract

Using scanning micro-XRF using synchrotron radiation, profiles of changes in the section depth of the elemental composition of the banded clays of Lake Peyungda (Krasnoyarsk region), located 33 km southwest of the epicenter of the Tunguska disaster of 1908, were obtained. The age model is confirmed by the presence of a dated layer of anomalous thickness associated with the fall and explosion of the Tunguska cosmic body (TCB). Changes in element contents in dated core layers are compared with instrumental meteorological observation data over the last century, and a relationship is found between the average annual temperature of the region and the elemental composition of coeval layers of bottom sediments (transfer function). According to scanning electron microscope and Raman spectroscopy, the 1908 layer is characterized by increased concentrations of Ti-containing minerals (anatase). The appearance of anatase is probably associated with the explosion of the TCB and the subsequent intense erosion of dolerite bodies, which are widely represented in the catchment area.