Abstract

MUNOZ-SALINAS, Esperanza  and  CASTILLO-RODRIGUEZ, Miguel. Optically Stimulated Luminiscence applied to fluvial sediments: an approach based on the interpretation of luminous signals. Bol. Soc. Geol. Mex [online]. 2014, vol.66, n.2, pp.225-233. ISSN 1405-3322.

Fluvial deposits contain mineral grains that are exposed to solar radiation during their transport in the water column. Traditionally, the Optically Stimulated Luminescence (OSL) method has been used in geomorphology to date sediments that have been exposed to sunlight prior to their deposition. A new approach of OSL consists in using luminescence signals of sediments to unravel the mechanisms controlling sediment transport, regardless of whether or not the grains were fully exposed to sunlight before deposition. The main goal of this paper is to exemplify with two case studies on the use of luminescence signals to unravel how sediments are transported in two geomorphic domains. We studied the Sierra de Gredos (Spain) and the Cadder dam (Scotland) where we analyzed debris flow and fluvial deposits respectively. The luminescence signals in Sierra de Gredos allowed us to distinguish fluvial sediments from debris flow deposits. In Cadder we observed an inverse relation between grain size and the intensity of luminescence. We propose that the new approach of OSL in geomorphology is a useful tool in understanding the mechanisms of sediment transport in the study of fluvial sediments.

Keywords : Fluvial deposits; sediment transport; OSL; luminiscence signals; Sierra de Gredos; Cadder.