Interpreting luminescence data from a portable OSL reader: three case studies in fluvial settings

Abstract

Optically stimulated luminescence (OSL) is a technique that has been applied from the mid-1980s, mainly for sediment dating. The OSL technique is based on sample stimulation by light to determine the luminescence signal that is stored in the crystal lattices of sediment grains after deposition, burial by later sediment and subsequent exposure to ionizing radiation from radioactive elements in the surrounding sediment. In such sediment dating, two parameters are required: the equivalent dose (i.e. the luminescence signal stored in the grains), and the dose rate (i.e. the ionizing energy from a, b and g radiation emitted by naturally occurring radioisotopes in the deposit, plus the effects of cosmic radiation). In this research, the OSL technique is not used for dating. The study goal is to analyse only the luminescence signals (the total photon counts) in polymineral samples obtained after light stimulation in the blue (BLSL) and infrared (IRSL) wavelengths using a portable OSL reader designed and built at the Scottish Universities Environmental Research Centre (SUERC). Three fluvial case studies -from Cambodia, Australia and Mexico -are used to illustrate the geomorphological interpretations possible with the portable OSL reader data from sediments resulting from a range of different depositional processes. The case studies show that aspects of sediment's transport and depositional processes can be inferred from the portable OSL reader data, providing valuable insights into geomorphological history.

Instant luminescence chronologies? High resolution luminescence profiles using a portable luminescence reader

“…Munyigwa et al 2012, Figures 6 and 7) and, as with this study, have shown it is possible to identify stratigraphic breaks which are not necessarily discernible (e.g. Kinnard et al 2012;Muñoz-Salinas et al 2011). POSL profiling of very recent sediments, such as investigated in this study, appears to be successful and supports the findings of Muñoz-Salinas et al (2012) who successfully used PSOL data from deposits which were in the 10-500 year range.…”

“…As shown elsewhere (e.g. Sanderson et al 2003;Kinnaird et al 2011;Muñoz-Salinas et al 2011), where more varied sediment types are profiled then correction might be of more significance. Given the IR data are generated as part of the Post IR OSL then seeing whether this is the case does not detract from the principle of rapid on site profiling.…”

Sedimentological processes in lahars: Insights from optically stimulated luminescence analysis

“…3B and C) (Sanderson and Murphy, 2010); which has been successfully tested and used to elucidate sedimentological processes (Sanderson and Murphy, 2010;Bishop et al, 2011;Muñoz-Salinas et al, 2011).…”

Luminiscencia Ópticamente Estimulada aplicada a sedimentos fluviales: Un enfoque basado en la interpretación de las señales luminosas

“…La metodología que se aplicó para la recolección de las muestras en campo siguió los protocolos propuestos por Muñoz-Salinas et al (2011). El protocolo conlleva la cobertura del perfil en trabajo de campo con una tela oscura para proceder a la limpieza del material superficial en el afloramiento y así remover todos aquellos granos expuestos a la luz solar.…”

“…La interpretación de las señales de luminiscencia en sedimentos, sin proceder a su datación, ha sido propuesta más recientemente (Sanderson y Murphy, 2010;Muñoz-Salinas et al, 2011;Munyikwa et al, 2012) y se ha puesto de manifiesto que el uso de dichas señales es una herramienta útil en el estudio de sedimentos fluviales para dilucidar los mecanismos de transporte de sedimentos . Ejemplo del uso de este enfoque es el trabajo de Sanderson y Murphy (2010), en el cual se analizan las señales luminosas que provienen de muestras de sedimento extraídas de un perfil vertical que corta los depósitos de un enclave arqueológico en Petrilli, en la región de la Puglia, Italia.…”