Assessing paraglacial processes at Nexpayantla Gorge (Popocatépetl volcano, Central Mexico) using OSL and¹⁴C

Abstract

We evaluate the paraglacial activity in Nexpayantla, a subtropical mountainous gorge in Popocatépetl volcano (Central Mexico), fully deglaciated in the 20th century. Glacial advances are evidenced by the presence of moraines. Fluvio‐glacial terraces and an alluvial megafan resulted from the gorge deglaciation. Current reworking of the glacigenic material is done by landslides and debris flows produced on the moraines and terraces. To study the different phases of mobilization of glacigenic sediment, we used an approach based on the study of the optically stimulated luminescence (OSL) signals obtained from a portable OSL (POSL) reader in samples extracted from both glacigenic and paraglacial deposits. The luminescence (POSL) results obtained at moraines increase as altitude decreases, which is expected for deglaciated valleys where the oldest moraines are located at lower elevations. We evaluate the grade of luminescence signal reset of the glacigenic sediments during the proglacial stage, and the subsequent deglaciation phases. Our results indicate that there is a marked transition between glacial and fluvially dominated processes at Nexpayantla Gorge. We find that the grade of luminescence signal resetting in the paraglacial deposits is a good indicator to trace paraglacial stages and the beginning of exhaustion of the paraglacial activity in mountain areas. OSL ages confirm that the oldest fluvio‐glacial terraces found at the middle sector of Nexpayantla Gorge are ~2 ka, which is also supported by an AMS 14C age. OSL dating was found challenging, since quartz grains have low sensitivity because of their volcanic origin; POSL signals, however, are in good agreement with the location and distribution of geomorphic markers. We propose that luminescence data obtained from the POSL unit can be useful to provide information about sediment mobilization in paraglacial environments during different climatic pulses – even for the case where mineral grains have low sensitivity, such as in volcanic sediments. © 2020 John Wiley & Sons, Ltd.

Optically Stimulated Luminescence Phosphors: Principles, Applications, and Prospects

“…The increased utilization of OSL‐based luminescence dating presents its capacity to date events beyond other methods and enables chronological frameworks to be established. [ 24,292–329 ]…”

Aplicación de VolcFlow para simular Avalanchas de Escombros y CDP en los volcanes Popocatépetl, Volcán de Colima y Ceboruco

“…La geología evolutiva del Popocatépetl ha sido sintetizada por diversos autores en las que destaca el artículo de Macías (2006) entre otros (Robin, 1984, Carrasco-Nuñez, 1985Mendoza-Rosas y De la Cruz-Reyna, 2008, 2009Siebe et al, 2017;Macías et al, 2020;). Diversos autores consideran tres etapas principales: en la primera etapa el edificio del volcán primitivo, también conocido como volcán Nexpayantla (Muñoz-Salinas et al, 2020), donde se identifica el colapso parcial por la región lateral que produjo la formación de una caldera hace 200,000 años A.P. Similar a los observados en Mount Saint Helens en 1980 y a la del Volcán de Colima hace 4500 años, de acuerdo con Luhr y Prestegaard (1988) y Hoblitt et al (1981.…”