Assessing paraglacial processes at Nexpayantla Gorge (Popocatépetl volcano, Central Mexico) using OSL and 14C. Issue 11 (5th June 2020)

• Record Type: Journal Article
• Authors: Muñoz‐Salinas, E.; Castillo, M.; Franco‐Ramos, O.; Arce, J.L.; Sanderson, D.C.W.; Cresswell, A.C.
• Is Part Of: Earth surface processes and landforms. Volume 45:Issue 11(2020)
• Page Start: 2450
• Page End: 2462
• Publication Date: 2020-06-05
• Subjects: paraglacial processes -- glacigenic sediments -- OSL -- Nexpayantla Gorge -- Central Mexico; Geomorphology -- Periodicals; 551.4
• DOI: 10.1002/esp.4890
• Languages: English
• ISSNs: 0197-9337

Abstract

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 14 C 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. Abstract : We evaluate the grade of luminescence signal reset of glacigenic deposits formed from volcanic materials at Nexpayantla Gorge (Central Mexico) using a portable OSL (POSL) reader. Results indicate a marked transition between glacial and fluvially dominated processes as proglacial deposits are better reset than those occurring after deglaciation. Our main conclusion is that POSL signals can be useful to provide information on sediment mobilization during different climatic pulses, even when mineral grains have low sensitivity as in volcanic sediments.