Study of sediment erosion at the headwaters of the Amalacaxco and Altzomoni gulches (Iztacc?huatl-Popocat?petl Zoquiapan National Park, Mexico) by means of optically stimulated luminescence

The study of sediment transport is important to understand how erosive processes operate on the earth's surface and to try to manage natural resources in an optimal way. This paper studies the mechanisms of surface transport of sediments in two high mountain headwaters that have similar topographic and lithological characteristics with an ecosystem of high ecological value characterized by the alpine grassland. These headwaters are distin-guished in that one is in a natural state, located in the Altzomoni gorge, and the other has implemented management practices consisting of the construction of infiltration trenches and afforestation, in the Amalacaxco gorge. Both headwaters are located within the Iztaccihuatl-Popocatepetl Zoquiapan National Park (central Mexico). In the study, the luminescence signals were analyzed with the opti-cally stimulated luminescence (LOE) technique to understand the degree of erosion that exists. The luminescence of the two deposits that make up the surface of the two headwaters was estimated and the LOE signals were analyzed in samples taken on the surface in longitudinal profiles along the slope in three different periods of one year, this to consider the variability associated with seasonal changes. The results indicate that most of the materials that are mobilized downhill come from the surface deposit. However, during the months that concentrate the greatest rainfall and solar radiation, the subsurface materials, more than 80 cm deep, but only in the Amalacaxco gorge, are mobilized punctually. This indicates that erosion is greater in the gorge where the management techniques were implemented, which contrasts with what is observed in the gorge in its natural state. It is concluded that the management techniques applied modify the surface dynamics and favor the incisive processes of the alpine grassland. The use of the method used is appropriate to study erosive processes in high mountain areas.