Resumo

MORA P., Lucy; BONIFAZ, Roberto  e  LOPEZ-MARTINEZ, Rafael. Unidades geomorfológicas de la cuenca del Río Grande de Comitán, Lagos de Montebello, Chiapas-México. Bol. Soc. Geol. Mex [online]. 2016, vol.68, n.3, pp.377-394. ISSN 1405-3322.

Geomorphological characterization is a tool which can be used for a better understanding of landscape evolution and also to understand the natural dynamics of a system and has broad applications for earth sciences.

The Río Grande de Comitán-Lagos de Montebello watershed is located in the southeastern part of the Mexican state of Chiapas, between the Chiapas central plateau and the Gulf plain, and shares a border with Guatemala. It is a karstic watershed formed by marine and transitional sedimentary sequences, the distribution of which are controlled by tectonic highs, in which second order geomorphological units were defined in order to understand the evolution, function and dynamics of the watershed.

Using a geographic information system and a digital elevation model, the geomorphological units were defined based on morphometric criteria such as height, slope and relief. Later, those units were validated analyzing differences in roughness, slope and elevation for each geomorphological unit.

Using this procedure we defined the main geomorphic areas (mountains, hills and plains). These broad classifications were subdivided into thirteen geomorphological units. The final delineation was supported by expert criteria and field work. Different periods of evolution and different stages of karst development were identified. Processes controlling the geo-forms are principally dissolution-erosion and reactivation of old karst areas due to regional tectonic dynamics. In this sense, the current evolution of the area can be understood as multifaceted with several stages. This first step of the watershed characterization allows defining units related to erosion by surface flow and areas with more karst development, and therefore increased dynamics of the subsurface water.

Palavras-chave : karst geomorphology; morphometry; Lagos de Montebello; Chiapas; Mexico..