Morphologisch-morphometrische analyse eines vulkanischen aschenkegelfeldes hober räumlicher dichte - Payun Matru, südliche zentralanden, Argentina

A large number of monogenetic cones were analysed to establish their relative ages in the southern Andes mountains. The Andino-Cuyano Basaltic Province, of Pliocene to Holocene volcanism age in Mendoza, Argentina, with about 800 cinder cones provides an excellent field study for the geomorphological development of the volcanic field. The morphometric ratio H_co/W_co-height/basal diameter-declines rapidly after eruption, from a value of 0.26 for the sub-recent Santa Maria cone probably less than a thousand years old to 0.18 for the Los Volcanes cones of several thousands of years and finally to 0.10 for the Pliocene volcanoes. The rapid decline on a logarithmic time scale is similar to the Michoacan cones in Mexico and to the erosion trend shown for the Paricutin cone. The slope angles decline as well with time, from the initial 30°-34° for the fresh cones to 18° for the old cones. These trends are probably due to the semiarid conditions prevailing in the area during the Pleistocene period, with high rates of erosion processes. The morphometric and morphological characteristics allowed for a detailed relative time classification of the volcanic field.