Some specific aspects of postvolcanic relief evolution in the Harghita Mountains

Abstract

The Harghita Mountains represent the final and thus youngest segment of the Inner Carpathian
Volcanic Chain. They are characterized by two contrasting geomorphologic levels. The first, upper level
is that of the volcanic cones; the second represents the volcanic plateau of the ring plains, and this has
been preserved mostly on the western side. Most of the cones are effusive and are mainly made up of
coherent volcanic rocks (predominantly andesite), while the surrounding plateau was formed by the
accumulation of volcaniclastic material. Due to their various petrological and chemical characteristics,
the two types of rocks has responded differently to the erosion processes, resulting in diverse
morphologies of the cones and the plateau.
The evolution stages of the volcanic relief have been studied, especially the two edifices of the
Southern Harghita, - i.e. the Pili§ca and Ciomadu cones. In the light of new petrological and
geochronological data, and on the basis of our own geomorphological research, we have clarified some
aspects focusing primarily on the evolution of the fluvial relief.