Weathering and landform development in a subtropical mountainous terrain, Veladero massif, Mexico by Piotr Migon ´, Wrocław and Irasema Alcántara-Ayala, Mexico City with 9 figures and 1 table Summary. Granite topography of the Veladero massif, south Mexico, is a heavily dissected all-slopes type of relief. Rock slopes and tor-like residuals occur near the crests, whereas expo- sures within middle and lower slopes show deeply disintegrated granite, often with corestones. Weathering grade is low to intermediate, with kaolinite, smectite and illite present in the most weathered top parts of the saprolite and in the colluvium. Hillslope geomorphology indicates that shallow debris slides are a common means of mass transfer, leading to the build-up of col- luvial aprons. Valley floors are filled by thick debris flow deposits, further pointing to the role of episodic, large-scale geomorphic events. A long-term balance between the rate of weather- ing front descent and the rate of slope lowering is suggested. Current landforms and geomor- phic legacy in the Veladero massif appear consistent with the steady-state evolutionary model, inferred from rock exhumation studies. 1 Introduction Weathering is being increasingly recognized as a key component of landform evolu- tion, particularly in the long-term perspective and in low latitude terrains (Thomas 1994, 2006). Conceptual models involving deep-reaching alteration of rock and sub- sequent sediment transfer have been successfully established for plains and hilly relief (e. g. Büdel 1957, Thomas 1989), and the growing interest in absolute dating of sapro- lites (Vasconcelos 1999, Carmo & Vasconcelos 2006) is paving the way towards establishing quantitative relationships. Studies in mountainous settings are less fre- quent, and the complete understanding of linkages between weathering and other processes is yet to achieve. It is becoming clear, however, that deep weathering is not limited to plains but occurs widely in tropical and subtropical mountains, leading to the development of a saprolitic cover of variable thickness and mineralogical charac- teristics (Thomas 1995, White 2002). The relationships between deep weathering and slope evolution are two-direc- tional. On one hand, the extent and nature of mass movement is influenced by the characteristics of the underlying weathering mantle, hence the latter are of significant interest to engineering geology (e. g. Au 1998, Chigira 2001). On the other one, short- and long-term slope behaviour and dynamics set boundary conditions for Z. Geomorph. N. F. 52 1 1–16 Berlin · Stuttgart March 2008 DOI: 10.1127/0372-8854/2008/0052-0001 0372-8854/08/0001 $ 4.00 © 2008 Gebrüder Borntraeger, D-14129 Berlin · D-70176 Stuttgart