%0 Journal Article
%T Long-term denudation rates from the Central Andes (Chile) estimated from a Digital Elevation Model using the Black Top Hat function and Inverse Distance Weighting: implications for the Neogene climate of the Atacama Desert Tasas de denudaci車n de largo tiempo en los Andes Centrales, Chile, estimadas a partir de un modelo digital de elevaci車n usando la funci車n 'Top Hat' por cierre y la interpolaci車n ponderada por el inverso de la distancia: implicancias del clima Ne車geno del Desierto de Atacama
%A Rodrigo Riquelme
%A Jos谷 Darrozes
%A Eric Maire
%A G谷rard H谷rail
%J Revista geol車gica de Chile
%D 2008
%I Scientific Electronic Library Online
%X A methodology for determining long-term denudation rates from morphologic markers in a Digital Elevation Model (DEM) is checked by a comparative study of two drainage basins in the PrecordiUera of the Central Andes. In both cases the initial configuration of an incised pediment surface has been restored by using two different methods: the Black Top Hat (BTH) function and the Inverse Distance Weighting (IDW) interpolation. Where vertical incision and hillslope erosion are recorded, the IDW appears to be the most adequate to reconstitute the pediment surfaces. Conversely, where only vertical incision is observed, the BTH describes more precisely the former pediment surfaces and it is easier to solve. By subtracting the DEM from the reconstructed marker we calculated an eroded volume, and estimated its uncertainty by considering Root Mean Square Error (RMSE) and DEM grid error. For the last ~10 Myr we obtained long-term denudation rates of 7.33㊣1.6 m/Myr in the San Andr谷s drainage basin and 13.59㊣1.9 m/Myr in the El Salado drainage basin. These estimations are largely in agreement with other reported estimates of long-term denudation rates in the Atacama Desert. Comparison with long-term denudation rates reported in a wide range of climatic regimes suggests that our estimates cannot be explained by the current rainfall in the PrecordiUera. However they could be explained by a rainfall similar to that reported 40 km to the east in the Puna. This suggests that during the time span concerned the geomorphologic evolution of the study area, this evolution is dominated by an orographically controlled rainfall pattern. The preserved pediment surface and the small long term denudation rates determined in this study also indicate that the PrecordiUera was never reached by humid tropical air masses and precipitation as currently observed in the Altiplano during the summer months Una metodolog赤a para determinar tasas de denudaci車n de largo tiempo a partir de marcadores geomorfol車gicos obtenidos desde un Modelo Digital de Elevaci車n (MDE), ha sido comprobada considerando un estudio comparativo de dos cuencas vertientes de la precordillera de los Andes Centrales. Para ambas cuencas, la configuraci車n inicial de una superficie de pedimentaci車n afectada por incisi車n, ha sido reconstruida usando dos m谷todos diferentes: la funci車n 'Top Hat' por Cierre (THC) y la Interpolaci車n Ponderada por el Inverso de la Distancia (IPID). Cuando se observa tanto incisi車n vertical como erosi車n de laderas, la IPID es m芍s apropiada para reconstruir las superficies de pedimentaci車n. Por el cont
%K Geomorfolog赤a cuantitativa
%K MDE
%K Andes
%K Denudaci車n de largo tiempo
%K 'Top Hat'por Cierre
%K Quantitative geomorphology DEM
%K Andes
%K Long-term denudation
%K Black Top Hat
%U http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-02082008000100005