Quaternary stream incision and topographic development in the eastern Alpujarran Corridor, Betic Cordillera, southern Spain (Almeria)

Base-level lowering caused by tectonic uplift propagates through fluvial systems for tens of kilometers as a wave of vertical stream incision. Little is known about time dependent climatic and geologic factors controlling the shape and rate of incision wave migration. I use historical geology to assess the effects of climatic fluctuations and changes in sediment supply on how an incision wave is manifest in a fluvial network that drains a 1270 km 2 catchment.; I mapped surficial geology along a 42 km reach of the eastern Alpujarran Corridor's (“EAC”) trunk stream (Rio Andarax). Numeric age control for EAC Quaternary geochronology was established through Th/U series dating of travertine strata, which are interbeds within fluvial sequences. Travertine ages were extrapolated to fluvial landforms elsewhere in the EAC via chronostratigraphic correlation based on landscape position as well as calcrete crust macro and micromorphology. The numeric age of a younger alluvial-fan sequence is estimated on the basis of regional morphostratigraphic correlation and soil properties.; Understanding deformational style is essential to evaluate factors governing incision wave processes. I show that Mid and Late Pleistocene deformation in the EAC is dominated by regional uplift, and that the oxygen isotope Stage 8 (“ois8”; 303–245 ka) to present regional rock uplift rate is between 0.3 and 0.7 m/ka.; The Rio Andarax incision wave was triggered by regional uplift, and between ois8 and oxygen isotope Stage 2 (“ois2”; 21–12 ka) it moved 7.7 km upstream at a rate between 27 and 34 m/ka. Increased sediment loads caused by the ois8 climatic event temporarily stopped the incision wave from moving through Rio Andarax tributaries. By ois2, stream catchments were depleted of sediment, and consequently this climatic event did not stop the incision wave from moving through the Andarax network. These results indicate that the rate at which an incision wave moves upstream is controlled by a complex interaction of climatic fluctuation and available sediment in drainage catchments.