Landscape forcing mechanisms on Quaternary timescales: The Tabernas Basin, SE Spain

Abstract

Quaternary landform features and their associated sedimentary assemblages (river terraces and alluvial fans) often provide important records of long-term landscape evolution. The reconstruction of global terrace sequences has enabled the identification of numerous external and internal forcing mechanisms which operate within the Quaternary landscape system. The relative effects of these forcing mechanisms are highly variable over a range of spatial and temporal scales. In this research, a combined study approach is adopted in order to ascertain the significance of external (e.g. tectonics, climate) and/or internal (e.g. lithological thresholds) forcing mechanisms upon patterns of Quaternary landscape development within the Tabernas Basin, SE Spain.The results of extensive field investigation have developed a four-tiered landform stratigraphy (i.e. basin wide terrace levels) for the Tabernas Basin. Chronological constraints for the Quaternary stratigraphy were obtained from Optically Stimulated Luminescence dating. Age estimations develop a pattern of climatically driven terrace aggradations during glacial phases throughout the Middle to Late Pleistocene. This pattern fits well with regional models of enhanced terrace formation during glacial phases after the Middle Pleistocene.The Quaternary stratigraphy of the Tabernas Basin was investigated by methods of geospatial interpolation and numerical modelling. The results of conceptual and quantitative modelling approaches highlight the dominance of non-uniform rates of base-level change driven by variable rates of tectonic uplift throughout the Mid-Late Pleistocene. Enhanced uplift in the west of the basin associates well with regional patterns, with tectonically driven base-level changes focused in the eastern Alpujarran Corridor. Internal landscape thresholds were important in the Holocene development of the Tabernas basin. Increased rates of incision in the final stages of basin development were likely attributed to the effects of lithological controls coupled with anthropogenic activity in the basin catchment.