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Quaternary landscape evolution: a framework for understanding contemporary erosion, southeast Spain
Author(s) -
Mather A. E.,
Stokes M.,
Griffiths J. S.
Publication year - 2002
Publication title -
land degradation and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 81
eISSN - 1099-145X
pISSN - 1085-3278
DOI - 10.1002/ldr.484
Subject(s) - geology , lithology , landslide , erosion , karst , terrain , geomorphology , physical geography , hydrology (agriculture) , paleontology , geography , cartography , geotechnical engineering
Recent research into the long‐term landscape development of a tectonically active terrain in arid SE Spain has revealed the significance of river capture in understanding current landscape instabilities (badlands and landslides). The river capture was initiated at c .100 ka BP and effected a 90 m base‐level change at the point of capture. This stimulated a wave of incision to propagate through the landscape to 20 km upstream of the capture site. The net effect of the associated increase in erosion has been to change valley shapes from broad and shallow to narrow and deep. The associated unloading and steepening of valley sides has led to a focus of landslide activity in lithologies with more unconfined compressive strength (limestones) and a dominance of gullying, piping and badland development in the lithologies with lower unconfined compressive strengths (marls and sands). Post‐capture rapid valley widening was initially achieved through landslide development. This form of slope degradation was sustained in the more resistant, joint‐controlled lithologies. In weaker lithologies it was superseded by badland development. The elevated sediment fluxes associated with the c .100 ka BP base‐level perturbation will continue into the near future, but are expected to decay, assuming that no additional environmental disturbances occur. The patterns of landscape instability witnessed today are controlled by (1) proximity to the areas affected by the base‐level change and (2) the robustness of the local geology. Understanding of this long‐term temporal context of the landscape provides a valuable spatial and temporal framework for land system management, facilitating the prediction of future natural trends in landscape stability. Copyright © 2002 John Wiley & Sons, Ltd.