%0 Journal Article
%A Tejero López, Rosa
%A González Casado, José Manuel
%A Gómez Ortiz, David
%A Sánchez Serrano, Fernando
%T Insights into the "tectonic topography" of the present-daylandscape of the central Iberian Peninsula (Spain)
%D 2006
%@ 0169-555X
%U https://hdl.handle.net/20.500.14352/50203
%X The landscape of today’s central Iberian Peninsula has been shaped by ongoing tectonic activity since the Tertiary. Thislandscape comprises a mountain ridge trending E–W to NW–SE, the Central System, separating two regions of smoothtopography: the basins of the rivers Duero and Tajo. In this study, we explore interrelationships between topography and tectonicsin the central Iberian Peninsula. Regional landscape features were analysed using a digital elevation model (DEM). Slope gradientsand slope orientations derived from the DEM were combined to describe topographic surface roughness. Topography trendsurfacesinferred from harmonic analysis were used to define regional topographic features. Low roughness emphasizes the smoothnature of the basins’ topography, where surfaces of homogeneous slope gradient and orientation dominate. High roughness wasassociated with abrupt changes in gradient and slope orientation such as those affecting crests, valley bottoms and scarp edgespresent in the mountain chain and in some deep incised valleys in the basins. One of the applications of roughness mapping was itscapacity to isolate incised valley segments. The area distribution of incised rivers shows their prevalence in the east. On a regionalscale, the topographic surface can be described as a train of NE–SW undulations or waves of 20 km wavelength. These undulationsundergo changes in direction and interruptions limited by N–S-trending breaks. E–W and NE–SW troughs and ridges clearly markstructural uplifts and depressions within the Central System. These structures are transverse to the compressive NW–SE stress fieldthat controlled the deformation of the central Iberian Peninsula from the Neogene to the present. They represent the upper crustalfolding that accommodates Alpine shortening. N–S breaks coincide with Late Miocene faults that control the basins’ sedimentation.Further, associated palaeoseismic structures suggest the recent tectonic activity of N–S faults in the eastern part of the TajoBasin. Apatite fission track analysis data for this area suggest the occurrence of a significant uplift episode from 7 to 10 Ma whichinduced the river incisions appearing in the roughness map. N–S and NE–SW faults could be seismogenic sources for the currentmoderate to low seismic activity of the east Tajo Basin and southeast Central System. Although N–S fault activity has already beenestablished, we propose its significant contribution to shaping the landscape.
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