Active fault control in the distribution of Elevated Low Relief Topography in the Central-Western Pyrenees
Ortuño Candela, Maria (Universitat de Barcelona. Departament de Dinàmica de la Terra i de l'Oceà)
Viaplanas-Muzas, Marc (Consejo Superior de Investigaciones Científicas. Instituto Jaime Almera (Barcelona))

Data:	2018
Resum:	The activity of normal faults in the Central-Western Pyrenees is mainly detected by the disruption of paleic landforms surviving to Plio-Quaternary incision: the remnants of a Low-Relief Topography (LRT) that probably originated asynchronically during the Oligocene and Miocene. We propose a new method for mapping the LRT remnants that combines automatic analysis of digital topography and cross-checking with regional databases of Quaternary landforms. We focus on an area where the location of the main-drainage divide seems to be influenced by the activity of the Bedous-Pic de Midi du Bigorre set of faults and by the North Maladeta Fault. Neotectonic markers defined by the remnants of LRT envelops are tectonically displaced up to ~700m by the previously identified faults, but also along new faults observed in between them. A western prolongation of the North Maladeta Fault has been identified for the first time, implying a 75km total trace length, almost twice thepreviously published value. A restoration of the fault block motion was performed assuming a regional uplift across the range, enhanced in the northern part of the Axial Zone. This uplift leads to an outer arch extension along the Maladeta-Bedous Fault System. The resulting paleo-topography shows a broad southern paleo-flank (up to ~120km long) with a gentle regional gradient (~1º) and a much shorter and steeper northern paleo-flank (~4º gradient, up to 30km-long). This configuration suggests that the LRT remnants now located North of the main divide were connected to the Ebro Basin. The results are supported by previous studies on age and source provenance of major alluvial systems mantling the northern and southern flanks of the chain.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Drainage divide ; Neotectonics ; Post-orogenic uplift ; DEM analysis ; Low Relief Topography (LRT)
Publicat a:	Geologica acta, Vol. 16 Núm. 4 (December 2018) , p. 499-518 (Articles) , ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/347826
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/GeologicaActa2018.16.4.10
DOI: 10.1344/GeologicaActa2018.16.4.10

20 p, 5.6 MB

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