Revistes Catalanes amb Accés Obert (RACO)

Coupling far and near tectonic signals in syn-orogenic sediments: the Olvena growth strata (Sierras Marginales, southern Pyrenees).

P. Santolaria, Mª Aránzazu Luzón Aguado, A.M. Casas, R. Soto

Resum


The Olvena area (Sierras Marginales, Southern Pyrenees) provides an outstanding example for studying the relationships between tectonics and sedimentation related to fold-and-thrust systems having shallow décollements. Stratigraphic and sedimentological analysis allows to infer the interference of Oligocene locally-sourced alluvial fans and a far-sourced wider fluvial system. Initially, uplift resulting from folding and thrusting precluded the entrance of the north-coming wider fluvial system and isolated a subsiding area filled by west-flowing alluvial fans sourced in the rejuvenated reliefs. Subsequently, these reliefs were subdued yielding sedimentation associated with the north-coming fluvial system. Sequential evolution and stratigraphic architecture evidence thrust emplacement chronology, including out-of-sequence structures and the influence of evaporite flow along thedécollement. Despite these syn-tectonic deposits are linked to the Ebro Basin deposition, its megasequential evolution differs from the general sequence, highlighting the importance of differentiating the influence of near-coming sedimentary systems when interpreting basin-scale sequence stratigraphy.

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