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Temporal Constraints on Multiple Rifting Stages of a Hyper-Extended Continental Margin using Coupled Bedrock and Detrital Double-dating, Mauleon Basin, Western Pyrenees

Nicole Hart
The University of Texas at Austin, Jackson School of Geosciences, Austin, Texas, United States of America
[email protected]

Multi-mineral double-dating of detrital and bedrock units from a hyper-extended continental margin have the potential to show the detailed evolution and timing of continental rifting. Through zircon (U-Th)/He and detrital zircon U-Pb dating techniques, sediment provenance and the temporal and thermal evolution of the tectonically active source areas can be constrained. Additionally, hyper-extended margin basins, such as the Mauléon basin, contain syn-rift basins which hold inverted unroofing sequences with up-section variation in lag time that record changes in sediment source and exhumation rates during progressive continental break-up. These sediments deposited in syn-rift basins typically archive a more complete history of margin evolution than bedrock alone that is prone to thermal overprinting or erosion. Furthermore, zircon and rutile U-Pb-He and detrital U-Pb-He double-dating studies have shown the power of coupling these data with other geochemical characteristics to refine provenance and reconstruct the tectonic evolution of hyper-extended continental margins. The Mauléon Basin is an ideal field location due to extreme crustal thinning during the Cretaceous followed by Pyrenean reactivation. Since reactivation and deformation is minimized to the west; pre-, syn- and post-rifting units and structures in the basin are accessible. This study is the first major chronologic study of bedrock and detrital units completed in the Mauléon Basin. It will contribute new insights into continental rifting, the thermal and structural evolution of the Mauléon Basin and the Western Pyrenees, plate reconstructions and kinematics of the Iberian and European plates and a greater understanding of these systems and their relationship to hydrocarbons.

AAPG Search and Discovery Article #90183©2013 AAPG Foundation 2013 Grants-in-Aid Projects