Tectonic and sediment provenance evolution of the South Eastern Pyrenean foreland basins during rift margin inversion and orogenic uplift

摘要

The Cretaceous to Oligocene detrital record in the southern Eastern Pyrenees is utilized to address the degree to which precursor basin architecture and hyper-extensional rift structures impacted subsequent sedimentary provenance and dispersal systems and foreland basin evolution. This study presents new isotopic provenance analysis of detrital zircon U-Pb and (U-Th)/He double-dating, and detrital rutile U-Pb and trace element geochemistry to track sediment provenance evolution. Late Cretaceous-Paleocene sediments show zircon with dominantly Variscan U-Pb and Jurassic-Early Cretaceous ZHe cooling ages that are derived from southeastern Catalan Coastal Ranges and eastern Corsica-Sardinia regions, and localized structural inversion along inherited Mesozoic extensional faults and erosional recycling of syn-rift sediments. Eocene deposits have multimodal U-Pb ages that stratigraphically upsection change to unimodal Variscan ages, with the appearance and upsection increase in Pyrenean ZHe ages, and increase in Variscan aged detrital rutile that record a significant shift in sediment source area to northern sources recording exhumation and unroofing of the Axial Zone Paleozoic basement sources, and development of new ramp-flat style structures in the Southern Pyrenean Zone fold-thrust belt. During the Oligocene, incipient foreland basin deposits were cannibalized and recycled into the foreland basin as thrusting advanced toward the foreland. The Eastern Pyrenean foreland basin records a different provenance history from Central Pyrenean Tremp Basin, suggesting the basins were segmented throughout the Late Cretaceous to Oligocene, while the Ripoll and Ager basins appear to have shared similar source areas. The sediment provenance evolution coupled with Pyrenean fault activity and shortening rates, hinterland exhumation, foreland basin subsidence, and climate proxies presents a detailed dataset to understand these relationships within the Eastern Pyrenean orogenic system an