Thermo-tectonic record of hyperextension, structural inversion, and foreland basin evolution of the eastern and central Pyrenees

Odlum, Margaret Larkin
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Direct constraints on processes associated with rifting and mantle exhumation are necessary to understand the thermal and structural evolution of continental rift systems, and the role of pre-existing crustal architecture on orogenesis and foreland basin development. This work constrains the Early Cretaceous hyperextension history along the Iberia-European margin and how rift inheritance affected the structural and foreland basin evolution of the Late Cretaceous-Oligocene Pyrenean orogeny. Chapters 1 and 2 aim to understand the thermal and structural evolution of the North Pyrenean basement massifs during Early Cretaceous rifting and hyperextension using multi-mineral thermochronometry. These chapters integrate zircon, apatite, and rutile U‐Pb ages from the Agly and Saint Barthélémy massifs that provide new constraints to understand the decoupled versus coupled extensional evolution, exhumation timing of the middle‐lower crust, and the age of juxtaposition of the upper crust granitic pluton with middle crustal gneisses, and fluid-rock interactions along a detachment fault. Novel method integration and approaches using apatite were developed and implemented in these chapters to best interpret the apatite U-Pb ages to gain the most insight into thermal, structural, and fault zone processes in the Early Cretaceous rift system’s distal margin. Chapters 3 and 4 use the sedimentary record in the pro-wedge foreland basins of inversion and orogenesis to understand the provenance, hinterland evolution, and the role of extensional inheritance on the orogenic phase of the margin. This work shows that the eastern Pyrenean foreland basin deposits were sourced from Corsica-Sardinia and the Catalan Coastal Ranges during the Late Cretaceous-Paleocene, and the Pyrenees beginning in the Eocene. Detrital mineral trends across the basins suggest that the pro-wedge foreland basin developed and remained segmented throughout the Late Cretaceous-Oligocene. The results from these chapters highlight the dominant control of inherited structures and rift basins on controlling the sediment provenance and foreland basin architecture in inverted rift systems. The dissertation aims to show the structural evolution of the Early Cretaceous rifting and thermal and structural processes that were operating within the continental crust at the rift margin, and how this inherited rift architecture affected the orogenic evolution and foreland basin development during the Pyrenean orogeny. These results add to our overall understanding of the structural and thermal evolution during rifting and continental break-up and role of rift inheritance in the evolution of superimposed orogenic systems and their associated foreland basins