Thermal evolution of onshore West Iberia: A better understanding of the ages of breakup and rift-to-drift in the Iberia-Newfoundland Rift

The age of breakup which formed the Central-North Atlantic has been debated for many decades and is still subject to debate: from ca. 150 Ma 110 Ma. To address this issue, we have carried out a thermochronological study eastern margin rifted Iberia-Newfoundland sector. New apatite fission-track (AFT) data acquired on samples footwall (Variscan basement) one sample (Triassic Lusitanian Basin) hanging wall principal normal fault bounding basin. Thermal history western Iberia can be then reconstructed since 250 Fission-track ages Variscan granitoids (whose crystallization >275 Ma) range between 191 ± 8 75 5 Ma, indicating that significant thermal events affected area during period. inversion supports two main cooling attribute major uplift denudation basement, consistent with widespread basement-derived siliciclastic rocks similar ages: Late Jurassic/Early Cretaceous (ca. 150–145 late Early Ma). From sedimentary record in Basin new AFT data, deduce that: (1) temperatures >70–110 °C west 190 explained partly by subsiding basement both foot walls; (2) event at interpreted as rift flank uplift; (3) may linked final evolution onset oceanic spreading. We infer reflects break elastic core lithosphere (whole failure = breakup) shoulder (end Rift 1), was followed hyper-extension mantle exhumation (Rift 2) finally, spreading (rift-to-drift) (onset 3).