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

形成中北大西洋的分裂时代已经争论了数十年，至今仍在争论：150 Ma至110 Ma。为了解决这个问题，我们对裂陷的伊比利亚-纽芬兰地区的东部边缘进行了热年代学研究。新的磷灰石裂变径迹（AFT）数据是从下盘（Variscan地下室）的样本中获取的，而从该盆地的主要正断层的悬挂壁的样本（Lusitanian盆地的三叠纪）中获取的。西元伊比利亚的热史可以重新建立，因为约。250毫安。Variscan花岗岩的裂变径迹年龄（其结晶年龄> 275 Ma）介于191±8 Ma和75±5 Ma之间，表明在此期间重大的热事件影响了研究区域。热反演支持两个主要的降温事件，我们将其归因于瓦里斯卡纳基底的一次隆升和剥蚀，这与年龄相似的广泛的基底衍生的硅质碎屑岩一致：晚侏罗世/早白垩世（大约150-145 Ma）和早白垩世晚期（大约110 Ma）。根据卢西塔尼亚盆地的沉积记录和新的AFT数据，我们得出以下结论：（1）大约70-110°C的温度影响了西伊比利亚岛之间的西伯利亚。190和150 Ma，这在一定程度上可以归因于脚壁和悬壁的地下室塌陷。（2）大约主冷却事件。150–145 Ma被解释为大裂谷后缘隆升；（3）ca。110 Ma的降温事件可能与边缘的最终演变和海洋扩张的开始有关。我们推断，AFT主冷却事件大约在 150–145 Ma反映了岩石圈弹性核心的破裂（整个岩石圈破坏=破裂），并伴有明显的裂谷肩部抬升（裂谷1的末端），然后是超伸和披肩发掘（裂谷2），最后，大约在1989年通过海洋传播（从漂移到漂移）。110 Ma（第3裂谷的开始）。