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Hyper-extended, magma-poor rifted margins are characterized by thinned continental crust, exhumed subcontinental mantle, and limited volcanism. The timing of exhumation, particularly mantle exhumation, during the formation of hyper-extended margins has key implications for our geodynamic understanding of the transition from continental breakup to seafloor spreading and the relationship between magmatism, lithospheric extension, and mid-ocean ridge development. We use zircon and apatite from rifted igneous intrusions and lower continental crustal blocks within the exhumed mantle section of the Iberia-Newfoundland margin to track the cooling of these rocks below ~200°C, with implications for fault timing and fluid-rock interactions. Zircon (U-Th)/He data from 8 core samples (from 4 drill holes) exhibit a general younging trend from east to west during the Late Cretaceous, consistent with exhumation driven by a lithosphere-scale, westward-dipping detachment fault. Of 10 apatite (U-Th)/He samples (from 7 drill holes), 5 record Cretaceous cooling, while the remaining 5 indicate Oligo-Miocene cooling, with no clear geographic pattern distinguishing the two populations. Inverse thermal history modeling will be applied to constrain the thermal evolution of the lithosphere during hyperextension. These models can indirectly constrain the timing at which the lithosphere entered the thermal window conducive to serpentinization and ophicalcite formation with implications for lithospheric rheology, thermal structure, and the potential habitability of subsurface environments for ancient microbial life.