Thermochronometry constraints on south West Greenland passive continental margin development

Rifting and passive margin formation between Greenland and North America took place from the late Triassic through to the Early Cretaceous, according to low-temperature (U-Th)/He thermochronology and landform analyses from southern West Greenland. Passive continental margins (PCMs) represent the interface between the marine and terrestrial realms. However, topographic evolution of PCMs is often difficult to decipher due to paucity of the preserved geological record. Here, we report uranium-thorium-helium ((U-Th)/He) analysis of the Precambrian crystalline basement from southern West Greenland that help constrain the process of rifting between Greenland and North America and contributes to the debate about the West Greenland PCM development. The majority of zircon (U-Th)/He dates (220-580 Ma) imply several kilometres of burial of the basement by Paleozoic (and potentially Mesozoic) sediments. Apatite (U-Th)/He dates (80-230 Ma) record thermal processes associated with extensional tectonism starting in the Late Triassic and passive margin formation in the Early Cretaceous. Our data provide no evidence of thermal activity during Cenozoic times, suggesting that the thermal effects of Paleogene rifting and break-up were negligible and the magnitude of Cenozoic erosion was <3.5 km in the study area.