Break up and Post-Breakup Magmatism between the conjugate margins of the Vøring Plateau and East Greenland, NE Atlantic

The Northeast Atlantic Igneous Province (NAIP) formed during the Paleocene/Early Eocene, driven by the Iceland hotspot. Its volcanic margins show a positive correlation between igneous thickness (H) and lower-crustal P-wave velocity (V_P), indicating that high-temperature is driving excess mantle melting. However, previous studies have argued for large variations in structure and magmatic volumes between the conjugate margins of the Vøring Plateau and East Greenland, and there are inconsistencies in defining the conjugate continent-ocean transition zones (COTs). In this study, we use the H-V_P correlation from various wide angle seismic studies, where a positive trend identifies igneous crust, while a rapid transition to a strong negative trend marks the increased presence of continental crust to redefine the COTs on conjugate Vøring Plateau and East Greenland margins. This definition gives consistent COTs in plate reconstruction to opening. Our results show that the total  magmatic volume of the East Greenland margin (8.23 × 10⁵ km³) is only slightly larger than for the Vøring Plateau (7.51 × 10⁵ km³). Later secondary magmatism in East Greenland (Late Eocene to Miocene) occurred during the separation between East Greenland and the Jan Mayen Microcontinent. Assuming symmetric magmatic volumes on each plate after breakup between the East Greenland margin and the Vøring Plateau, the difference can be used to estimate secondary magmatic volume in East Greenland (0.72 × 10⁵ km³), which is less than 10% of the initial breakup magmatism. In addition, other post-breakup mid-to-late Cenozoic events including Logi Ridge, Jan Mayen Plateau, Vesteris Seamount, Jan Mayen Island and Vøring Spur, contribute an estimated total volume of 2.2 × 10⁵ km³. While quite visible, the igneous volume of these events is thus far less than the Early Eocene breakup magmatism.