Evolution of the source mineralogy and lithospheric controls on magmatism during the Northeast Atlantic continental breakup

The mid-Norwegian Margin, part of the North Atlantic Igneous Province (NAIP), is a well-studied volcanic rifted margin formed during the breakup between Greenland and Eurasia ~56 Mya. However, the main controls on magmatic productivity during continental breakup remain debated. To better understand the drivers of breakup magmatism, we developed an inverse Monte Carlo statistical melting model that infers source mineralogy from basalt chemistry. When applied to basalts recently recovered on the Vøring Margin, our results reveal a clear shift in source mineralogy during rifting, with peak magmatism coinciding with clinopyroxene enrichment, despite mantle potential temperatures being capped below 1500°C. We show that while the proto-Iceland mantle plume likely played a role during the emplacement of the NAIP, the main driver for the continental breakup magmatism is lithospheric thinning. This study provides new insights into the magmatic and geodynamic evolution of the mid-Norwegian Margin, emphasizing the role of lithospheric refertilization in driving breakup magmatism.