Mantle heterogeneity drives spreading center dynamics at Arctic Mid-Ocean Ridge

Abstract

The Mohns and Knipovich mid-ocean ridges in the Arctic Ocean are ideal settings to investigate the dynamics of spreading centers, being the region affected by intricate interplays between oblique plate kinematics and curved plate boundary geometry. Furthermore, significant mantle thermal structure anomalies coexist with basalts having strongly radiogenic Hf isotopes, which suggest a link between mantle heterogeneity and present-day geodynamics. We explore innovative thermo-mechanical numerical models that incorporate the peculiar characteristics of this sector of Arctic Ocean, obtaining along-axis mantle thermal structure variations and across-axis asymmetries that match the observation at Mohns-Knipovich ridge intersection. We show that partial melting processes, magma distribution, and plate reorganization are all influenced by intrinsic parameters such as asymmetric half-spreading rates, non-linear ridge geometry, ridge migration, and pre-existing mantle heterogeneity. Our findings challenge the concept of symmetric oceanic seafloor expansion, highlighting the need for refined models that incorporate regional geodynamics and mantle composition to better understand the evolution of mid-ocean ridges and, ultimately, plate tectonics.