Waned mantle upwelling contributes to a heavily deformed northern smooth plains on Mercury

Recent advancements in mapping and interpretation have revealed both numerous contractional landforms and evidence that tectonic activity has persisted into geologically recent times in Mercury's northern smooth plains (NSP). To investigate the mechanisms behind these observations, we conduct a comprehensive assessment of contractional strain across the NSP. Our analysis reveals that (1) the NSP exhibits higher strain than other terranes on Mercury, and (2) the surface deformation pattern is spatially correlated with the Northern Rise (NR) at the center of the NSP, suggesting an additional driving force. We propose that this elevated strain and its distribution result from waned mantle upwelling induced by deep mantle flow beneath the NR. Sustained variations in dynamic topography likely fueled the long-standing tectonism in the NSP. These findings provide a complementary perspective on Mercury's evolutionary history and may help illuminate similar processes on other terrestrial planets.