Paper No. 7
Presentation Time: 2:35 PM
SPATIOTEMPORAL ASSOCIATION OF LARGE IGNEOUS PROVINCES AND MOBILE LARGE LOW SHEAR VELOCITY PROVINCES THROUGHOUT THE LAST SUPERCONTINENT CYCLE
The lowermost mantle is currently dominated by two large, approximately antipodal structures that may be compositionally distinct from their surroundings termed Large Low Shear Velocity Provinces (LLSVPs). On the basis of laboratory and numerical experiments, the LLSVPs are expected to shift over time as they are drawn under upwellings and pushed away from downwellings. It has been suggested that because the LLSVPs in general and the boundaries of the LLSVPs in particular appear to correlate well with the reconstructed eruption locations of large igneous provinces and kimberlites and with the present-day locations of hot spots with a deep mantle origin, the piles have been relatively stationary since the assembly of Pangea. We use global mantle convection simulations driven by surface velocity boundary conditions based on Phanerozoic plate reconstructions to explore the relationship between the spatial and temporal distributions of plumes rising from the lower mantle, the LLSVPs, and Earth’s volcanic record. We find that the plumes in our numerical models are spatially associated (though not exclusively so) with the LLSVPs. The correlation between the reconstructed eruption locations of large igneous provinces and the boundaries of the dynamically-evolving LLSVPs in our models is much stronger than we would expect by chance, suggesting that the chemical piles need not be spatially fixed to account for the spatial distribution of LIP eruption locations.