Analysis of Pacific Hotspot Chains

Abstract

Seamount trails created by mantle plumes are often used to establish absolute reference frames for plate motion. When plume drift is considered, changes in seamount trail direction and age progression cannot be attributed to plate motion change alone. Here, improvements to age-progressive models of eleven Pacific hotspot chains are made independently of plate motion models. Our approach involves bathymetry processing to robustly predict a smooth, continuous hotspot path by connecting maxima in filtered seamount bathymetry, with across-track uncertainties from seamount trail width and amplitude. Published ages from seamount samples are projected orthogonally onto these paths. We determine best-fit models of age as functions of along-track distance, giving continuous age-progression models for each seamount chain with uncertainties in age and geometry. Different sources of paleolatitudes are examined by incorporating data from the magnetization of seamount drill-core samples, paleo-poles from marine magnetic anomaly skewness inversions, and paleo-spin-axes inferred from shifts of equatorial sediments. Improved paleolatitude models for the Hawaiian-Emperor and Louisville chains are determined by combining these different types of data. Paleolatitude models are predicted for other chains during periods when sufficient amounts of paleo-pole or paleo-spin-axis data are available. Analysis of the eleven Pacific seamount chains provide constraints for future plate and plume motion models. We analyze the temporal change in distance between coeval seamounts, reflecting relative drifts between the hotspots at different times in the past. The observed changes imply systematic relative hotspot drifts compatible with paleolatitude trends.