Uncertainties in Trends of Young Hot Spot Tracks

Uncertainties in trends of hot spot tracks are investigated using a relationship between trend uncertainty and the mapview dimensions of a hot spot track. Prior estimates of Δt (the time span averaged in estimating the trend of a hot spot track), combined with an observed average track width of σwidth = 33 km, indicate that uncertainties in track trend are larger than estimated before, especially for hot spot tracks on slow‐moving lithosphere. Measured values of σwidth of different hot spot tracks differ insignificantly from one another. Track widths show no significant differences between oceanic and continental tracks and between tracks of deep plumes and tracks of shallow plumes. We find that motion between groups of hot spots on different plates is slow. Nominal speeds vary from 0 to 6 mm/a with a lower bound of zero and upper bounds of 4 to 13 mm/a for the eight best constrained hot spot groups. Plain Language Summary Tracking the rate and direction that tectonic plates move relative to the deep mantle relies on tracking the trends of young volcanic hot spot tracks including the tracks of the Hawaiian, Iceland, and Yellowstone hot spots, which are the surface manifestation of plumes of hot rock that rise from deep in Earth's mantle. The trends of their tracks, which lie atop Earth's crust, are imperfectly known. Their uncertainties can be used to estimate the uncertainties in the rates of motion between hot spots and in the rate and direction of tectonic plate movement relative to the deep mantle. Our method requires knowledge of the width and length of a hot spot track produced in a geologically short time interval (5 to 30 million years). We find no resolvable differences in the widths of different tracks, but the lengths, which are proportional to plate speed relative to the deep mantle, vary considerably. The results indicate that movement between different individual hot spots cannot be resolved. Average relative velocities of hot spots grouped by the tectonic plate on which they reside, however, can be resolved but are low (nominally 0 to 6 km per million years with upper bounds of 4 to 13 km per million years). Key Points Objective uncertainties of trends of hot spot tracks are larger than prior estimates, especially for tracks on slow‐moving lithosphere Small but significant motion occurs between some groups of hot spots; motion between individual hot spots cannot be resolved Widths of hot spot tracks do not vary significantly