Tests of fixity of the Indo‐Atlantic hot spots relative to Pacific hot spots

Abstract

Rates of inter-hot spot motion have been debated for decades. Herein we present updated predictions for the tracks of the Tristan da Cunha, Réunion, and Iceland hot spots assuming them to be fixed relative to Pacific hot spots. Uncertainties in Pacific hot spot rotations, which include uncertainties in the current locations of hot spots of 100-200 km, are combined with uncertainties in relative plate motions accumulated through the plate circuit to obtain the final uncertainty in the predicted positions (including uncertainties of 150-200 km in the current locations of the Indo-Atlantic hot spots). Improvements to reconstruction methods, to relative plate reconstructions, to age dates along the tracks, and to the geomagnetic reversal timescale lead to significant changes from prior results. When compared with the observed tracks, the predicted tracks indicate nominal rates of motion of only 2-6 mm a À1 of these Indo-Atlantic hot spots relative to Pacific hot spots over the past 48 Ma. Within the uncertainties, the rates range from no motion to rates as high as 8-13 mm a À1. For reconstructions prior to 48 Ma B.P., however, the apparent rates of inter-hot spot motion are much larger, 46-55 ± 20 mm a À1, if the motion occurred entirely between 68 Ma B.P. and 48 Ma B.P. Either hot spots moved rapidly before 48 Ma B.P., and slowed drastically at ≈ 48 Ma B.P., or global plate circuits through Antarctica become less reliable as one goes increasingly further into the past. Most paleomagnetic data favor the latter explanation.

Assessing Models for Pacific Absolute Plate and Plume Motions

“…The H2016 model explicit drift rate for Hawaii is considerably higher than that of the D2012 explicit rates, by a factor of 2. (3) All implicit mean plume drifts exceed observational speed limits for the post‐HEB era (Koivisto et al, ) as well as inferred hot spot drift rates for the last ~5 Myr (Wang et al, ).…”

Paleolatitude of the Hawaiian Hot Spot Since 48 Ma: Evidence for a Mid‐Cenozoic True Polar Stillstand Followed by Late Cenozoic True Polar Wander Coincident With Northern Hemisphere Glaciation

“…Figure b also shows the 10‐ to 40‐Ma poles from the continents (Torsvik et al, ) reconstructed into the Pacific hot spot reference frame using the same plate reconstruction parameters as those used by Koivisto et al (), except that herein we incorporate the motion between East and West Antarctica estimated by Granot et al (). The poles reconstructed from the continents are compared with the 12‐ to 48‐Ma mean location of the spin axis relative to Pacific hot spots.…”

“…Our analysis indicates that during formation of most of the Hawaiian chain (i.e., from 48 to 12 Ma), the motion of the Hawaiian hot spot relative to the spin axis was insignificant, merely 3 ± 5 mm/a (95% confidence limits). Over this interval other Pacific hot spots have evidently moved little relative to one another (Wessel & Kroenke, , ) and have been approximately fixed relative to global hot spots with little or no significant motion (Koivisto et al, ; Wang et al, ). Therefore, global hot spots were nearly stationary relative to the spin axis from 48 to 12 Ma, indicating a stillstand in TPW that lasted ≈36 Ma.…”

Observational Test of the Global Moving Hot Spot Reference Frame

“…In contrast, to explain the track of the Emperor chain (≈50–80 Ma) on the Pacific plate, several studies found that the velocity of the Hawaiian hot spot was as high as 40 to 80 mm/a in early Cenozoic and Late Cretaceous time (Konrad et al, ; Norton , ; Raymond et al, ; Tarduno et al, ). Morgan (), Duncan (), and Koivisto et al () have argued, however, that the high apparent velocity of the Hawaiian hot spot during the formation of the Emperor chain is an artifact of missing motion in the global plate motion circuit, most likely due to unmodeled motion between East and West Antarctica, as seems required by paleomagnetic data (Gordon & Cox, ; Acton & Gordon, ; but see a differing opinion in Doubrovine & Tarduno, ).…”