Fig. 6: Comparisons between reference frames with glendonite and crocodilian proxy data.
From: Polar wander leads to large differences in past climate reconstructions
Comparisons are for (a) the Middle-Early Jurassic and (b) the Middle-Late Eocene. Distributions of glendonites40 and crocodilians (https://paleobiodb.org) are plotted on simulated surface air temperatures. The pure paleomagnetic reference frame23 is shown on the top row, with the hybrid mantle reference frame second row21. The differences between simulated air temperatures and latitudinal positions, reconstructed to the present day, are shown in the third and fourth rows. Blue areas indicate regions where the pure paleomagnetic frame is cooler or closer to the poles, and red areas indicate regions where the pure paleomagnetic frame is warmer or closer towards the equator. Crocodilian distributions constrain warm climates with mean annual temperatures above 14.2°44, historically limited to low-mid latitudes65. Glendonites, believed to form in cool water between -2 and 7 °C42, are thus constrained to higher latitudes and cooler regions. The simulated climate in the paleomagnetic frame places glendonites in cooler climates with less variance compared to the mantle frame. Also see Fig. S24 for this data in an orthographic projection.
