Adrian Lenardic
Summary: 180 million years ago Earth’s continents were amalgamated into one supercontinent called Pangaea. Analysis of oceanic crust formed since that time suggests that the cooling rate of Earth was enhanced in the wake of Pangaea’s dispersal.
Figure- a, Pangaea existed between about 300 and 175 million years ago. While in place, the supercontinent may have had an insulating effect on the ambient mantle (blue circles), creating a warm mantle anomaly (red circle). b, This anomaly may have destabilized Pangaea and caused the supercontinent to break apart, thus forming the Atlantic and Indian oceans. With the break-up, hot mantle stored beneath the supercontinent delivers a pulse of high heat flux and melt production to adjacent mid-ocean ridges. Such anomalies can take up to 100 million years to dissipate, leading to the formation of locally thicker oceanic crust at the surface and an increased planetary cooling rate. Van Avendonk and colleagues3 show that thickened crust preserved in the Atlantic and Indian oceans, compared to the Pacific Ocean, preserve a record of the insulating effect of Pangaea. Figure modified from ref. 8; Geological Society of America.
Full article: http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2862.html
Nature Geoscience (2016) doi:10.1038/ngeo2862
Published online 12 December 2016
