Page "Rodinia" Paragraph 19

Low temperatures may have been exaggerated during the early stages of continental rifting.

Geothermal heating peaks in crust about to be rifted ; and since warmer rocks are less dense, the crustal rocks rise up relative to their surroundings.

This rising creates areas of higher altitude, where the air is cooler and ice is less likely to melt with changes in season, and it may explain the evidence of abundant glaciation in the Ediacaran period.