But the exact periods in history when it happened ... An estimated 90 percent of all animal species on the Earth were wiped out. Many groups of insects and mammal-like reptiles disappeared.

All three of orbital cycles — called Milankovitch ... Model, proxy and isotopic perspectives on the East African Humid Period. Earth and Planetary Science Letters 307, 103-112 (2011).

While this provides some evidence that at least one part of the continental interior was covered in ice during the snowball Earth period, that doesn't necessarily apply to all areas of all continents.

All of these things happened during Snowball Earth upheaval," Courtney-Davies said. "We have to better characterize this entire time period to understand how we and the planet evolved together." ...