Taking the temperature of ancient earth

A team of researchers, including earth and planetary scientists from Washington University in St. Louis, for the first time has been able to reconstruct both ocean temperature and general ice thickness of massive glaciers during one of the biggest mass extinctions in history hundreds of millions of years ago. The extinction, which occurred between 445 and 443 million years ago in the Late Ordovician Period, is one of the five biggest mass extinctions in Earth history, wiping out an estimated 75 percent of simple marine species.