Texas researchers from the University of Houston, Baylor University and Texas A&M University have discovered evidence for why the earth cooled dramatically 13,000 years ago, dropping temperatures by about 3 degrees Centigrade.

The evidence is buried in a Central Texas cave, where horizons of sediment have preserved unique geochemical signatures from ancient volcanic eruptions—signatures previously mistaken for extraterrestrial impacts, researchers say.

The resolution to this case of mistaken identity recently was reported in the journal Science Advances.