These rocks are considered to be glacial diamictites from the Early Proterozoic Libby Creek Group in the Snowy Mountains of the Southern Rocky Mountains. The white blobs are the clasts that fell into muddier sediment now turned into schist by metamorphism. These rocks were deposited at a time when the Earth's atmosphere was changing, with increases in oxygen and possibly a reduction in greenhouse gases like methane and carbon dioxide. Other localities of this age also suggest glaciation, indicating this might be a worldwide event.