In another room of the cave, there was a contact between dirty ice (center of the picture) and clean ice (top third). You can also see some of the dirt on the floor of the cave (bottom third of the picture) and a bit of running water. The dirty ice may have been really old ice that fell as snow during a dustier period of the region's history (>10,000 years ago) or it could have been ice that was trasported along the bed of the glacier for a ways, picking up sediment as it went.