Portal:Geography/Featured article/June, 2006
formations that together represent 150 million years of mostly Mesozoic-aged sedimentation. At various periods in that time, warm, shallow seas, streams, ponds and lakes, vast deserts and dry near-shore environments covered the area. Uplift associated with the creation of the Colorado Plateaus lifted the region 10,000 feet (3000 m) starting 13 million years ago. (more...)