|The Grand Canyon of the Yellowstone River is carved in volcanic rocks erupted about 640,000 years ago|
They asked me to write a short post on volcanism near Yellowstone. I was fortunate to spend much time there about ten years ago, becoming familiar with many of the geologic features there. You can read my posting on Yellowstone volcanism here. The introductory article for the US Highway 89 web site can be read here. I have also written geologic summaries of the three geographic provinces that US Highway 89 traverses. The Basin and Range article can be read here. The Colorado Plateau article is found at this link. And the article describing the geology of the Rocky Mountain Province is here. The Cowlin's are to be commended for celebrating the beauty and heritage of this incredible western highway.