Northeastern YNP and the Grand Canyon of the Yellowstone
Even though Thursday morning dawned grey and drizzly, we got up bright and early for a short hike to see columnar jointing and an outcrop that was evidence of the bimodal magmatism in the park area. Columnar jointing caused by cooling cracks in a basaltic flow.
The polygonal pattern of the jointing is evident from the top of the columns.
During the Yellowstone area volcanism, trees were buried in deep layers of pyroclastic ashflow. The trees were preserved upright in the rock in their original orientations. Here, a tree that has remained as the surrounding tuff weathered away.
Just west of the park boundary is an extremely shallow and extremely long-running fault, or decollement. The Heart Mountain Detachment Fault is visible in this picture as it cut through a weak limestone layer (the white line in the rocks.
Of course, no field trip would be complete without some van trouble. Fortunately, there was only a funny smell that turned out to be nothing.
After driving around all day, our last stop made up for it all--the Grand Canyon of the Yellowstone. This is an area where the Yellowstone River has cut a deep canyon for itself. The yellow- tinted rhyolites that gave the river its name line the canyon walls. Eric discusses river downcutting.
The Lower Falls, one of two spectacular drops in the river caused by the caldera rim.
Chris contemplates the scene while hanging from a tree.
Peter and Rachel for scale against the yellow canyon walls.
Even though Thursday morning dawned grey and drizzly, we got up bright and early for a short hike to see columnar jointing and an outcrop that was evidence of the bimodal magmatism in the park area. Columnar jointing caused by cooling cracks in a basaltic flow.
The polygonal pattern of the jointing is evident from the top of the columns.
During the Yellowstone area volcanism, trees were buried in deep layers of pyroclastic ashflow. The trees were preserved upright in the rock in their original orientations. Here, a tree that has remained as the surrounding tuff weathered away.
Just west of the park boundary is an extremely shallow and extremely long-running fault, or decollement. The Heart Mountain Detachment Fault is visible in this picture as it cut through a weak limestone layer (the white line in the rocks.
Of course, no field trip would be complete without some van trouble. Fortunately, there was only a funny smell that turned out to be nothing.
After driving around all day, our last stop made up for it all--the Grand Canyon of the Yellowstone. This is an area where the Yellowstone River has cut a deep canyon for itself. The yellow- tinted rhyolites that gave the river its name line the canyon walls. Eric discusses river downcutting.
The Lower Falls, one of two spectacular drops in the river caused by the caldera rim.
Chris contemplates the scene while hanging from a tree.
Peter and Rachel for scale against the yellow canyon walls.