Dinosaur National Monument - the flank of a monoclinal

This view is from the Iron Springs Bench Overlook along the Harpers Corner Self-guiding Scenic Drive in the central portion of Dinosaur National Monument. The view shows the flank of a monoclinal (stair-step) fold in sedimentary strata. The hogbacks (near vertical layers eroded into pinnacles) are part of the Pennsylvanian and Permian Weber Sandstone. The red layers on the right are part of younger Mesozoic sedimentary rock formations. (The rocks shown here do not include the Morrison Formation; the rock formation that bears dinosaur fossils known in other sections of the park). The great monoclinal fold formed during the Late Cretaceous to Oligocene Laramide orogeny, long after the sedimentary layers were deposited (Willis, 2000). An orogeny is a mountain building event. Since then, the region has experienced additional periods of uplift and extensive erosion. Today the region is dissected by major rivers (the Green and Yampa Rivers) and their tributary streams (Gregson and Chure, 2000).