Geology Stops

Listed below are the best locations to view and understand Mesa Verde National Park geologic features. Wayside exhibits and trail guides will assist you in interpreting the park geology. Our brief description of park geology in this page should give you a good understanding of the park's geology before you arrive.

Geologic Overlook is a stop along the main park road. A short walk on the trail from the parking area will lead you to the overlook and soon to be installed wayside exhibits that discuss the area geology as well as other park topics.

Knife Edge Trail (1.5 miles) is accessed in Morefield Campground. Take along the trail guide to learn about area geology, and other park topics as well.

Montezuma Overlook is a stop along the main park road. The overlook has soon-to-be-updated exhibits that discuss area geology and other park topics as well.

Park Point is the highest point on the main park road. A short walk on the trail from the parking lot will lead you to the overlook and wayside exhibits. These exhibits discuss area geology and other park topics as well.

Petroglyph Loop Trail (2.8 miles) is located near the museum and Spruce Tree House. Take along the trail guide to learn about area geology as well as other park topics.

Spruce Tree House Trail (0.5 miles) is located near the museum. Take along the trail guide to learn about area geology and other park topics as well.

Geology

(The following information is taken from a book by Mary O. Griffitts entitled Guide to the Geology of Mesa Verde National Park. This book is available for sale from the Mesa Verde Museum Association for $5.95)

The sequence of rocks exposed on the mesas originated in a great inland sea that began to cover this area about 100 million years ago. As the water encroached over a low, relatively flat erosion surface, streams from the west brought sands and muds into the shallow water. These shoreline deposits consisted of beach sands, shallow water cross-bedded shore sands, lagoonal and swamp muds, and deltaic sands at the mouths of inflowing streams. These deposits are now the brown Dakota Sandstone seen in the Cortez Valley below the Mesa Verde. This particular layer is not exposed within the boundaries of Mesa Verde National Park.

The sea continued to advance until the Mesa Verde region was far out from the shoreline that was probably close to what is now the western edge of Utah, some 200 miles away. The sediments deposited change from the coarser, near shore, sandy deposits to fine, evenly bedded shales. In all, about 2,000 feet of Mancos Formations were deposited in quiet offshore conditions, and is now exposed in the steep, dark gray shale slopes of the north escarpment. Although the Mancos Shale appears to be a great shale mass, it is not one homogeneous unit. The sediments were deposited over a ten million year period and consist primarily of shales with some limestones. It took over 10 million years to deposit the 2,000 feet that make up the Mancos Formation. Variations in environments throughout time are well documented in rock types and in an abundant and varied fossil record. The sea reached its greatest extent during the deposition of the Mancos Shale, and then began a slow withdrawal. The Mancos Shale is visible as visitors drive into the park from the entrance station to approximately Mile Post 4 near the Morefield Campground.

Overlying the thick Mancos Formation is the Mesa Verde Group of formations. This group is subdivided into three formations; from the oldest, the Point Lookout Sandstone, to the Menefee Formation, to the Cliff House Sandstone, which is the youngest. The Point Lookout Sandstone is seen as visitors travel from Morefield Campground through the tunnel on the main road and then through Prater Canyon. As one travels through the switchbacks past the Montezuma Valley Overlook, exposures of the Menefee Formation become evident. Finally, upon reaching the Far View Visitor Center, the Cliff House Sandstone is the predominant formation visible.

Sand was brought into the sea, the water became shallower, and the shales became progressively sandier. The massive shallow water Point Lookout Sandstone overlying and grading into the Mancos Formation was named for the prominent Point Lookout overlooking the flat plain. Few fossils remain in this formation because sediments were deposited in a zone of vigorous wave and current action.

The sea continued to withdraw to the northeast, and a broad, low coastal plain emerged. Woody shales, coals, and coarse irregular sands were deposited in broad, shallow swamps and along stream and inter stream areas and became the sediments of the Menefee Formation. Many plant fossils are evidence of lush vegetation and show that the climate was wet and warm during this period when the land was only slightly above the sea.

The sea again lapped farther south. Beach sands and shallow water sands were then deposited, forming the Cliff House Formation which now caps the mesa. This formation takes its name from the presence of the famous cliff dwellings in the alcoves and niches weathered in these sandstones. The alcoves are formed by the action of the ground water percolating through the porous sandstones until it reaches an impervious layer and then moves along this water barrier to the canyon edge. Freezing, thawing, chemical, mechanical, and wind erosion all continue to enlarge the niches along the canyon walls. The Cliff House Formation contains many invertebrate and vertebrate fossils. Most of the vertebrate remains were broken due to wave action at the time of deposition. The fossils near the top of the formation have been dated at approximately 87.5 million years old.

Uplift of the area at the end of the Cretaceous Period drained the sea and initiated a long period of erosion which gave rise to the present topography. Laccolithic igneous intrusions gave rise to the La Plata Mountains to the north and Ute Mountain to the west. Much of the flat mesa surface of the Mesa Verde and the Cortez Valley are covered with varying depths of red wind blown soil (loess) which has been accumulating for one million years.

For a more detailed explanation of Mesa Verde geology and geologic features, go to Geology of Mesa Verde. (Adobe PDF) You can download the required Free Adobe Reader from http://www.adobe.com/products/acrobat/readstep2.html.