Dinosaur National Monument, on the Colorado–Utah line, was created in 1915 for one wall of rock: the Dinosaur Quarry, where more than 1,500 dinosaur bones lie exposed — one of the greatest Jurassic fossil sites in the world. Around it, the Green and Yampa Rivers have cut some of the finest canyons in the American West through rocks spanning more than a billion years.
The Geologic Resources Inventory report for the monument. NPS
The quarry
Made famous by Earl Douglass and W. J. Holland, the quarry holds three layers of bone:
| Layer | |
|---|---|
| First | dug out mostly in the early 1900s for museums |
| Second | uncovered and prepared in place, so visitors see the bones where they lie |
| Third | still largely undeveloped |
The bones are in the Morrison Formation of the Late Jurassic, one of the best records of life on land in the age of dinosaurs: Allosaurus, Apatosaurus, Diplodocus, Camarasaurus and Stegosaurus among them.
Far more than dinosaurs
Sixteen rock formations in the monument, from the Cambrian to the Cretaceous, carry fossils: foraminifera, petrified wood and plants, charophytes, bryozoans, sponges, crinoids, ostracodes, trilobites, mollusks, and vertebrates — fish, turtles, frogs, meat-eating theropods, long-necked sauropods, plant-eating ornithopods, and mammals — as well as fossil tracks. All of it is protected by the Paleontological Resources Preservation Act of 2009.
How the landscape was built
- The Uinta Mountains. The monument sits at their eastern end, on a broad upward fold (an anticline) raised in the Laramide Orogeny, about 70 to 40 million years ago. Its faults and folds are among the best exposed anywhere in the Rocky Mountains.
- Colour. Rock from the Precambrian to the present wears away at different rates, leaving bands of colour and a variety of landforms.
- Canyons. The Green and Yampa Rivers carved the Canyon of Lodore, Yampa Canyon, Split Mountain, Whirlpool Canyon and Jones Hole. Lodore and Yampa are counted among the greatest river gorges in western North America.
- Province. The monument is part of the Colorado Plateaus.
The Green River in Dinosaur National Monument. NPS
Caves, soils and old mines
| Caves | at least five; 13 limestone and other carbonate units could hold karst, which underlies 39% of the monument. Whether they hold karst aquifers, springs or cave-only invertebrates is unknown. The monument has 14 bat species; whether they use the caves is not known either |
| Soils | 77 soil map units and 80 soil types. The clay-rich Bodry, Deaver, Chipeta, Hanksville and Massadona soils swell and shrink enough to damage buildings and roads |
| Abandoned mines | can be habitat and history — and dangerous. Stay out and stay alive |
Caves are protected by the Federal Cave Resources Protection Act of 1988.
Maps and reports
The NPS Geologic Resources Inventory has a scoping summary, a digital geologic map, a report and a poster, and a Soil Resources Inventory is complete; both are in the NPS DataStore (saved searches 2812 and 2827).
The monument's digital geologic map. NPS
Sources
Written from "NPS Geodiversity Atlas—Dinosaur National Monument, Colorado and Utah," Geologic Resources Division, National Park Service; a work of the United States government in the public domain. It cites Graham (2006) and Gregson and Chure (2000).
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