I'll mention this as it's big in the brochures and we saw a lot of signs pointing to parking lots. We didn't attend a performance, nor stop by to see if we could just look the place over. I hear great things, but I think it's better if you like the performers that come to this stage.
"Who Made these tracks"
Lisitng of stops:
Rooney Ranch, Western Interior seaway, Mangrove Swamp, Dinosaur Tracks, Trace Fossils, Ecology, Ripple Marks, Coal & Clay Mining, Hogback, Denver basin, Oil & gas, Cretaceous Time, Geologica Puzzle, Volcanic Ash, Geologic Overview, Faults, Brontosaur Bulges, Jurassic Time, Dinosaur Bone Quarry
Approximately 100 millino years ago, when this area was part of the coastal plain of the Cretaceous Western Inteior Seaway, at least two quite different types of dinosaurs passed this way. The most common kind left large, broad, therr-toed tracks of its hind feet and smaller crescent-shaped tracks of its front feet. It was probably an ornithopod like Iquanodon, or something similar. The dinosaur could walk on either two legs or four legs and was a herbivoir. The second kind of dinosaur was a small carnivorous theropod, perhaps resemlbing an Ornithominus or galliminus. It was about the size and shape of a modern emu or ostrich. Also, like such large bround birds, it walked onjly on its hind feet, each of which had three slender toes tipped with pointed claws.
"What is a Hogback?"
Dinosaur Ridge is part of the Dakota Hogback, the prominent ridge that parallels the mountain front in much of Colorado and is particularly well developed here. The term "hogback" is used in geology to refer to settp, narrow ridge somewhat like the back of a Arkansas razorback hog. Hogbacks form in layered rocks of variable harness that have been tilted. The softer layers are eroded more rapidly thant he mroe resistant ones leaving the harder layers standing as ridges above the softer rocks in the slopes and intervening valleys. The resistant layer that is the 'backbone' or 'hogback' of Dinosaur Ridge is the Dakota sandstone. About 100 million years ago, it was a shoreline sand where dinosaurs walked and left their footprints. The sand has since been cemented into the hard, resistant sandstone sandwiched between softer mudstones (shale). Beginning about 65-70 million years ago, mountani building forces uplifted the rocks to our west, bowing the layered sedimants over the mountain core. Since then, erosion has stripped away great thicknesses of overlying rock, exposing the granite and gneiss in the core. The Dakota Hogback, of which Dinosaur Ridgeis a part is an erosional remnant of the upturned layers preserved along the mountain front.
"Volcanic Ash Bed"
Interbedded with the sandstones and shales behind this sign is a thin white layer of volcanic ash that was deposited during a volcanic eruption northwest of present-day Colorado. Crystals of mineral zircon in this volcanic ash were used to date these rocks. Scientist at the United States Geological Survey calculated the age of the ash to be 105.6 [+/- 1.3] millino years old or early Cretaceous in geological time scale.
The age of the ash layer was determined by using a radiometric dating technique. The tiny crystals of zircon in the ash contain radioactive uranium. Because uranium decays to form lead at a constant, well known rate, scientists were able to calculate how long ago the zircon crystals formed by measuring the relative amounts of uranium and lead that arein the zircon today.
The age, derived radiometrically, is consisten wtih earlier ages derived from the fossil record.
Find the white layer of ash!
"Inverted Dinosaur tracks"
Morrison Fossil Area
has been designated a
This site possesses exceptional value as an illustration of the Nation's Natural Heritage and contributes to a better understanding of the Environment
National Park Service
United States Department of the Interior