Prehistory of Colorado
As the natives became more sedentary, there were significant technological and social advances, including basket, pottery, and tool making, and creation of permanent structures and communities.
Wind, gravity, rainwater, snow, and ice-melt supplied rivers that ultimately carved through the granite mountains and eventually led to their end.
[2]: 6 Fountain Formation is Pennsylvanian bedrock unit consisting primarily of conglomerate, sandstone, or arkose, in Colorado and Wyoming, along the east side of the Front Range of the Rocky Mountains, and along the west edge of the Denver Basin.
[2]: 8 Related sites include: Garden of the Gods, Roxborough State Park, and the Lyons and neighboring Hall Ranch Open Space areas.
The sediment deposition of wavy layers of muddy limestone and signs of stromatolites that thrived in a smelly tidal flat at present-day Colorado.
Colorado eventually drained from being at the bottom of an ocean to land again, giving yield to another fossiliferous rock layer, the Denver Formation.
[2]: 16 Related sites are: Garden of the Gods, Fountain Creek Nature Center, Rooney Road near Dinosaur Ridge, Valmont Dike Fox Hills Formation was formed during the Paleogene / Cretaceous periods.
It is a marginal marine yellow sandstone with shale interbeds[3] created with the receding Western Interior Seaway in Late Cretaceous time.
[4][5][6] Denver Formation, formed during the Paleogene / Cretaceous periods 55 million years, contains fossils and bones from dinosaurs like Tyrannosaurus rex and Triceratops.
An uplift occurred on the Front Range that caused the Pikes Peak granite to become exposed and then erode on the surface, resulting in a white sandstone called Dawson Arkose.
[2]: 26 Related sites are: Castlewood Canyon State Park, Molly Brown House Museum, Rocks Park and mesa tops between Castle Rock and Monument Hill The White River Formation is found in the Northeastern corner of the Colorado, and was deposited between ~37.2 and ~30.8 Ma, encompassing parts of the late Eocene and early Oligocene.
The formation is composed primarily of claystones, mudstones, and siltstones, within which a variety of fossil organisms, collectively referred to as the White River fauna, can be found.
The fossil assemblage of the formation includes tortoises, alligators, predatory birds, Perissodactyls such as primitive horses and rhinoceroses, Entelodonts, Nimravids, rodents, Artiodactyls, and other mammals.
However, as seen before, life rebounds, and after a few million years mass floods cut through the rhyolite and eroded much of it as plants and animals began to recolonize the landscape.
About 10 million years ago, the Front Range began to rise up again and the resistant granite in the heart of the mountains thrust upwards and stood tall, while the weaker sediments deposited above it eroded away.
The receding glaciers and warming into an Ice Age summer created a climate suitable to camelops, mastodon, mammoth, bison antiquus and other megafauna.
[2]: 30 Related sites: Carson Nature Center, Highlands Ranch Open Space, Sand Creek Drainage, South Platte Park Paleoclimatology is the study of prehistoric weather.
[8]: 10–13 The Denver Museum of Nature and Science developed an eight-zone classification of ecosystems, defined primarily by the most present dominant plant life:[8]: 17 Since the Precambrian eon, the land forms have lifted, receded and have been eroded; global temperature has vacillated from tropical to ice age,[2]: 1–2 which significantly affected the number and type of ecosystems and what animal and plant life flourished during each geological period.
[11]: 53–54 An example is Lamb Spring in Littleton, with mammoth bones dated 14,140 to 12,140 years ago and hunting by use of stone tools other than Clovis points.
The bison antiquus had become extinct, like the other megafauna, and people became reliant on smaller game, such as deer, antelope and rabbits, and gathering wild plants.
Their tool kits became larger, with greater reliance on manos and metates to grind food and changes in weapons for hunting, such as notched projectile points.
[14]: 33–34 Archaic–Early Basketmaker Era (7000–1500 BC) was a cultural period of ancestors to the Ancient Pueblo People, represented in Colorado only in the southwestern past of the state.
They were a tradition of hunter gatherers who sometimes farmed and lived in northern New Mexico or southern Colorado in rockshelters, single or multi-room stone or slab structures or in campsites.
[23] They were named "Basketmakers" for their skill in making baskets for storing food, covering with pitch to heat water, and using to toast seeds and nuts.
[24]: 27–30 [25] During the Late Basketmaker II Era (AD 50 to 500), people living in the Four Corners region were introduced to maize and basketry through Mesoamerican trading.
[24]: 39–45 [27][28] Rohn and Ferguson, authors of Puebloan ruins of the Southwest, state that during the Pueblo III period (AD 1150 to 1300) there was a significant community change.
Some bands practiced seasonal agriculture along the upper Arkansas River, cultivating squash, beans, pumpkins, melons, peas, wheat, and corn.
[11]: 244–248 [31] The ancestors to the Navajo were one of the tribes of the southern division of the Athabaskan language family that migrated south from Alaska and northwestern Canada, most likely traveling through the Great Basin.
it is generally believed that the migration of the Ute was in part an effort to separate themselves from other Shoshonean speaking tribes, such as Shoshone Bannock, Paiute, Comanche, Goshute, and Chemehuevi.
Between about 1820 and 1830 the Arapaho and Cheyenne, who had arrived from the northeast, pressed down the eastern side of Colorado pressuring the Comanche to the south, below the Arkansas River.
