Chaco Culture National Historical Park, San Juan County, New Mexico, USAi

Regional Level Types
Chaco Culture National Historical Park	Canyon
San Juan County	County
New Mexico	State
USA	Country

During the Cretaceous Period about 85 to 75 million years ago the land that is now Chaco Canyon was located on the western edge of the Western Interior Seaway. While tectonic forces were building the Rocky Mountains during the Laramide Orogeny the land to the east of the mountains subsided creating the San Juan Basin. The San Juan Basin filled with sea water forming a seaway that extended from the Arctic Ocean to the Gulf of Mexico. As sea levels fluctuated both deep-water sediments and beach sediments were deposited. During this process barrier islands formed and some terrestrial sedimentation was added to the mix.

Today there are two geological formations that are exposed throughout the canon. The Cliff House Sandstone is part of a barrier island in the seaway and the Menefee Formation (primarily shale) was formed from swamp, lagoon, and stream channel sedimentation. The Lewis Shale (deep water sediment) and the Pictured Cliffs Sandstone (delta, beach, and stream channel sediments) are exposed near the northern boundary of the park.

Chaco Canyon is known for the extensive pre- Columbian pueblo ruins that dot the canyon floor. In 1907 Theodore Roosevelt set aside this land as the Chaco Canyon National Monument. In 1980 the name was changed to the Chaco Culture National Historical Park.

Fossils

There are 4 fossil localities from the PaleoBioDB database within this region.

BETA TEST - These data are provided on an experimental basis and are taken from external databases. Mindat.org has no control currently over the accuracy of these data.

Occurrences	31
Youngest Fossil Listed	61.7 Ma (Paleocene)
Oldest Fossil Listed	83.5 Ma (Late/Upper Cretaceous)
Stratigraphic Units	Unit No. Occurrences Age Nacimiento 8 63.3 - 56 Ma (Paleocene) Kirtland 2 70.6 - 66 Ma (Late/Upper Cretaceous) Kirtland - Hunter Wash 1 83.5 - 70.6 Ma (Late/Upper Cretaceous) Fruitland 1 83.5 - 66 Ma (Late/Upper Cretaceous) Fruitland/Kirtland 19 83.5 - 70.6 Ma (Late/Upper Cretaceous)
Fossils from Region	Click here to show the list.
Accepted Name Hierarchy Age Osteichthyes unranked clade Animalia : Chordata : Osteichthyes 83.5 - 70.6 Ma Late/Upper Cretaceous Crocodylia unranked clade Animalia : Chordata : Reptilia : Crocodylia 83.5 - 70.6 Ma Late/Upper Cretaceous Compsemys genus Animalia : Chordata : Reptilia : Testudines : Compsemydidae : Compsemys 66 - 61.7 Ma Paleocene Trionyx genus Animalia : Chordata : Reptilia : Testudines : Trionychidae : Trionyx 66 - 61.7 Ma Paleocene Emys genus Animalia : Chordata : Reptilia : Testudines : Emydidae : Emys 66 - 61.7 Ma Paleocene Tyrannosauridae family Animalia : Chordata : Reptilia : Dinosauria : Tyrannosauridae 83.5 - 70.6 Ma Late/Upper Cretaceous Hadrosauridae family Animalia : Chordata : Reptilia : Dinosauria : Hadrosauridae 83.5 - 70.6 Ma Late/Upper Cretaceous Ceratopsia unranked clade Animalia : Chordata : Ornithischia : Ceratopsia 83.5 - 70.6 Ma Late/Upper Cretaceous Ceratopsidae family Animalia : Chordata : Reptilia : Dinosauria : Ceratopsidae 83.5 - 70.6 Ma Late/Upper Cretaceous Dinosauria order Animalia : Chordata : Reptilia : Dinosauria 83.5 - 70.6 Ma Late/Upper Cretaceous Coelurosauria suborder Animalia : Chordata : Saurischia : Avetheropoda : Coelurosauria 83.5 - 70.6 Ma Late/Upper Cretaceous Carnosauria unranked clade Animalia : Chordata : Saurischia : Avetheropoda : Carnosauria 83.5 - 70.6 Ma Late/Upper Cretaceous Testudines order Animalia : Chordata : Reptilia : Testudines 83.5 - 70.6 Ma Late/Upper Cretaceous Hutchemys acupictus species Animalia : Chordata : Reptilia : Testudines : Plastomenidae : Hutchemys : Hutchemys acupictus 66 - 61.7 Ma Paleocene Trionyx singularis species Animalia : Chordata : Reptilia : Testudines : Trionychidae : Trionyx : Trionyx singularis 66 - 63.3 Ma Paleocene Bistahieversor sealeyi species Animalia : Chordata : Saurischia : Avetheropoda : Bistahieversor : Bistahieversor sealeyi 83.5 - 70.6 Ma Late/Upper Cretaceous Hoplochelys crassa species Animalia : Chordata : Reptilia : Testudines : Kinosternoidea : Hoplochelys : Hoplochelys crassa 66 - 61.7 Ma Paleocene Pantrionychidae unranked clade Animalia : Chordata : Reptilia : Testudines : Pantrionychidae 66 - 61.7 Ma Paleocene
Fossil Localities	Click to show 4 fossil localities

References