Kirtland Formation facts for kids

Kids Encyclopedia Facts

Quick facts for kids Kirtland Formation Stratigraphic range: Campanian (typically Kirtlandian) 75–73Ma PreЄ Є O S D C P T J K Pg N ↓

Type	Geological formation
Sub-units	Hunter Wash, Farmington and De-na-zin Members
Underlies	Ojo Alamo Formation
Overlies	Fruitland Formation
Thickness	594 m (1,949 ft)
Lithology
Primary	Sandstone
Other	Shale, mudstone, conglomerate
Location
Coordinates	36°42′29″N 108°21′00″W / 36.708°N 108.350°W / 36.708; -108.350
Approximate paleocoordinates	42°36′N 76°18′W / 42.6°N 76.3°W / 42.6; -76.3
Region	New Mexico
Country	USA
Extent	San Juan Basin
Type section
Named for	Kirtland Post Office
Named by	C.M. Bauer
Year defined	1916

The Kirtland Formation (originally the Kirtland Shale) is a sedimentary geological formation.

Description
History of investigation
Stratigraphy
Vertebrate paleofauna
Images for kids
See also

Description

The Kirtland Formation is the product of alluvial muds and overbank sand deposits from the many channels draining the coastal plain that existed on the inland seashore of North America, in the late Cretaceous period. It overlies the Fruitland Formation. It is found in the San Juan Basin in the states of New Mexico and Colorado, in the United States of America.

The base of the Kirtland Formation and its lowest sub-unit, the Hunter Wash member, has been dated to 75.02 ± 0.13 Ma. Together with the upper part of the underlying Fruitland Formation, this contains fossils representing the Hunter Wash local fauna. The border between the Hunter Wash member and overlying Farmington member dates to approximately 74 million years ago. The top of the Farmington member and bottom of the overlying De-na-zin member has been radiometrically dated to 73.37 ± 0.28 Ma ago. The top of the De-na-zin member, which contains the Willow Wash local fauna, has been dated to 73.04 ± 0.25 Ma ago.

Overlying the De-na-zin member is a unit called the Naashoibito member This has often been considered to be part of the Kirtland formation, but more recently has been transferred back to the overlying Ojo Alamo Formation, which it had originally been part of.

History of investigation

The formation was named by C.M. Bauer in 1916 for exposures near the Kirtland Post Office.

Stratigraphy

Upper Cretaceous stratigraphy of the San Juan Basin

Vertebrate paleofauna

Crurotarsans

Crurotarsans of the Kirtland Formation
Genus	Species	Location	Member	Abundance	Notes	Images
Brachychampsa	B. montana		De-na-zin		Member of the Willow Wash local fauna.	Brachychampsa
Denazinosuchus	D. kirtlandicus		De-na-zin		Member of the Willow Wash local fauna.
Leidyosuchus	Indeterminate		De-na-zin		Member of the Willow Wash local fauna.

Ornithischians

Ornithischians reported from the Kirtland Formation
Genus	Species	Location	Member	Material	Notes	Images
Ahshislepelta	A. minor		Hunter Wash	Incomplete postcranial skeleton		Kritosaurus navajovius Parasaurolophus tubicen Pentaceratops sternbergii Sphaerotholus goodwini Stegoceras novomexicanum Terminocavus sealeyi Titanoceratops ouranos Ziapelta sanjuanensis
Anasazisaurus	A. horneri			"Partial skull."
Kritosaurus	K. navajovius		De-na-zin		Member of the Willow Wash local fauna.
Naashoibitosaurus	N.ostromi		De-na-zin	"Partial skull."	Member of the Willow Wash local fauna.
Nodocephalosaurus	N. kirtlandensis		De-na-zin	"Partial skull."	Member of the Willow Wash local fauna.
Parasaurolophus	P. tubicen		De-na-zin	"Disarticulated, associated skull and postcraniua, pertaining to at least [three] individuals."	Member of the Willow Wash local fauna.
Pentaceratops	P. fenestratus
Pentaceratops	P. sternbergi		De-na-zin Hunter Wash	More common in the lower part of the formation.	Member of the Willow Wash local fauna.
Sphaerotholus	S. goodwini		De-na-zin		Member of the Willow Wash local fauna.
Stegoceras	S. novomexicanum		Hunter Wash	"SMP VP-2790, incomplete parietal"	Also found in the upper Fruitland Formation.
Terminocavus	T. sealeyi		Hunter Wash
Navajoceratops	N. sullivani		Hunter Wash
Titanoceratops	T. ouranos		Hunter Wash		Member of the Willow Wash local fauna. Found to be a synonym of Pentaceratops sternbergii.
Ziapelta	Z. sanjuanensis		Hunter Wash De-na-zin	Complete skull lacking the lower jaws, first two cervical half rings.

Pterosaurs

Pterosaurs of the Kirtland Formation
Genus	Species	Location	Member	Abundance	Notes
Navajodactylus	N. boerei	Partial phalanx and ulna fragment	Hunter Wash Member

Saurischians

Saurischians of the Kirtland Formation
Genus	Species	Location	Member	Abundance	Notes	Images
Alamosaurus	A. sanjuanensis				Erroneously identified as a member of the Willow Wash fauna, specimens actually from the Naashoibito member of the Ojo Alamo Formation	Bistahieversor sealeyi Ornithomimus Saurornitholestes sullivani
Aublysodon	A. mirandus				Remains once attributed to the dubious tooth genus Aublysodon (and later Daspletosaurus) are now referred to Bistahieversor, although these remains (OMNH 10131) may possibly have come from the Fruitland Formation.
Bistahieversor	B. sealeyi		Farmington Hunter Wash
Daspletosaurus	Unnamed		De-na-zin Farmington Hunter Wash		Remains formerly referred to an unidentified or undescribed species of Daspletosaurus were originally attributed to the dubious tooth genus Aublysodon. These remains were later reclassified as belonging to the new genus Bistahieversor. Some of these remains (OMNH 10131), however, may have originated in the Fruitland Formation.
Ornithomimus	O. sp.		De-na-zin		Member of the Willow Wash local fauna.
Saurornitholestes	S. sullivani		De-na-zin
"Saurornitholestes"	"S." robustus		De-na-zin		Member of the Willow Wash local fauna. Originally assigned to Saurornitholestes, actually a troodontid.
Troodontidae	Indeterminate
Tyrannosauridae	Indeterminate

Turtles

Turtles of the Kirtland Formation
Genus	Species	Location	Member	Abundance	Notes
Basilemys	B. nobilis		De-na-zin		Member of the Willow Wash local fauna.
Denazinemys	D. nodosa		De-na-zin		Member of the Willow Wash local fauna.
Neurankylus	N. baueri		De-na-zin		Member of the Willow Wash local fauna.
Plastomenus	P. robustus		De-na-zin		Member of the Willow Wash local fauna.
Thescelus	T. hemispherica		De-na-zin		Member of the Willow Wash local fauna.