Kirtland Formation

Not to be confused with the Kirkland Formation, a Silurian geologic formation in New York, US.

The Kirtland Formation (originally the Kirtland Shale) is a sedimentary geological formation.^[1]

Kirtland Formation
Stratigraphic range: Campanian (typically Kirtlandian) 75–73.5 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Kirtland Formation at its type location south of Kirtland, New Mexico
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	36.708°N 108.350°W / 36.708; -108.350
Approximate paleocoordinates	42.6°N 76.3°W / 42.6; -76.3
Region	New Mexico
Country	United States
Extent	San Juan Basin
Type section
Named for	Kirtland Post Office
Named by	C.M. Bauer
Year defined	1916
Kirtland Formation (the United States) Show map of the United States Kirtland Formation (New Mexico) Show map of New Mexico

Kirtland Formation outcrops near Coal Creek

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.^[2] 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 73.83 ± 0.18 Ma ago. The top of the De-na-zin member, which contains the Willow Wash local fauna, has been dated to 73.49 ± 0.25 Ma ago.^[1]

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.^[1]

History of investigation

The formation was named by C.M. Bauer in 1916 for exposures near the Kirtland Post Office.^[3]

Stratigraphy

Main article: San Juan Basin § Stratigraphy

Upper Cretaceous stratigraphy of the San Juan Basin

Vertebrate paleofauna

Saurischians

Saurischians of the Kirtland Formation
Genus	Species	Member	Material	Notes	Images
Alamosaurus[4]	A. sanjuanensis[4]			Specimens actually from the Naashoibito member of the Ojo Alamo Formation[5]	Alamosaurus Bistahieversor Saurornitholestes Struthiomimus
Aublysodon[6]	A. mirandus[6]	Hunter Wash[6]		Remains are now referred to Bistahieversor, although these remains may possibly have come from the Fruitland Formation.[7]
Bistahieversor[8]	B. sealeyi[8]	Hunter Wash[8]	An articulated skull and undescribed postcranial skeleton of an adult individual, and an incomplete skull and postcranial skeleton of a juvenile individual.[8]	A eutyrannosaur tyrannosauroid also known from the Fruitland Formation.[8]
Caenagnathidae[9]	Indeterminate[9]	De-na-zin[9]	A nearly complete right tibia[9]	Indeterminate caenagnathid remains.[9]
Daspletosaurus[6]	Indeterminate[6]	Hunter Wash[8]		Remains are now referred to Bistahieversor, although these remains may possibly have come from the Fruitland Formation.[7]
Dromaeosauridae[10]	Indeterminate[10]		Numerous isolated teeth.[10]	Indeterminate dromaeosaurid remains.[10]
Ornithomimidae[10]	Indeterminate[10]	De-na-zin[10]	A distal end of a phalanx, and [two] partial manual unguals.[10]	Indeterminate ornithomimid remains.[10]
Saurornitholestes[11]	S. sullivani[11]	De-na-zin[11]	A nearly complete frontal.[11]	A saurornitholestine dromaeosaurid, sister taxa to Saurornitholestes langstoni.[11]
"Saurornitholestes"	"S." robustus[12]	De-na-zin[12]	A nearly complete frontal.[12]	Originally assigned to Saurornitholestes, actually a troodontid.[13]
cf. Struthiomimus[10]	cf. S. altus[10]		A centrum of a dorsal vertebra, distal portion of a metatarsal, and proximal phalanx.[10]	Indeterminate remains that may belong to Struthiomimus altus.[10]
Tyrannosauridae[10]	Indeterminate[10]		A partial skeleton, dentary, metatarsal, and numerous teeth.[10]	Indeterminate tyrannosaurid material.[10]

Ornithischians

Ornithischians reported from the Kirtland Formation
Genus	Species	Member	Material	Notes	Images
Ahshislepelta[14]	A. minor[14]	Hunter Wash[14]	A partial girdle, scapulocoracoids, humerus, proximal portion of the radius, cervical and/or dorsal vertebrae, complete and fragmentary thoracic osteoderms, and other unidentifiable postcranial fragments.[14]	An ankylosaurine ankylosaurid part of the Hunter Wash Member.[14]	Bisticeratops Kritosaurus Naashoibitosaurus Nodocephalosaurus (right) Pentaceratops Sphaerotholus Stegoceras Terminocavus Navajoceratops Titanoceratops Ziapelta
Anasazisaurus[15]	A. horneri[15]	De-Na-Zin[15]	An incomplete skull consisting of premaxillae, nasals, maxilla, lacrimal, jugal, prefrontal, postorbital, squamosal, frontal, parietal, and fragment of dentary with teeth.[15]	A kritosaurin hadrosaurid from the De-Na-Zin Member.[15]
Bisticeratops[16]	B. froeseorum[16]	Farmington[16]	A nearly complete skull.[16]	A chasmosaurine ceratopsid, originally identified as a specimen of Pentaceratops.[16]
Kritosaurus[15]	K. navajovius[15]	De-na-zin[15]	[Two] incomplete skulls, an atlas, axis and cervical vertebrae.[15]	A kritosaurin hadrosaurid also known from the Cerro del Pueblo Formation of Mexico.[15]
Naashoibitosaurus[15]	N.ostromi[15]	De-na-zin[15]	A skull lacking the premaxillae and mandible, a partial humerus, cervical vertebrae and dorsal vertebrae.[15]	A kritosaurin hadrosaurid, distinct from Kritosaurus.[15]
Nodocephalosaurus[17]	N. kirtlandensis[17]	De-na-zin[17]	A partial skull.[17]	An ankylosaurine ankylosaurid that has cranial ornamentation similar to Akainacephalus, an ankylosaur from the Kaiparowits Formation.[17][18]
Parasaurolophus[19]	P. tubicen[19]	De-na-zin[19]	[Two] incomplete and fragmentary skulls.[19]	A lambeosaurine hadrosaurid known from partial cranial remains.[19]
Pentaceratops[20]	P. fenestratus[20]	De-na-zin Member[21]	A crushed but nearly complete skull, mandible, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, chevrons, scapulae, coracoids, radii, ulnae, ischia, ilia, pubes, femora, tibiae, astragali, manual phalanxes and manual unguals.[21]	A junior synonym of Pentaceratops sternbergii, diagnostic characteristics of the species were pathologies.
	P. sternbergi[20]	De-na-zin[22]	A crushed but nearly complete skull, mandible, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, chevrons, scapulae, coracoids, radii, ulnae, ischia, ilia, pubes, femora, tibiae, astragali, manual phalanxes and manual unguals.[21]	A chasmosaurine ceratopsid also known from the Fruitland Formation.[21]
Sphaerotholus[23]	S. goodwini[23]	De-na-zin[23]	A partial skull lacking the facial and palatal elements.[23]	A pachycephalosaurine pachycephalosaurid also known from the Hell Creek and Horseshoe Canyon Formation.[23]
Stegoceras[24]	S. novomexicanum[24]	Hunter Wash[24]	An incomplete parietal.[24]	A basal pachycephalosaurid also known from the upper Fruitland Formation.[24]
Terminocavus[25]	T. sealeyi[25]	Hunter Wash[25]	A parietal, partial squamosal, jugal, epijugal, partial quadratojugal, partial sacrum and vertebral fragments.[25]	A chasmosaurine ceratopsid that has been hypothesized to form an anagenetic series with several other chasmosaur species, including Navajoceratops.[25]
Navajoceratops[25]	N. sullivani[25]	Hunter Wash	A parietal, squamosal fragments, fused jugal\epijugal and other unidentified cranial fragments.[25]	A chasmosaurine ceratopsid that has been hypothesized to form an anagenetic series with several other chasmosaur species, including Terminocavus.[25]
Titanoceratops[26]	T. ouranos[26]		A partial skull, syncervical vertebrae, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, ribs, humeri, radius, femora, tibiae, fibula, ilia, ischia, and ossified tendons.[26]	Possibly represents a junior synonym of Pentaceratops, holotype may possibly have come from the Fruitland Formation.[26]
Ziapelta[27]	Z. sanjuanensis	Hunter Wash [27] De-na-zin [27]	A complete skull, [two] first cervical half-rings, fragmentary second cervical half ring, and numerous fragmentary osteoderms.[27]	An ankylosaurine ankylosaurid closely related to Scolosaurus.

Pterosaurs

Pterosaurs of the Kirtland Formation
Genus	Species	Location	Member	Abundance	Notes	Images
Navajodactylus[28]	N. boerei[28]		Hunter Wash Member[28]	Partial phalanx and ulna fragment[28]	A possible azhdarchid pterosaur known from fragmentary remains.[28]

Crurotarsans

Crurotarsans of the Kirtland Formation[21]
Genus	Species	Location	Member	Abundance	Notes	Images
Brachychampsa	B. montana		De-na-zin		Member of the Willow Wash local fauna.
Denazinosuchus	D. kirtlandicus		De-na-zin		Member of the Willow Wash local fauna.
Leidyosuchus[29]	Indeterminate[29]		De-na-zin		Member of the Willow Wash local fauna.

Turtles

Turtles of the Kirtland Formation[21]
Genus	Species	Location	Member	Abundance	Notes	Images
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.

Bony fish

Bony fishes of the Kirtland Formation[21]
Genus	Species	Location	Member	Abundance	Notes
Melvius	M. chauliodous		De-na-zin		Member of the Willow Wash local fauna.

Cartilaginous fish

Cartilaginous fish of the Kirtland Formation[21]
Genus	Species	Location	Member	Abundance	Notes
Myledaphus	M. bipartitus		De-na-zin		Member of the Willow Wash local fauna.

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

See also

• List of stratigraphic units with dinosaur body fossils