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Kirtland Formation
Stratigraphic range: Campanian (typically Kirtlandian)
75–73Ma
Kirtland Formation Outcrops Near Coal Creek by Nick Longrich.jpg
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; -108.350Coordinates: 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

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

San Juan Basin Upper Cretaceous stratigraphy PeerJ e5435 fig 1
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 NT small
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 BW
Kritosaurus navajovius
Sphaerotholus
Sphaerotholus goodwini
Terminocavus
Terminocavus sealeyi
Titanoceratops dinosaur
Titanoceratops ouranos
Ziapelta
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

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

Bihastieversor NT
Bistahieversor sealeyi
Saurornitholestes digging Burrows wahweap
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.

Bony fish

Bony fishes of the Kirtland Formation
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
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.
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