Kirtland Formation facts for kids

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 is a special type of sedimentary rock layer. It was first called the Kirtland Shale. This rock formation is a record of ancient environments. It tells us about the land and life that existed millions of years ago.

What is the Kirtland Formation?

The Kirtland Formation is made of mud and sand. These materials were left behind by ancient rivers and floods. This happened on a flat coastal plain. This plain was next to an ancient inland sea. This sea covered parts of North America during the late Cretaceous Period.

The Kirtland Formation sits on top of another rock layer called the Fruitland Formation. You can find the Kirtland Formation in the San Juan Basin. This basin is in the states of New Mexico and Colorado in the United States.

How Old is the Kirtland Formation?

Scientists have studied the Kirtland Formation very carefully. They use special methods to find out its age. The bottom part of the Kirtland Formation is about 75 million years old. This part is called the Hunter Wash member.

The Kirtland Formation is divided into different layers, or "members."

• The Hunter Wash member is the oldest, about 75 million years old.
• Above it is the Farmington member, which is about 74 million years old.
• The De-na-zin member is on top of the Farmington member. It is about 73.37 million years old.
• The very top of the De-na-zin member is about 73.04 million years old.

There's also a layer called the Naashoibito member. This layer was once thought to be part of the Kirtland Formation. But now, scientists believe it belongs to the Ojo Alamo Formation, which is a rock layer found above the Kirtland Formation.

How the Kirtland Formation Was Discovered

The Kirtland Formation was first named in 1916. A scientist named C.M. Bauer gave it its name. He named it after the Kirtland Post Office. This was near where he found the rock layers.

Rock Layers of the San Juan Basin

Upper Cretaceous stratigraphy of the San Juan Basin

Stratigraphy is the study of rock layers. It helps us understand how different layers formed over time. The image shows how the Kirtland Formation fits with other rock layers in the San Juan Basin.

Amazing Animals from the Kirtland Formation

The Kirtland Formation is famous for its many fossils. These fossils tell us about the animals that lived there millions of years ago. Many of these animals were dinosaurs!

Ancient Crocodilians (Crurotarsans)

Crurotarsans were a group of reptiles that included ancient relatives of crocodiles.

Plant-Eating Dinosaurs (Ornithischians)

Ornithischians were a large group of plant-eating dinosaurs. Many different kinds have been found here.

Flying Reptiles (Pterosaurs)

Pterosaurs were flying reptiles that lived at the same time as dinosaurs.

Lizard-Hipped Dinosaurs (Saurischians)

Saurischians include both giant long-necked dinosaurs and meat-eating dinosaurs.

Ancient Turtles

Many types of ancient turtles have been found in the Kirtland Formation.

Bony Fish

Fossils of bony fish have also been found.

Cartilaginous Fish

These are fish like sharks and rays, whose skeletons are made of cartilage instead of bone.

Images for kids

• 

  Kirtland Formation outcrops near Coal Creek

• 

  Kritosaurus

• 

  Naashoibitosaurus

• 

  Nodocephalosaurus (right)

• 

  Pentaceratops

• 

  Sphaerotholus

• 

  Stegoceras

• 

  Terminocavus

• 

  Navajoceratops

• 

  Titanoceratops

• 

  Ziapelta

• 

  Alamosaurus

• 

  Bistahieversor

• 

  Saurornitholestes

• 

  Struthiomimus

See also

In Spanish: Formación Kirtland para niños