Coalmont Formation facts for kids

Quick facts for kids Coalmont Formation Stratigraphic range: Paleocene-Wasatchian ~60–50Ma PreЄ Є O S D C P T J K Pg N
Coalmont Formation, Jackson County, Colorado
Type	Formation
Underlies	North Park Formation
Overlies	Cretaceous strata
Thickness	9,000 feet (2,700 m)
Lithology
Primary	Sandstone
Other	Clay, Shale, Coal
Location
Coordinates	40°24′N 106°30′W / 40.4°N 106.5°W / 40.4; -106.5
Approximate paleocoordinates	45°00′N 90°18′W / 45.0°N 90.3°W / 45.0; -90.3
Region	Colorado
Country	United States
Extent	North Park intermountaine basin
Type section
Named for	Coalmont, Jackson County, Colorado
Named by	A. L. Beekly

The Coalmont Formation is a special type of rock layer found in the North Park basin in Colorado. It's like a giant history book made of stone. This formation holds amazing clues about Earth's past.

Scientists have found many fossils of ancient plants and layers of coal here. These finds tell us about a time called the Paleogene period. This period was about 60 to 50 million years ago.

Discovering Ancient Life in Coalmont

Geologic map of the North Park Basin with the Coalmont Formation indicated in light green (Tmc)

The Coalmont Formation is famous for its fossils. These fossils help us understand what life was like millions of years ago. Imagine finding plants and insects that lived when dinosaurs were just gone!

Fossil Insects

Scientists have found several types of ancient insects in the Coalmont Formation. These tiny fossils give us a peek into the insect world of the past. They include:

• Calandrites hindsi
• ?Calandrites ursorum
• ?Carabites arapahoensis
• Curculio beeklyi
• Ophryastites hendersoni

Fossil Plants (Flora)

The Coalmont Formation is especially rich in plant fossils. These fossils show us the kinds of forests and plants that grew here long ago. Many of these plants are related to trees and shrubs we see today. Some of the plant fossils found are:

• Allantodiopsis erosa
• Ampelopsis acerifolia
• Betula stevensoni
• Carya antiquorum
• Cercidiphyllum arcticum
• Cissus marginata
• Eucommia serrata
• Fraxinus eocenica
• Glyptostrobus nordenskioldi
• Hydromystria expansa
• Lastrea goldiana
• Laurophyllum perseanum
• Laurus socialis
• Lygodium coloradense
• Metasequoia occidentalis
• Mimosites coloradensis
• Nordenskioldia borealis
• Persea brossiana
• Platanus nobilis
• P. raynoldsi
• Prunus corrugis
• Pterocarya hispida
• Quercus greenlandica
• Q. sullyi
• ?Robinia wardi
• Sassafras thermale
• Sparganium antiquum

Connecting with Other Ancient Sites

The Coalmont Formation is part of a larger geological time period called the Wasatchian age. This age is important for understanding how life changed across North America. Scientists compare fossils from the Coalmont Formation with those found in other rock layers from the same time. This helps them learn about ancient environments and how animals and plants spread.

For example, fossils like Coryphodon (an ancient mammal) and Paramys (an early rodent) have been found in the Coalmont Formation. They are also found in other formations like the Wasatch Formation and Willwood Formation. This shows that similar animals lived in different parts of North America during the Wasatchian age.

The table below shows some of the animals and plants found in the Coalmont Formation and other places during the Wasatchian age. It also shows if the area had volcanic activity or was a river, lake, or ocean environment.

Wasatchian correlations in North America

Formation	Wasatch	DeBeque	Claron	Indian Meadows	Pass Peak	Tatman	Willwood	Golden Valley	Coldwater	Allenby	Kamloops	Ootsa Lake	Margaret	Nanjemoy	Hatchetigbee	Tetas de Cabra	Hannold Hill	Coalmont	Cuchara	Galisteo	San Jose	Ypresian (IUCS) • Itaboraian (SALMA) Bumbanian (ALMA) • Mangaorapan (NZ)
Basin	Powder River Uinta Piceance Colorado Plateau Wind River Green River Bighorn	Piceance	Colorado Plateau	Wind River	Green River	Bighorn		Williston	Okanagan	Princeton	Buck Creek	Nechako	Sverdrup	Potomac	GoM	Laguna Salada	Rio Grande	North Park	Raton	Galisteo	San Juan
Country	United States								Canada					United States		Mexico	United States
Copelemur
Coryphodon
Diacodexis
Homogalax
Oxyaena
Paramys
Primates
Birds
Reptiles
Fish
Insects
Flora
Environments	Alluvial-fluvio-lacustrine	Fluvial				Fluvial	Fluvio-lacustrine	Fluvial	Lacustrine		Fluvio-lacustrine		Deltaic-paludal	Shallow marine		Fluvial	Shallow marine	Fluvial		Fluvial		Wasatchian volcanoclastics Wasatchian fauna Wasatchian flora
Volcanic	Yes	No							Yes	No	Yes	No	Yes	No						Yes	No