The Vermejo Formation is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cret ...

age. It

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets. Features Outcrops do not cover the majority of the Earth's land surface because in most p ...

s in the

Raton Basin The Raton Basin is a geologic structural basin in southern Colorado and northern New Mexico. It takes its name from Raton Pass and the town of Raton, New Mexico. In extent, the basin is approximately east-west, and north-south, in Huerfano an ...

of northeastern

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

and southern

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

Description

The formation consists of a light gray, soft,

friable In materials science, friability ( ), the condition of being friable, describes the tendency of a solid substance to break into smaller pieces under stress or contact, especially by rubbing. The opposite of friable is indurate. Substances tha ...

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

and

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

, which is

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

aceous in part, and may have

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

seams or thin coal beds. The Vermejo Formation is about 375 feet (116m) thick at the type locality which is Vermejo Park in

Colfax County, New Mexico Colfax County is a county in the U.S. state of New Mexico. As of the 2020 census, the population was 12,387. Its county seat is Raton. It is south from the Colorado state line. This county was named for Schuyler Colfax (18231885), seventee ...

. The Vermejo Formation unconformably overlies the Trinidad Sandstone, and unconformably underlies the Raton Formation. The Rail Canyon sandstone member is a sandstone bed up to thick that is found above the base of the formation.

Economic geology

The Vermejo Formation is an historically important coal-bearing formation. Mining began in 1870 in the rich Raton coal bed near the base of the Vermejo Formation. The bed contained

bituminous coal Bituminous coal, or black coal, is a type of coal containing a tar-like substance called bitumen or asphalt. Its coloration can be black or sometimes dark brown; often there are well-defined bands of bright and dull material within the coal seam, ...

s of

coking Coking is the process of heating coal in the absence of oxygen to a temperature above to drive off the volatile components of the raw coal, leaving behind a hard, strong, porous material with a high carbon content called coke. Coke is predomina ...

quality. These were being extensively exploited by 1924 but the beds were largely exhausted by 1965. The formation has also been exploited for

coalbed methane ''Coalbed methane'' (CBM or coal-bed methane), coalbed gas, or coal seam gas (CSG) is a form of natural gas extracted from coal beds. In recent decades it has become an important source of energy in United States, Canada, Australia, and other co ...

History of investigation

The Vermejo Formation was originally named by W. T. Lee in 1913 in the ''

American Journal of Science The ''American Journal of Science'' (''AJS'') is the United States of America's longest-running scientific journal, having been published continuously since its conception in 1818 by Professor Benjamin Silliman, who edited and financed it himself ...

''. In 1917, Lee described the formation more completely.

References

{{Chronostratigraphy of Colorado, Mesozoic state=expanded Cretaceous formations of New Mexico Geologic formations of Colorado Upper Cretaceous Series of North America Sandstone formations of the United States Shale formations of the United States Coal formations

Description

Economic geology

History of investigation

See also

References