The Carrizo Mountains (36°50' N, 109°7'W) is a small, mostly circular mountain range 15 to 20 km (9 to 12 miles) in diameter located on the

Colorado Plateau The Colorado Plateau, also known as the Colorado Plateau Province, is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. This province covers an area of ...

in northeastern

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

. The range is about southwest of the

Four Corners The Four Corners is a region of the Southwestern United States consisting of the southwestern corner of Colorado, southeastern corner of Utah, northeastern corner of Arizona, and northwestern corner of New Mexico. The Four Corners area ...

. The highest summit, Pastora Peak, is in elevation, whereas elevations on the surrounding plateau are near . The mountains are within the Navajo Nation.

Teec Nos Pos, Arizona Teec Nos Pos (Navajo: '')'' is a census-designated place (CDP) in Apache County, Arizona, United States. The population was 507 at the 2020 census. It is the western terminus of U.S. Route 64. Geography Teec Nos Pos is located at (36.923142, - ...

, the closest community, is adjacent at the northern foothills, on Teec Nos Pos Wash, from Pastora Peak, about 5-mi miles to the north from the mountain's perimeter; Teec Nos Pos had about 800 inhabitants in the 2000 census.

Geology

The Carrizo Mountains primarily consist of

igneous rock Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main The three types of rocks, rock types, the others being Sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rock ...

s that intruded

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

through

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

marine strata. The most common igneous rock type is

porphyritic Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning all ...

hornblende Hornblende is a complex inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common in igneous and metamorphic rocks ...

diorite Diorite ( ) is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock) that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-silic ...

. Intrusive forms include

laccolith A laccolith is a body of intrusive rock with a dome-shaped upper surface and a level base, fed by a conduit from below. A laccolith forms when magma (molten rock) rising through the Earth's crust begins to spread out horizontally, prying ap ...

stocks Stocks are feet restraining devices that were used as a form of corporal punishment and public humiliation. The use of stocks is seen as early as Ancient Greece, where they are described as being in use in Solon's law code. The law describing ...

, sills, and

dikes Dyke (UK) or dike (US) may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), a subvertical sheet-like intrusion of magma or sediment * Dike (mythology), ''Dikē'', the Greek goddess of moral justice * Dikes ...

Age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

s of the igneous rocks range from 70 to 74 million years. Similar igneous-cored ranges of the

, including the

Henry Mountains The Henry Mountains is a mountain range located in the southeastern portion of the U.S. state of Utah that runs in a generally north-south direction, extending over a distance of about . They were named by Almon Thompson in honor of Joseph Henry ...

Abajo Mountains The Abajo Mountains, sometimes referred to as the Blue Mountains, is a small mountain range west of Monticello, Utah, south of Canyonlands National Park and north of Blanding, Utah. The mountain range is located within the Manti–La Sal National ...

and

La Sal Range The La Sal Mountains or La Sal Range are a mountain range located in Grand and San Juan counties in the U.S. state of Utah, along the border with Colorado. The range rises above and southeast of Moab and north of the town of La Sal. This range i ...

, formed ca. 31 to 20 million years ago, making them distinctly younger than the late Cretaceous intrusions of the Carrizo Mountains. Radiometric ages of igneous intrusions in

Sleeping Ute Mountain Ute Mountain, also known as Ute Peak or Sleeping Ute Mountain (; Ute: ''Wisuv Káruv'', Navajo: ''Dził Naajiní''), is a peak within the Ute Mountains, a small mountain range in the southwestern corner of Colorado. It is on the northern edge o ...

are essentially identical to those of the diorite intrusions in the Carrizos. Both the Carrizo Mountains and Sleeping Ute Mountain are located along the southwest extension of the

Colorado Mineral Belt The Colorado Mineral Belt (CMB) is an area of ore deposits from the La Plata Mountains in Southwestern Colorado to near the middle of the state at Boulder, Colorado and from which over 25 million troy ounces (778 t) of gold were extracted begin ...

, a 250-mile long lineament characterized by igneous rocks associated with abundant ore deposits. Large ore deposits have not been found in the igneous rocks of the Carrizo Mountains, although small deposits of

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

vanadium Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer ( pas ...

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

and

silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...

have been found in the sedimentary rocks of the

Morrison Formation The Morrison Formation is a distinctive sequence of Late Jurassic, Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandsto ...

References

* * * {{Coord, 36, 50, N, 109, 07, W, source:enwiki-plaintext-parser, display=title Geography of the Navajo Nation Mountain ranges of Apache County, Arizona Mountain ranges of Arizona