Geologic Feature


The flat valley or other ground that is bounded on two sides by steep vertical walls. This almost creates a v-shaped gap in the landscape. Canyons are often formed by rivers and streams, which have cut through the rock of the earth and created a deep valley. A famous example of a canyon is the Grand Canyon in Arizona. This canyon was created by the Colorado River which, through preferential erosion, incised the canyon into the bedrock. Canyons are numerous in the southwestern United States due to the specific environment of the region and the erosion that has occurred there over millions of years.


A large piece of rock that has been detached from a larger rock surface by weathering, whether physical or chemical.


A seep, also known as a gravity spring, is an area where water slowly oozes from the ground and collects. A seep is created when the water table intersects with a fissure in the ground surface, causing the water to be pushed up through a fissure and collect on the surface.


In the context of landscapes and terrains, the term trough refers to an elongated, shallow groove between hills or raised rock formations.


Also known as an arroyo seco, gulch, or gully, a wash is a dry stream or river bed that does not hold water most of the time, but that is subject to seasonal flooding. Washes vary greatly in depth, width and length, and can be found all over the world in semiarid and desert areas. They are common throughout New Mexico and Southwestern parts of the U.S., where prolonged droughts keep them dry and heavy rains make them prone to flash flooding.

catch basin

A naturally-occurring or man-made reservoir that collects surface water. Catch basins vary in size and shape, depending on the terrain and how they are positioned within it.


One of the most abundant rock types underlying the Earth's surface, especially the upper oceanic crust, basalt is a dark-colored igneous rock. It can be fine-grained and compact, although as it usually reaches the earth's surface via volcanic activity and lava flows, hardening into rough, crystallized, pumiceous formations. Many areas within the U.S. Southwest are scattered with extinct volcanoes, and basalt is therefore abundant throughout the region.


Geologic faults form along the edges of tectonic plates, which are planar fractures in the earth’s crust, as the plates become compressed or filled with tension as they are forced together. When faults move, they can form valleys and mountains. In addition, as faults react to the forces that the huge tectonic plates exert against each other, fissures perpendicular to the earth's surface can extend deep below ground to reserves of molten rock, which, if they reach the surface, form volcanos. When the energy of plates under compression is released as the plates grind against each other, it can also cause earthquakes. There are many faults in the American Southwest, both active and inactive, including the Rio Grande Rift in New Mexico.

Sandia Mountains, New Mexico

This mountain range runs north to south and is located east of Albuquerque, New Mexico. The highest peak, Sandia Crest, is 10,678 feet in elevation. The range may have originally been called “San Diaz” or Saint Diaz. Another theory suggests that, because Sandia is Spanish for “watermelon,” Sandia could refer to the pink color the mountains reflect at sunset. The name for the mountain in Navajo is, “Dził Nááyisí” or “Mountain that Revolves,” perhaps referring to the large circular bowls that form the west-facing aspect of the range.

In 1865, in order to subdue the Navajo, the U.S. Army rounded up the Navajo and forcibly made them walk 450 miles from their homeland, centered near Canyon de Chelley in northwestern New Mexico, to the Fort Sumner/Bosque Redondo reservation in southeastern New Mexico. Known as “The Long Walk,” four primary routes comprised the forced march: two skirted the western edge of the Sandia Mountains and two cut through Tijeras canyon and across the Sandia Mountains. Therefore, this unfortunate part of Navajo history is tied to the mountain range.

Additionally, there is a Paleolithic site on the north end of the mountain range in Sandia Cave. This site includes stone tools from the ancient Sandia Culture, which were excavated in the 1930s and 1940s by Frank Hibben, an archaeology professor from the University of New Mexico in Albuquerque.


The layer of rock that tops some geological uplifts. Often seen in the form of a wall or cliff, rimrock forms a cap and sometimes even an overhang over the softer rock beneath, which, as it erodes, can create sculpturesque forms in the remaining geologic material, including caves.


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