The Rio Grande Rift is a major component of the Sourthern Rocky mountain region. that extends from the center of Colorado, U.S.A., all the way down into Chihuahua, Mexico (Chapin, 1994) (figure 1). The area has long been used by humans as a north south trade route and also goes by the name “El Camino Real de Tierra Adentro” (“The Royal Road of the Interior Land”). The understanding of this rift zone is also an area of importance because it contains valuable resources such as hydrocarbons, mineral deposits and groundwater, as well as human hazards, such as earthquakes (Baldridge, 1989). For us to understand geological formation of the rift we must look at the history of the tectonic activity of the Rocky Mountains.
Background
Leading up to the origin of the Rio Grande rift started during the Cretaceous period, approximately 140 million years ago …show more content…
The first phase phase of rifting lasted approximately 10-12 million years , and was caused by the slowing subducting Farallon plate. This formed low angle faults and grabens. These geologic features can be found throughout the southern part of the Rio Grande rift. The second rifting phase occurred approximately 20 million years ago, and was triggered by the disappearance of the Farallon plate in the subduction zone (Baldridge, 1989). During this time frame the Farallon plate had completely subducted into the North American plate and the part of the Pacific plate started touching North American plate in a lateral shear motion. Baldridge hypothesized that the second major extension of the Rio Grande rift might have been caused by the gaps between the two plates as well as the lateral shear motion of the Pacific and North America (figure). This second extension gave way to the opening of basins and sinking of large blocks of land, which can be found all throughout the Northern and Central areas of the Rio Grande
Background
Leading up to the origin of the Rio Grande rift started during the Cretaceous period, approximately 140 million years ago …show more content…
The first phase phase of rifting lasted approximately 10-12 million years , and was caused by the slowing subducting Farallon plate. This formed low angle faults and grabens. These geologic features can be found throughout the southern part of the Rio Grande rift. The second rifting phase occurred approximately 20 million years ago, and was triggered by the disappearance of the Farallon plate in the subduction zone (Baldridge, 1989). During this time frame the Farallon plate had completely subducted into the North American plate and the part of the Pacific plate started touching North American plate in a lateral shear motion. Baldridge hypothesized that the second major extension of the Rio Grande rift might have been caused by the gaps between the two plates as well as the lateral shear motion of the Pacific and North America (figure). This second extension gave way to the opening of basins and sinking of large blocks of land, which can be found all throughout the Northern and Central areas of the Rio Grande