Franklin Mountains (Texas)

Franklin Mountains
Aerial view of the Franklin Mountains from the south, with El Paso's Scenic Drive at the bottom, and New Mexico's Organ Mountains on the horizon in the distance
Highest point
PeakNorth Franklin Peak
Elevation7,192 ft (2,192 m)
Coordinates31°54′10″N 106°29′36″W / 31.90278°N 106.49333°W / 31.90278; -106.49333
Geography
Map
CountryUnited States
States
  • Texas
  • New Mexico
Geology
OrogenyLaramide orogeny
Rock ageCretaceous
Rock type(s)Sedimentary, Igneous

The Franklin Mountains of Texas (Spanish: Sierras de los Mansos[1]) are a small range 23 miles (37 km) long, 3 miles (5 km) wide that extend from El Paso, Texas, north into New Mexico.[2] The Franklins were formed due to crustal extension related to the Cenozoic Rio Grande rift. Although the present topography of the range and adjoining basins is controlled by extension during rifting in the last 10 million years, faults within the range also record deformation during the Laramide orogeny, between 85 and 45 million years ago.

The highest peak is North Franklin Peak at 7,192 feet (2,192 m). Much of the range is part of the Franklin Mountains State Park. The mountains are composed primarily of sedimentary rock with some igneous intrusions. Geologists refer to them as tilted-block fault mountains and in them can be found 1.25 billion-year-old Precambrian rocks,[3] the oldest in Texas.[2][4]

  1. ^ Miles, Robert W. (June 12, 2010). "Franklin Mountains". tshaonline.org. Retrieved March 29, 2020.
  2. ^ a b Van Hise, C. R.; Leith, C. K. (1909). Pre-Cambrian Geology of North America. United States Geological Survey, Bulletin. Vol. 360. pp. 746–748. doi:10.3133/b360. OCLC 271845.
  3. ^ "Franklin Mountains State Park : Interpretive Guide" (PDF). Texas State Parks. 2019. Precambrian rocks can be seen in the Tom Mays unit of the Franklin Mountains park.
  4. ^ Brooks, A. H. (1904). "The Geological Society of Washington". Science. NS. 19 (490): 794–796. doi:10.1126/science.19.490.794.