Franklin Mountains (Texas)
The Franklin Mountains of Texas are a small range (23 miles long, 3 miles (4.8 km) wide) that extend from El Paso, Texas north into New Mexico. 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.
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
|Peak||North Franklin Peak|
|Elevation||7,192 ft (2,192 m)|
|States||Texas and New Mexico|
|Age of rock||Cretaceous|
|Type of rock||Sedimentary, Igneous|
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, the oldest in Texas.
- Van Hise, C.R. and Leith, C.K. 1909. Pre-Cambrian Geology of North America. United States Geological Survey, Bulletin 360, 939 pp. (See pp. 746-748)
- http://www.tpwd.state.tx.us/publications/pwdpubs/media/pwd_br_p4501_0124g.pdf Precambrian rocks can be seen in the Tom Mays unit of the Franklin Mountains park
- Brooks, A.H. 1904. The Geological Society of Washington. Science NS 19(490):794-796.
- Richardson, G.B. 1909. El Paso folio, Texas. United States Geological Survey, Folios of the Geologic Atlas, No. 166, 11 pp. (See Figure 10)
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