Basin & Range: Deformation, Erosion & Sedimentation

33s Novice

How do the valleys form in a basin-range province?

As extension and uplift occur, erosion and sedimentation happen simultaneously but at slower rates. As extension slows down, erosion and sedimentation can overcome mountain building. A typical rift features inlude down-dropped faults and uplifted escarpments. The valleys become filled with erosional sediment.

Keypoints:

Typical rift features include

  • Down-dropped faults (valleys)
  • Uplifted escarpments (mountains)
  • Lakes form on floor of sediment-filled valleys

Related Animations

Over most of the last 30 million years, movement of hot mantle beneath the region caused the surface to dome up and then partially collapse under its own weight, as it pulled apart. Currently, there is very little actual stretching going on, and the small amount is concentrated on the Western and Eastern edges of the Basin and Range.

Animation Novice

During Basin & Range extension, the plates pull apart, the mantle rises and melts due to lower pressures near the surface. The style of eruption depends on how long the magma sits in the crust and undergoes processes such as crystallization and melting and assimilation of wall rock.

Animation Novice

Cross section of the shallow crust in the Basin & Range. Earthquake produces seismic waves that bump an array of seismic stations. One station records the arrival of the seismic waves on a seismogram. 

Animation Novice

Stratigraphy is the branch of geology that studies rock layers; structure includes the faults and folds that result from regional & local forces acting on the area. A hypothetical cross section is studied by going back to the beginning to study its progressive geologic history.

Animation Novice

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