Chapter 16

Landscape Evolution:

Topography is a Balance Between and Tectonic Uplift

1 is a Balance Between Erosion and Tectonic Uplift

2 Relief

• The relief in an area is the maximum difference between the highest and lowest elevation. – We have about 7000 feet of relief between Boulder and the Continental divide.


3 and Valleys

• A is a large mass of that projects above surrounding . • A is a continuous area of high elevation and high relief. • A is an area of low relief typically formed by and drained by a single stream. • A basin is a large low-lying area of low relief. In arid areas basins commonly have closed topography (no outlet to the ).

Mountains • Typically occur in ranges. • Glaciated forms –Horn –Arête • Mountains – Vertical Cliffs – Alluvial Fans

4 Mountain : Horn

Deserts: Vertical Cliffs and Alluvial Fans

5 Valleys and Basins • River Valleys – U-shape (Glacial) – V-shape (Active Water erosion) – -floored (depositional flood ) • Tectonic (Fault) Valleys (Basins) – Tectonic origin – San Luis Valley – Jackson Hole – Great Basin

U-shaped Valley: Glacial Erosion

6 V-shaped Valley: Active water erosion

Flat-floored Valley: Depositional Flood Plain

7 Desert and Semi-arid Landforms • A is a broad area of uplift with relatively little internal relief. • A is a small (<10 km2)plateau bounded by cliffs, commonly in an area of flat-lying sedimentary rocks. • A is a small (<1000m2) hill bounded by cliffs

Plateau, Mesa, Butte

8 National Monument


9 Desert and Semi-arid Landforms • A is an asymmetric in dipping sedimentary rocks as the Flatirons. • A hogback is ridge formed by near- vertical, resistant . (Dakota Ridge) • are areas of deeply gullied topography unsuitable for agriculture.


10 Hogback


11 Terms

• Relief • U-shaped • Mountain Valley • Mountain • V-shaped Range Valley • Valley • Plateau • Basin • Mesa • Horn • Butte • Arête • Cuesta • • Hogback • Badlands