GEL 25 Lecture Notes - Lecture 7: Paunsaugunt Plateau, Navajo Sandstone, Headward Erosion
Document Summary
Coastline ran through central nevada into idaho. Navajo sandstone was a coastal desert near sea level. Uplift of colorado plateau happened much later. Early zion formed as the kayenta is eroded by the virgin river during floods. More recently, zion"s rockfalls create stiff vertical cliffs. Infiltration of water through the navajo sandstone along vertical fractures (joints) dissolves natural cement holding sand grains together, weakening the rock. Landscapes of national parks of the colorado plateau are erosional in origin - deep canyons, steep vertical cliffs, broad escarpments. Scenery formed by erosion of sedimentary layers along the edge of a plateau. Hoodoos: ornate pillars formed by weathering and erosion of bedded sedimentary rock. Pink cliffs of bryce canyon np exposed along the eastern edge of. 1000ft thick stack of shale, sandstone, limestone, and volcanic ash bed all deposited in a large inland lake. Freshwater fossils prove the area was previously a lake.
