Notes 11 – Erosion: GRAVITY AND WIND Mrs. Gordon Earth Science Tuesday, September 11, 2018

1. Erosion and Gravity Recall: Weathering, erosion and deposition act together in a cycle that wears down and builds up Earth’s surface. Erosion – the process by which natural forces move weathered rock and soil from one place to another. Deposition – a process that occurs when sediments are laid down after being eroded. ~ The force of GRAVITY = MASS MOVEMENT of Earth materials.

A. Landslide - rock and soil quickly slides down a slope Oso Landslide 2014 info B. Avalanche /mudslide – SNOW or MUD quickly slides down a slope

C. Slump – one large mass of soil suddenly slips down a slope D. Creep – very SLOW downhill mass movement

2. Erosion and Wind A. Fine grains – suspended in the air B. Medium grains – skip or bounce along (saltation) C. Coarse grains – slide or roll on the ground

3. Deposition and Wind A. Sand dune – a large deposit of windblown sand B. Loess – wind blown SILT deposits

Example = The Palouse region in Northern Idaho is made of loess blown in from Oregon and Washington. Mostly volcanic materials/ash, deposits are up to 30 ft. thick. The soil is very fertile and holds moisture well, no irrigation is required. Crops include winter wheat, barley, peas and lentils.

Mysterious Moving Rocks Clip Mystery Solved!?!