TODAY

• Get out your ESRT and a piece of paper

• The following questions are from your ESRT.

• You’ll have a minute per question…

Question 1

• What are 2 examples of weathering?

Question 2

• What is the difference between soil and dirt?

Question 3

• What is the P-wave travel time for 4000 km?

Question 4

• What layer of the earth has a greater temperature than melting point?

Answers

• Two examples– Abrasion, Frost action

• Soil and Dirt?– Darker, particle size

• P-wave travel time for 4000 km? – 00:07:00

• What layer of the earth has a greater temperature than melting point?– Outer Core

Erosion

Movement of weathered particles

Vocab

• Agents of erosion

• Suspension

• Saltation

• Creep

• Angle of repose

• Mass wasting

Weathering Vs Erosion

• Weathering– Breaking down of

rocks and other particles into smaller pieces

• Erosion– Transport of the

weathered particles.

TALUS ?

Agents of Erosion1) Gravity

2) Water

3) Wind

4) Ice

Water

• Water when driven by gravity can be very powerful.

• Think of the drainage ditch after it rains – does the water flow fast? Is it clean?

Wind• 3 things to know.

1. Suspension – Stuff in the air

2. Saltation – Bouncing

3. Creep – Rolling on the groundDust bowl, Causes???

Ice

• Glaciers move ice down a slope picking up sediments along the way.

• Long Island is simply glacial Poop!

Gravity• Gravity drives all erosion, but one form

more important to know is mass movements.

• This is when the soil fails and falls or slides down a slope.

• Angle Of Repose– Angle where material

stays on surface!

Mass movements • Slump

– This is when the land slides down equally.

• Slide– This is when the land

slides down not equally.

• Fall- avalanche– The land falls

• Flow– The land is liquefied

and flows down.

Things that will increase mass movements

1. Change water content

2. Change slope

3. Change mass

4. Change vegetation

5. Change human activity

Tully Landslide ‘91

http://pubs.usgs.gov/of/1994/ofr-94-0615/tvstudy.htm

¼ mile

Tully Landslide

• April 30, 1993. After a long winter full of rain and snow. The saturated land gave away and began to flow down the hill.

Deposition

What is this?

What controls this?

Deposition

• This is like going to the bank geologically.

• Weathering breaks the rocks up

• Erosion moves the particles.

• Deposition leaves the particles on the ground.

Factors

• Particle Size– How big the sediments are.

• Shape– Round or flat

• Density– Weight and composition

• Settling rates– How fast things settle

Sorting Vs Unsorted

• ESRT page

• How to find

sediment size.

• How to find

Speed.

Ways to deposit

• Glaciers– Sorted or Unsorted

• Streams (Water)– Sorted or Unsorted

• Wind– Sorted or Unsorted

• Mass movements (gravity)– Sorted or Unsorted

Gravity

• Gravity alone does not sort sediment

• Landslides are the main form of gravity deposition.

• Why are sediments

unsorted?

Glaciers

• Glaciers leave sediment unsorted.

• Like gravity

Land slides

• What moves the

glacier?

Water• Streams, Rivers deposit sediment in

sorted layers.

• Why are sediments

sorted?

Wind

• Wind like water sorts sediments.

• Why are sediments sorted?

Wind

• Wind like water sorts sediments.

• Why are sediments sorted?