1. Topic 9 Deposition Regents Earth Science

2. deposition  Is the “dropping” of transported materials  Or the processes by which transported materials are left in new locations

3. Factors Affecting Deposition

5. Particle size  Larger particles settle more quickly than smaller particles (if they have the same shape and density)  Colloids remain suspended indefinitely Particle Size Settling Rate Particle Size Settling Time

6. Particle Shape  Particles of the same size and maximum diameter will settle out in this order: round, oval, flat  The more spherical the particle, the faster the settling rate.  As flatness increases, settling time increases.

7. Remember: A short time is a high rate!

8. Particle density  The denser the particle, the faster it will settle in particles that have the same size and shape.

9. The rate at which particles are deposited by a stream is least affected by  1. size and shape of the particles  2. velocity of the stream  3. the stream’s elevation above sea level  4. density of the particles

10. A mixture of sand, clay, pebbles, and silt, of uniform shape and density, is dropped from a boat into a calm lake. Which material most likely would reach the bottom of the lake first?  1. sand  2. pebbles  3. clay  4. silt

11. sorting  the separation of particles during deposition

12. In sediments of mixed sizes, shapes, and densities  Roundest, largest, and densest particles will be at the bottom of each layer.  Smallest, flattest, and least dense will be at the top of each layer.

14. Vertical sorting  Sorting from top to bottom throughout a layer

15. Graded bedding  Layers of sediment that are each vertically sorted  Usually occurs in shallow, quiet bodies of water or in the ocean  Degree of sorting is usually greater in the bottom layer than in the top layer

16. Process of forming graded beds

17. Graded bedding

18. Horizontal sorting  The sorting of sediments into layers in which the particles are sorted horizontally, ranging from largest to smallest in the direction of travel of the transporting agent

20. Horizontal sorting

22. delta  A deposit formed at the mouth of a river as it empties into a quiet body of water  Named for the Greek letter delta

24. Nile Delta

25. Mississippi Delta

26. Alluvial fan  A deposit of sediment formed where the velocity of a river slows as it flows out of the mountains onto the flatland  Also called a land delta

27. Sediments deposited by water are  well sorted (either vertically or horizontally)  rounded  smooth  may show graded bedding