1. Relative susceptibility To weathering

2. Products of Weathering

3. Factors influencing Weathering Rates
Rock structures – chemical/mineral composition, physical features
Topography
Climate
Vegetation
Time

5. Sediments and Sedimentary Rocks

6. Sediments - unconsolidated particles created by
1. The weathering of rock
2. The secretions of organisms or decomposition of organic matter
3. Chemical precipitation

7. Sedimentary Rock Formation
Weathering – breakdown both physically (clasts) or chemically
Erosion – loosening of weathered products (clasts) and initial transport
Transportation – movement of materials via wind, water, or ice; sorting and rounding can occur
Deposition – material settles out of the transporting medium
Lithification – process of either cementation or compaction of the material

8. W. W. Norton

9. Sedimentary Rocks Composed of lithified sediments
by compaction – weight of overlying sediment compresses sediment, important in fine-grained sediments
by cementation – materials carried in solution precipitates minerals - iron oxides, carbonates, silica
Two Classifications
- clastic
-nonclastic

10. Fig. 7.16
W. W. Norton

11. Sedimentary Rocks
Clastic Rock – composed of fragments of preexisting rocks.
Nonclastic Rock – composed of chemical precipitates or biochemical matter.

12. Daily Question
Use a Venn diagram to compare and contrast clastic, chemical nonclastic, and biochemical nonclastic sedimentary rocks. Identify at least five characteristics.
Clastic
Chemical
Biochemical

13. Types of Sediments - Clastic
Broken fragments of rock produced by weathering.
Classified according to size.
Range in size from largest boulder to smallest clay particle.

14. Clastic Texture
Increasing distance from source
The size, shape, and distribution of particles that collectively make up a rock
Increasing distance from source

15. Which sample is closer to the source of sediment?

16. Sorting - a function of transport mechanism
1. Water
2. Wind
3. Glaciers

17. Sorting by Wind

18. Fig. 7.26a
Stephen Marshak

19. Graded Beds
Fining up

20. Texture and Transport Distance
In general, as transport distance increases, rounding and sorting increase.
Examples:
Breccia – cemented close to source
Conglomerate – transported then cemented

21. Types of Sediments - Biogenic
Terrestrial sediments - mainly plant matter ex. Coal
Marine sediments - mainly carbonates
Corals - large components of reefs.
Bivalves, gastropods, foraminifers - whole or partial skeletons form sand and gravels.
Algae, crinoids, echinoderms, bryozoans - disintegrate to form some sand particles and lime mud.
Diatoms, Radiolaria – bedded chert sio2

22. Coral (carbonate)

23. Foramanifera

24. Diatoms

25. Types of Sediments - Chemical
Inorganic process, no biological activity involved.
Formed by minerals precipitating from solution. i.e. –
Ca2+ + CO32- = CaCO3
Na+ + Cl- = NaCl

26. Chemical Sediments Terrestrial - Evaporites: Gypsum - CaSO4 . H2O
Anhydrite -CaSO4
Halite - NaCl

28. Chemical Sediments 2. Marine Carbonates - CaCO3 (limestone)
Chert (Quartz) – SiO2

29. Bedding – Layering or stratification in sedimentary rock

30. Fig. 7.25abc
W. W. Norton

31. Cross Bedding – water or wind

34. Ripple Marks

36. Sedimentary Environments

37. Sedimentary Systems and Plate Tectonics