1. Chapter 10 Sedimentary Rocks

2. Sedimentary Rocks Accumulations of various types of sediments Compaction: pressure from overlying sediments squeezes out air and water Cementation: dissolved minerals in water form a “glue” that holds sediments together

3. Sedimentary Rocks Classified by… Kind of sediments Size of sediments that form them

4. Clastic Sedimentary Rocks Rock fragments carried by wind, water, ice and deposited Classified by size

5. Clastic Conglomerate: Rounded gravel fragments or pebbles

6. Clastic Conglomerate wall

7. Clastic Breccia: Angular gravel fragments with sharp corners

8. Clastic Breccia wall

9. Clastic Sandstone: Sand-sized grains Mostly quartz Pore spaces- allow groundwater and oil to flow

10. Clastic Shale Clay-sized particles Cemented and compacted under pressure Flat, flaky layers

11. Chemical Sedimentary Rocks Minerals dissolved in water, settle out with change in temperature Ex. Limestone when calcite settles out of ocean water Evaporites: dissolved minerals left over when water evaporates; turns to rock

12. Chemical Ex: Gypsum, halite Ex: Great Salt Lake, UT

13. Organic Sedimentary Rocks Organic: formed from the remains of living things Ex: coal

14. Organic Limestone Shell build up on ocean floor, from Clams Oysters Plankton Ex: chalk

15. Organic White Cliffs of Dover, England

16. Sedimentary Rock Features Easily identifiable Include: Stratification (layering) Ripple marks Mud cracks Fossils Concretions

17. Stratification Change in type of sediment deposited Layers!! Vary in thickness

18. Stratification Cross bedding

19. Stratification Graded bedding: where in the layer do you think the largest and heaviest grains of sediment settle?

20. Ripple Marks Formed by action of wind or water on sand Preserved when sand  sandstone

21. Mud Cracks Formed when muddy deposits dry and shrink River plains, dry lake bed New deposits fill in

22. Fossils Remains or traces of ancient plants and animals Buried as sediments build up Hardest parts sometimes remain, but often dissolve into rock

23. Concretions Lumps, or nodules, of rock with composition different from main rock body Minerals precipitated from solutions build up around rock particles

24. Concretions Groundwater deposits quartz, calcite Geodes