True or False: The Earth’s surface has stayed the same for thousands of years

1. True or False: The Earth’s surface has stayed the same for thousands of years

2. True or False: The Earth’s surface has stayed the same for thousands of years False The Earth’s surface is always changing!

7. Weathering and Erosion Wind Water Ice Gravity

8. Objectives Briefly contrast weathering and erosion. Contrast chemical and mechanical weathering. List and describe the types of mechanical weathering. List and describe the types of chemical weathering. List the products resulting from the chemical weathering of Igneous rocks. List and discuss the factors that influence the type and rate of rock weathering.

9. The Rock Cycle What kinds of rock can be melted? Can be weathered & eroded? Heated & Pressurized?

10. Weathering and Erosion Weathering - processes at or near Earth’s surface that cause rocks and minerals to break down Erosion - process of removing Earth materials from their original sites through weathering and transport

11. Weathering • Breakdown of rock due to surface processes • 2 types of weathering • Physical (Mechanical) • Chemical

12. Physical Weathering • Abrasion - wind & water • Frost wedging - water expands when it freezes • Exfoliation or unloading – • rock breaks off into leaves or sheets along joints which parallel the ground surface; • caused by expansion of rock due to uplift and erosion; removal of pressure of deep burial • Thermal expansion - • repeated daily heating and cooling of rock; • heat causes expansion; cooling causes contraction. • different minerals expand and contract at different rates causing stresses along mineral boundaries. • Plant Roots – break rocks apart as they grow • Salt Crystal Growth–evaporation, crystals grow between rocks

13. Type of physical weathering?

14. Type of physical weathering?

15. Exfoliation

16. Dome Exfoliation

17. Type of physical weathering?

18. Type of physical weathering?

19. Type of physical weathering?

20. Type of physical weathering?

21. Type of physical weathering?

22. Plant Wedging

23. Type of physical weathering?

24. Frost Wedging

25. Chemical Weathering Rock reacts with water, gases and solutions (may be acidic); will add or remove elements from minerals. 1. Dissolution (or solution) - also includes leaching 2. Oxidation 3. Hydrolysis 4. Biological Action 5. Spheroidal

26. Acid Rain

27. Dissolution • Several common minerals dissolve in water • halite • calcite • Limestone and marble contain calcite and are soluble in acidic water • Marble tombstones and carvings are particularly susceptible to chemical weathering by dissolution.

28. More Dissolution Caves and caverns typically form in limestone • speleothems - cave formations; made of calcite • form a rock called travertine • stalactites - from ceiling • stalagmites - on ground

29. More Dissolution Karst topography forms on limestone terrain and is characterized by: • caves/caverns, • sinkholes, • disappearing streams, • springs

30. Acid Leaching