Topic 3, Section 1: Elementary Plate Tectonics Rocks and Weathering Topic 3, Section 1: Elementary Plate Tectonics

The Earth’s Interior What is the plate tectonic theory? Outline and describe the Earth’s layers.

Plate Tectonics Explain continental drift. What is the evidence? Describe the theories for plate movement.

Processes & Landforms Describe and explain sea-floor spreading. What are ridges?

Subduction Zones Explain what transpires in subduction zones. Describe deep-sea ocean trenches.

Explain mountain formation. Mountain Building Explain mountain formation.

Volcanic Island Arcs Discuss ocean ridges. Outline and explain how island arc systems are formed.

Final Points The reason why ridges are elevated above the ocean floor is that they consist of rock that is hotter and less dense than the older, colder plate. Spreading rates are not the same throughout the ocean system; they vary. Subduction zones dip mostly at angles between 30 and 70 degrees. Individual subduction zones, however, dip more steeply with depth. The dip of the slab is related inversely to the velocity of convergence at the trench, and is a function of the time since the initiation of subduction. The older the crust, the steeper it dips. Because the down-going slab of lithosphere is heavier than the plastic asthenosphere below, it tends to sink passively.

Topic 3, Section 2: Weathering and Rocks Rocks and Weathering Topic 3, Section 2: Weathering and Rocks

Opening Questions What is weathering? Define chemical, mechanical (physical), and biological weathering. Outline the key features of weathering.

Physical Weathering Describe freeze-thaw. Discuss salt crystallization. How does disintegration occur? Explain pressure release. What can vegetation roots do?

Chemical Weathering Explain solution’s importance to chemical weathering. How does carbonation-solution occur? Explain how hydrolysis happens. Describe hydration.

Weathering Controls Explain Van Hoff’s Law. Discuss how rock type and structure, vegetation, and relief affect weathering.

Final Point In general, frost shattering increases as the number of freeze-thaw cycles increases rather than according to average temperatures. By contrast, chemical weathering increases with moisture and heat.

Topic 3, Section 3: Slope Processes and Development Rocks and Weathering Topic 3, Section 3: Slope Processes and Development

Opening Questions Define and describe slopes. How do climate and geological structure affect slopes? Define regolith, soil, and aspect. Explain how vegetation affects slopes.

Mass Movements Describe the types of mass movements. What factors determine slope movement?

Shear Strength & Resistance Define shear strength. Define shear stress. What is water’s role?

Heave or Creep Define and describe heave or creep. What triggers this movement?

Slumps & Flows What causes slumps? Outline and describe the various flow types. Discuss the Sidoarjo case study.

Slides Explain how slides transpire. Discuss the Mexican landslides case study.

Abbotsford Landslide Case Study Discuss the landslide. Explain why it happened. What are the lessons learned?

Falls How do falls occur? Describe the variations of falls.

Water Movement Describe and explain surface wash. Describe and explain sheet wash. Discuss rainsplash erosion.

Final Points Students, in the past, have stated that north-facing slopes are colder than south-facing slopes. This is only true in the northern hemisphere. The reverse is true in the southern hemisphere. Weak rocks, like clay, have little shear strength to begin with, and are vulnerable to the development of slip planes. Slip planes are typically a concave curve and as slide occurs, the mass will be rotated backwards.

Topic 3, Section 4: The Human Impact Rocks and Weathering Topic 3, Section 4: The Human Impact

Opening Questions How much of an impact do humans have on the environment and landforms? What about mother nature?

Strategies for Reduction How do humans alter mass movement rates? Discuss the strategies to reduce mass movements.

Strategies for Reduction Describe and explain the link between human interferences and naturally occurring processes.

Hong Kong Case Study Discuss why Hong Kong as a long history of landslides. Explain the geology and how the gov’t manages landslides and slopes.

Brazil Case Study Describe and explain the area’s vulnerability to landslides. Discuss the responses to the January 2011 landslide.