1. Earth Systems and Resources
Chapter 8
Earth Systems and Resources

2. Are Hybrid Electric Vehicles as Environmentally Friendly as We Think?
Hybrid electric vehicles (HEV) and all-electric vehicles - most exciting innovations of the last decade?
Problem- contain neodymium, lithium, and lanthanum
Environmental trade-offs:
How we acquire scarce metals: Mining!
Mining involves ?
Extraction via surface mining  severe environmental impacts:
Why is this important?

3. The Earth’s resources were determined when the planet formed
Early Earth was a hot, molten sphere.
Molten material slowly cooled  elements within it separated into layers
Elements and minerals are distributed unevenly

4. The Earth’s Layers Core- the innermost zone of the planet
Made of nickel and iron
Mantle- above the core containing magma
Crust- the outermost layer of the planet

5. Scale of Earth’s Layers

6. The Earth’s Layers Asthenosphere- the outer part of the mantle
Lithosphere- the brittle outermost layer of the planet
Soil
Resources

7. Convection and Hot Spots
Earth  very hot at the center
Causes plumes of hot magma to well upward from the mantle
This produces:
Hotspots- places where molten material from the mantle reach the lithosphere
Convection cells in ____________________________

8. Theory of Plate Tectonics
German meterologist – Alfred Wegener
Pangeaea
Evidence
Wegener’s theory was replaced with:
Plate tectonics
Tectonic cycle

9. Tectonic Plates We know lithosphere is broken into plates
Oceanic plates
Continental plates
Oceanic and continental plates “float”
Subduction – the process of one plate moving underneath another plate

10. Geographic Time Scale As continents drifter over Earth’s surface…
Scientists use the fossil record to determine how organisms have adapted over time

11. Consequences of Plate Movement
Volcanoes- as a plate moves over a hot spot, rising magma forms a volcano

12. Types of Plate Contact Zones of plate contact:
Divergent plate boundaries- when plates move apart from one another
Convergent plate boundaries- when plates move toward one another and collide
Oceanic plates + continental plate
Transform fault boundaries- when plates move sideways past each other

13. Faults and Earthquakes
Faults- a fracture in rock across which there is movement due to plates moving
Fault zones
Earthquakes- occur when the rocks of the lithosphere rupture unexpectedly along a fault
Rapid movement

14. Faults and Earthquakes
Fault zones also called areas of ___________________
Epicenter- the exact point on the surface of Earth directly above the location where the rock ruptures.
Richter scale- a measure of the largest ground movement that occurs during an earthquake.
Both earthquakes and volcanos are disruptive to human life
Ie: Earthquake in Haiti (2010) and Etna Volcano in Italy (2001)

15. The Rock Cycle
Rock cycle- the constant formation and destruction of rock
Rock – composed of minerals
Minerals
Formation of rock
Weathering

16. The Rock Cycle Igneous rocks- rocks that form directly from magma
Classified by:
Chemical composition as basaltic or granite
Mode of formation: intrusive or extrusive
Sedimentary rocks- form when sediment such as mud, sands, or gravels are compressed by overlying sediments
Metamorphic rocks- form when sedimentary, igneous or other metamorphic rocks are subjected to high temperatures and pressures
Fractures

17. Weathering and Erosion
Weathering- when rocks are exposed to air, water, certain chemicals or biological agents that degrade the rock.
Include: physical processes, chemical processes, and erosion

18. Weathering and Erosion
Physical weathering- the mechanical breakdown of rocks and minerals
Caused by…
Chemical weathering- the breakdown of rocks and minerals by chemical reactions
Releases essential nutrients from rocks – now available for use by plants and other organisms
Some is the result of human activities

19. Erosion
Erosion- the physical removal of rock fragments from a landscape or ecosystem
Wind, water, ice transport and living organisms can erode materials
Deposition- the accumulation or depositing of eroded material such as sediment, rock fragments or soil

20. Soil Soil – mix of geologic and organic compounds Important because it
Is a medium for plant growth
Serves as a filter for water
A habitat for living organisms
Serves as a filter for pollutants

21. The Formation of Soil Takes hundreds to thousands of years
Soil results from physical and chemical weathering processes
Factors that determine the formation of soil:
Parent material- what the soil is made from influences soil formation
Climate- what type of climate influences soil formation
Topography- the surface and slope can influence soil formation
Organisms- plants and animals can have an effect on soil formation
Time- the amount of time a soil has spent developing can determine soil properties.

22. The Formation of Soil

23. Soil Horizons
As soils form, they develop characteristics layers (horizons)

24. Physical Properties of Soil
Texture- the percentage of sand, silt and clay the soil contains.

25. Physical Properties of Soil
Permeability - how quickly the soil drains (which depends on its texture)
Best agricultural soil is a mix of all three soil particles
Soil and pollution

26. Chemical Properties of Soil
Cation exchange capacity- the ability of a soil to adsorb and release cations, positively charged mineral ions
Clay particles attract positively charged mineral ions
Soil bases- calcium, magnesium, potassium and sodium
Promotes plant growth
Soil Acids- aluminum and hydrogen
Detrimental to plant nutrition
Base saturation- the proportion of soil bases to soil acids

27. Biological Properties of Soil
Many organisms are found in the soil
3 main groups of organisms = 80-90% of biological activity in soil
Detritivores
Soil fixing bacteria
Others:
Rodents and earthworms
Snails and slugs 27

28. Soil Degradation
Soil degradation – loss of some or all of the ability of soils to support plant growth
Occurs from overuse of land for agriculture, forestry and other human activities
Soil erosion
Compaction of soil by machines, humans and livestock
Extensive agriculture use and irrigation

29. Elemental Composition of the Earth’s Crust
Finite quantities of rocks, minerals and fossil fuels
Crustal abundance – average concentration of an element in the crust
Obtaining mineral resources:
Ores
Metals

30. Reserves
Reserves- the known quantity of a resource that can be economically recovered
Some reserves in US have already been depleted

31. Types of Mining

32. Types of Mining Surface Mining Subsurface Mining
Mineral and energy resources are extracted near Earth’s surface by removing soil, subsoil and over-lying rock strata
More common because less expensive
Two kinds: open pit and strip mining
Subsurface Mining
Mineral and energy resources are extracted from deep underground deposits
Two kinds: shaft mine and slope mine 32

33. Types of Mining

34. Types of Mining
Mountain top removal- removing the entire top of a mountain with explosives
Problem – damage to streams and nearby groundwater cannot be rectified by the reclamation process
Placer mining- looking for metals and stones in river sediments

35. Mining Laws Effectiveness has varied
Mining Law of 1872 – goal to regulate the mining of silver, copper, and gold ore as well as fuels, including natural gas and oil, on federal lands
The Surface Mining Control and Reclamation Act of regulates surface mining of coal and the surface effects of subsurface coal mining