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

2. The Earth’s resources were determined when the planet formed.

3. The Earth’s resources were determined when the planet formed.
Earth was formed roughyly 4.6 billion years ago.
Molten material slowly cooled, separated into layers based on mass.

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.

6. The Earth’s Layers
Asthenosphere- the outer part of the mantle, composed of semi- molten rock.
Lithosphere- the brittle outermost layer of the planet that is approximately 100 km thick. (smaller plates)

7. Checkpoint… How did Earth form?
What is the composition of each of Earth’s layers?
What is the practical significance today of the way Earth’s resources were distributed when the planted formed and cooled?

8. Earth is dynamic and constantly changing…
Earth’s geologic cycle consists of 3 major prcesses:
Tectonic cycle
Rock cycle
Soil formation

9. Convection and Hot Spots
The Earth is very hot at the center.
This heat causes plumes of hot magma to well upward from the mantle. (convection)
High temp. of mantle and outer core – due to radioactive decay.
Hotspots- places where molten material from the mantle reach the lithosphere.

10. Theory of Plate Tectonics
Plate tectonics- the theory that states that Earth’s lithosphere is divided into plates, most of which are in constant motion.
Alfred Wegener – German
meteorologist – 1912.
Pangea
Tectonic cycle – sum of the
Processes that build up and
Break down the lithosphere.
Continental vs Oceanic plates

11. Theory of Plate Tectonics

12. Tectonic Plates

13. Sea floor spreading – slow drifting of plates, rising magma forming new crust on seafloor.
Subduction – heavier oceanic plate sliding below lighter continental plate

14. Consequences of Plate Movement

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

16. Types of Plate Contact
Divergent plate boundaries- when plates move apart from one another. (sea-floor spreading)
OCEAN   OCEAN
Convergent plate boundaries- when plates move toward one another and collide. (subduction)
OCEAN---OCEAN OCEAN--CONTINENTAL
Transform fault boundaries- then plates move sideways past each other.
CONTINENTCONTINENT

20. Faults and Earthquakes
Faults- a fracture in rock across which there is movement.
Earthquakes- occur when the rocks of the lithosphere rupture unexpectedly along a fault.
(transform fault
boundary )

21. Faults and Earthquakes
Fault zone- large expanses of rock where movement has occurred.
Fault – fracture in rock where there is movement.
Epicenter- the exact point on the surface of Earth directly above the location where the rock ruptures.
Seismic activity occurs at fault zones or areas where earthquakes are common.

22. Environmental and Human Toll of Earthquakes and Volcanoes
Richter scale- a measure of the largest ground movement that occurs during an earthquake. The scale increases by a factor of 10, so an earthquake of 7 is 10 times greater than an earthquake of 6. (logarithmic)
Bill nye – Earthquakes!
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23. Check point… What is the theory of plate tectonics?
What are some environmental consequences of the tectonic cycle?
How do earthquakes and volcanoes occur?

24. The Rock Cycle
Rock cycle- the constant formation and destruction of rock.

25. (Constant formation and destruction of rock)
The Rock Cycle
(Constant formation and destruction of rock)
Rocks are the substance of the lithosphere
Rocks are composed of minerals
Minerals – solid chemical substances with uniform (often crystalline) structures that form under specific pressure and temp.
Can be made of compounds or one single element.

26. The Rock Cycle Igneous rocks- rocks that form directly from magma.
Intrusive igneous- form from within Earth as magma cools.
Extrusive igneous- from when magma cools above Earth. (ex. A volcano that ejects magma out will form this)
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.

28. Weathering and Erosion
Weathering- when rocks are exposed to air, water, certain chemicals or biological agents that degrade the rock.
Physical weathering- the mechanical breakdown of rocks and minerals.

29. Weathering and Erosion
Chemical weathering- the breakdown of rocks and minerals by chemical reactions.
Acid rain

30. 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.

31. Check point… What is the rock cycle?
What re the 3 basic rock pes, and how is each formed?
What is the difference between weathering and erosion? Why are both important?

32. Soil Mix of geologic and organic components.
Soil is 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

34. The Formation of Soil 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.

35. The Formation of Soil
Parent Material- the rock material from which soil is derived.

36. Soil Horizons
As soils form, they develop characteristics layers.

37. Soil Horizons
O horizon- (organic layer) composed of the leaves, needles, twigs and animal bodies on the surface.
A horizon- (topsoil) the zone of organic material and minerals mixed together.
B horizon- (subsoil) composed primarily of mineral material with very little organic matter
C horizon- (parent material) the least weathered horizon and is similar to the parent material.

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

39. Physical Properties of Soil
Porosity- how quickly the soil drains (which depends on its texture)

40. Chemical Properties of Soil
Cation exchange capacity (CEC)- the ability of a soil to adsorb and release cations, positively charged mineral ions.
Soil bases- calcium, magnesium, potassium and sodium
Soil Acids- aluminum and hydrogen
Base saturation- the proportion of soil bases (Calcium, magnesium, potassium and sodium) to soil acids

41. Chemical properties of soil…
With the exception of sodium, all bases are essential for plant growth

42. Biological Properties of Soil
Many organisms are found in the soil including fungi, bacteria, protozoans, rodents and earthworms. 42

43. Check point… How do soils form?
What are the roles of soils in ecosystems?
How do a soil’s physical and chemical properties influence its role as a medium for plant growth?

45. Elemental Composition of the Earth’s Crust45

46. Reserves
Reserves- the known quantity of a resource that can be economically recovered. 46

47. Types of Mining
Surface mining- removing minerals that are close to Earth’s surface.
Strip mining- removing strips of soil and rock to expose ore.
Open pit mining- the creation of a large pit or hole in the ground that is visible from the surface.
Mountain top removal- removing the entire top of a mountain with explosives.
Placer mining- looking for metals and stones in river sediments. 47

48. Types of Mining
Subsurface mining- mining for resources that are 100 m below Earth’s surface. 48

50. SURFACE MINING

51. Strip mining

52. Open pit mining

53. Mountain top removal

54. Placer mining

55. SUBSURFACE MINING

56. Reclamation

58. Checkpoint…
Why are economiocally valuable mineral resources distributed unevenly on the planet?
Describe the various types of surface mining.
What are the consequences of surface mining versus subsurface mining, and how has mining legislation tried to reduce those impacts?