1. BIG IDEA 6: Earth Structures
Description   Over geologic time, internal and external sources of energy have continuously altered the features of Earth by means of both constructive and destructive forces. All life, including human civilization, is dependent on Earth's internal and external energy and material resources.

2. Benchmark Number & Descriptor
SC.7.E.6.1
Describe the layers of the solid Earth, including the lithosphere, the hot convecting mantle, and the dense metallic liquid and solid cores.
SC.7.E.6.2
Identify the patterns within the rock cycle and relate them to surface events (weathering and erosion) and sub-surface events (plate tectonics and mountain building).
SC.7.E.6.3
Identify current methods for measuring the age of Earth and its parts, including the law of superposition and radioactive dating.
SC.7.E.6.4
Explain and give examples of how physical evidence supports scientific theories that Earth has evolved over geologic time due to natural processes.
SC.7.E.6.5
Explore the scientific theory of plate tectonics by describing how the movement of Earth's crustal plates causes both slow and rapid changes in Earth's surface, including volcanic eruptions, earthquakes, and mountain building.
SC.7.E.6.6
Identify the impact that humans have had on Earth, such as deforestation, urbanization, desertification, erosion, air and water quality, and changing the flow of water.
SC.7.E.6.7
Recognize that heat flow and movement of material within Earth causes earthquakes and volcanic eruptions, and creates mountains and ocean basins.

3. INSIDE THE EARTH

4. EARTH’S LAYERS The Earth is divided into FOUR main layers: Crust
Mantle
Outer Core
Inner Core

5. EARTH’S CRUST Outer layer of Earth’s surface Makes up 1% of Earth
2 types of crust:
Oceanic
Continental
Earth’s crust is broken down into pieces known as tectonic plates.

6. Mantle Earth’s largest layers
Made mostly of silicon, oxygen, magnesium and iron
Pieces of mantle can be obtained by erupting volcanoes.

7. OUTER CORE Is about 3000 miles beneath the Earth’s crust
Said to be made up of molten lava
Iron
Nickel
This lava flows very slowly inside the Earth, creating a magnetic field.

8. INNER CORE Deepest part of Earth Smallest section inside Earth
Solid mass due to intense pressure
composed of iron and nickel

9. BOUNDARIES between LAYERS
Moho Discontinuity
Located between the crust and mantle
Plastic Like Layer
Part of the upper mantle
Shadow Zone
Part of the liquid outer core

10. KNOWLEDGE CHECK How many layers make up Earth?
Which layer of Earth contains tectonic plates?
Which is Earth’s largest layer?
Which elements in Earth’s core helps create a magnetic field?

11. KNOWLEDGE CHECK How many layers make up Earth? 4
Which layer of Earth contains tectonic plates? Earth’s crust
Which is Earth’s largest layer? Mantel
Which elements in Earth’s core helps create a magnetic field? Nickel and Iron

12. It’s Just a little rock.

13. Earth’s Past and Future
Earth has been transforming for the past 4.5 million years.
The energy for this constant transformation comes from the Earth's molten interior.
Earth will probably continue to evolve for another 4-5 billion years into the future.
This energy from Earth’s interior has driven the Earth's physical/chemical evolution, and been ultimately responsible for all the rocks, continents, mountains, foreland basins, etc.

14. The Rock Cycle Rocks are naturally occurring.
Rocks contain minerals, organic material, and glass.
There are 3 types of rocks:
Igneous
Metamorphic
Sedimentary
Each type of rock can become a new type by traveling through the rock cycle.

15. IGNEOUS ROCKS Origins: Types of Lava/Magma:
Come from volcanoes
When magma(inside)/Lava (outside) cool
Types of Lava/Magma:
Due to location of Volcano
Basaltic – Hawaii, non-explosive volcanoes
Andesitic – Pacific ocean volcanoes
Granitic – very explosive volcanoes
Categories of Igneous Rocks:
Intrusive
Formed inside Earth
Found when volcano erupts and are pushed out or through mining
Contain large mineral grains
Extrusive
Form outside surface
Lava cools quickly
Rocks generally contain holes; gas escapes

16. EXAMPLES OF IGNEOUS ROCKS
Granite: Igneous, Intrusive
Obsidian - volcanic glass that is formed by very rapid cooling of lava
Pumice is lava that had a lot of gases in it and cooled quickly on the surface of the Earth.

17. METAMORPHIC ROCKS Origin:
Rocks that form from change in temperature and pressure
Earth Processes:
Heat and Pressure
Rocks are beneath the surface; heat and pressure increases.
Rocks do not melt, but they do exchange minerals creating new rocks.
Fluids
Fluids carrying dissolved minerals react with rocks.
Chemical reaction occurs, and new rocks are formed.
Earth’s Relation
They can form from tectonic processes such as continental collisions.
They are also formed when rock is heated up by the intrusion of hot magma from the Earth's interior.
Metamorphic rocks become exposed at the Earth's surface by erosion and uplift.
Studying metamorphic rocks tells us about the temperatures and pressures that occur at great depths within the Earth's crust.

18. EXAMPLES OF METAMORPHIC ROCK
Foliated
Mineral grains are flattened into layer.
Example - GNEISS: A foliated rock usually made from some type of granite
Non-Foliated
Smooth texture, no layers
Example - Quartzite

19. SEDIMENTARY ROCKS Rocks created from sediments.
Materials that make up sediments:
Weathered and eroded rock
Plant and animal remains
Minerals that fall out of solution
Relationship to Earth
Sediments are formed by both weathering and erosion.
Sediments are then transported to their place of deposition by water, wind, mass movement, or glaciers.
Ways sedimentary rocks form:
Compaction
Sediments are pressed together.
Cementation
Sediments are glued together.
Deposition of minerals
Minerals in solution are left when water evaporates.

20. EXAMPLES OF SEDIMENTARY ROCKS
DETRITAL:
Made of broken fragments of other rocks
CHEMICAL:
Made of minerals dissolved in solution
BIOCHEMICAL:
Made of the remains of once-living things
Breccia composed of sharp angled fragments
Rock Salt: This is an evaporate after the water evaporated from saltwater.
Fossillferous Limestone contains fossils of various fresh and or salt water shell fish.

21. KNOWLEDGE CHECK Where is the beginning of the rock cycle?
NAME THAT ROCK:
This rock is formed from organic, inorganic, and rock fragments.
This rock is formed from heat and pressure.
This rock is formed from molten lava/magma.

22. KNOWLEDGE CHECK
Where is the beginning of the rock cycle? It is a cycle; therefore, there is no true beginning or end.
NAME THAT ROCK:
This rock is formed from organic, inorganic, and rock fragments. Sedimentary
This rock is formed from heat and pressure. Metamorphic
This rock is formed from molten lava/magma. Igneous

23. HOW OLD IS THIS BIG ROCK?

24. HOW OLD IS EARTH? Rocks are an open window to Earth’s past.
James Hutton (18th century) believed Earth had to be much older then what was originally thought – probably millions of years old.
He proposed his principle of Uniformitarianism.
Big Idea:
Geological processes that we see occurring today are the same processes that occurred in the past.

25. DATING EARTH LAW of SUPERPOSITION
Superposition refers to, “placing on top of each other.”
Scientists use the Law of Superposition to determine whether a fossil or a layer of rock is older or younger than another fossil or layer of rock.
This law states that in a series of sedimentary rock layers, younger rocks normally lie on top of older rocks.

26. DATING EARTH RADIOACTIVE DATING Carbon – 14
Scientist use the decay of radioactive elements to determine the age of rocks.
Radiometric dating indicates that the Earth is about billion years old
Radioactive Decay:
Unstable elements that breakdown, or decay, by releasing particles and energy in the process and form another element
Carbon – 14
Used to find the absolute age of rocks
Carbon-14 has a half-life of 5730 years.
It is only useful for dating materials that contain Carbon and lived no more than 50,000 years ago.

27. KNOWLEDGE CHECK Describe the principle of Uniformitarianism.
When looking at a cross-section of the Grand Canyon, layers are noticed. What law best describes these layers?
What element must be present in order to use radioactive dating?

28. KNOWLEDGE CHECK
Describe the principle of Uniformitarianism. Geological processes that we see occurring today, are the same processes that occurred in the past.
When looking at a cross-section of the Grand Canyon, layers are noticed. What law best describes these layers? Law of Superposition
What element must be present in order to use radioactive dating? Carbon-14

29. WHY DOES EARTH LOOK THE WAY IT DOES?

30. HOW DID THAT GET HERE? The Earth is said to be 4.57 billion years old.
In order for Earth to look the way it does today many factors are taken into consideration.
Physical geology is the study of the Earth's rocks, minerals, and soils and how they have formed through time.
Complex internal processes such as plate tectonics and mountain-building have formed these rocks and brought them to the Earth's surface.
Earthquakes are the result of the sudden movement of crustal plates, releasing internal energy that becomes destructive at the surface.
Internal heat and energy are released also through volcanic eruptions.
External processes such as glaciation, running water, weathering, and erosion have formed the landscapes we see today.

31. EVIDENCE of EARTH’S EVOLUTION
TYPES of EVIDENCE
EXAMPLES of EVIDENCE
Evidence located at PLATE BOUNDARIES
Evidence left behind from WEATHERING
Evidence left behind from EROSION AND DEPOSITION
Himalayas, Andes, Hawaiian Islands – all found at different plate boundaries.
Stalactites and stalagmites are the remains of rocks which went through chemical weathering.
Gullys, deltas, valleys, sand dunes, landslides are created through time as a result of moving water, ice, wind, and gravity.

32. EVIDENCE of EARTH’S EVOLUTION
TYPES of EVIDENCE
EXAMPLES of EVIDENCE
Evidence from LANDFORMS - PANGEA
Evidence of FOSSILS
Evidence from CLIMATE
Mountain ranges in Africa line up with those in South America.
Fossils of the plant Glossopteris found in rocks on widely separated landmasses
Fossils of tropical plants found near Arctic Circle

33. KNOWLEDGE CHECK Approximately how old is planet Earth?
List and explain 4 pieces of evidence supporting Earth’s evolution.

34. KNOWLEDGE CHECK
Approximately how old is planet Earth? The Earth is said to be 4.57 billion years old.
List and explain 4 pieces of evidence supporting Earth’s evolution.
Pangaea – Super continent
Fossils – Similar fossils found in different areas
Erosion and Deposition – formation of gullies, deltas, valleys, etc.

35. WE’RE FLOATING ON PLATES?

36. PLATE TECTONICS
The Earth’s crust and upper mantle are broken into sections called plates.
Plates move around on top of the mantle like rafts in a pool.
Earth’s plates are located on the lithosphere (crust and upper mantle).
The average thickness of a plate is 100 km (62 miles).
Most plates support both continent and ocean.

37. Alfred Wegener
Proposed a theory stating that in the distant past, the Earth’s continents were all joined as a single landmass.
When Wegener placed all the continents together like a puzzle, it formed a large landmass which he called Pangaea.
Wegener stated that this supercontinent began to break up about 200 million years ago.

38. PLATE BOUNDARIES
Earth’s crust is made up of 7 major plates and several smaller ones.
Where the edges of these plates meet is known as a PLATE BOUNDARY.
How the plates are moving determines what type of boundary is between them.

39. TYPES of BOUNDARIES CONVERGENT BOUNDARY
Plates collide into each other.
These collisions produce mountains, earthquakes, and volcanoes.
Example:
Andes Mountains
Aleutians Islands
CONVERGENT BOUNDARY

40. 3 TYPES of CONVERGENT BOUNDARIES
Ocean plate colliding with a less dense continental plate
Subduction Zone: where the less dense plate slides under the more dense plate
VOLCANOES occur at subduction zones.
Example: Andes Mountains
2. Ocean plate colliding with another ocean plate
The less dense plate slides under the more dense plate creating a subduction zone called a TRENCH
Example: Aleutian Islands
3. A continental plate colliding with another continental plate
a place where folded and thrust faulted mountains form
Example: Himalayas

41. CONVERGENT BOUNDARIES
TYPE 2
TYPE 1
TYPE 3

42. TYPES of BOUNDARIES DIVERGENT BOUNDARY
Plates move away from each other.
Most of these boundaries are found in the oceans.
At divergent boundaries, mid-ocean ridges and rifts are formed.
DIVERGENT BOUNDARY

43. DIVERGENT BOUNDARY
The best known of the divergent boundaries is the Mid-Atlantic Ridge.
This submerged mountain range extends from the Arctic Ocean to beyond the southern tip of Africa.
The rate of spreading along the Mid-Atlantic Ridge averages about 2.5 centimeters per year (cm/yr) or 25 km in a million years.

44. TYPES of BOUNDARIES TRANSFORM BOUNDARY
Plates slide past each other.
The sliding of these plates causes rocks to rub against each other. At times, these rocks break and inch past each other. These breaks are felt as earthquakes.
TRANSFORM BOUNDARY

45. TRANSFORM BOUNDARY
The San Andreas Fault is a result of the Pacific and North American plates sliding past each other.
These plates are moving at about 5cm a year.

46. KNOWLEDGE CHECK Explain the theory of plate tectonics.
How many plate boundaries are there?
Name the type of plate boundary each feature is located at:
Andes Mountains
Mid-Ocean Ridge
San-Andrea’s Fault

47. KNOWLEDGE CHECK
Explain the theory of plate tectonics. Earth’s crust is broken up into plates which float on top of the mantle. The plates support the continents and oceans.
How many plate boundaries are there? types of plate boundaries
Name the type of plate boundary each feature is located at:
Andes Mountains - Convergent
Mid-Ocean Ridge - Divergent
San-Andrea’s Fault - Transform

48. MOUNTAINS, VOLCANOES, EARTHQUAKES – HOW THEY FIT IN THE PICTURE

49. Convection Currents
Hot magma in the Earth moves toward the surface, cools, then sinks again.
This movement creates convection currents beneath the plates that cause the plates to move.
When the plates move, mountains, earthquakes, and volcanoes form.

50. MOUNTAINS
Mountains are formed when uplift occurs (Forces within the crust lift the land above).
3 types of mountains can form due to plate movement:
Folded mountains
Fault-Block mountains
Volcanic mountains
Yes, volcanoes are considered mountains.

51. FAULT-BLOCK Mountains
MOUNTAIN FORMATION
FOLDED Mountains
FAULT-BLOCK Mountains
Folded mountains are formed by crust which have been uplifted and folded by compressional forces.
These mountains occur along convergent plate boundaries either between continental plates or between an oceanic and a continental plate.
Examples:
Rockies
Andes
Alps
Himalayas
These mountains form when faults or cracks in the Earth's crust force some materials or blocks of rock up and others down.
Instead of the Earth folding over, the blocks are stacked.
Examples:
Sierra Nevada Mts.
Harz Mts.

52. VOLCANOES INFORMATION WHY THEY EXPLODE
Volcanoes form when material from inside the Earth reaches the surface.
Magma: Molten rock found inside the Earth
Lava: Molten rock when outside surface is reached
Volcanoes are most commonly found at both convergent and divergent plate boundaries.
A major belt of volcanoes is the “Ring of Fire” which encircles the Pacific Ocean.
Temperatures in the mantle are hot enough to melt rock into magma .
Since magma is less dense than the solid rock around it, magma rises and some of it collects in magma chambers.
As the magma rises, pressure decreases allowing trapped gasses to expand and propel the magma through openings in the Earth’s surface causing an eruption.

53. 3 TYPES OF VOLCANOES SHEILD VOLCANOES CINDER CONE VOLCANOES
Broad shaped, quiet eruptions
Examples: Kilauea, Hawaii and Mt. Etna, Italy
CINDER CONE VOLCANOES
Steep sided, explosive eruptions (usually throws lava and rock high into the air)
Example: Paricutin, Mexico
COMPOSITE VOLCANOES
Steep sided, eruptions vary from quiet to explosive
Example: Mt. St. Helens

54. 1943 Eruption of Paricutin – Mexico
TYPES OF VOLCANOES
1943 Eruption of Paricutin – Mexico
Cinder cone Volcano
Mt. Etna, Italy
Shield Volcano
Mt. St. Helens, 1982
Composite Volcano

55. ENVIRONMENTAL EFFECTS
Earth’s surface is greatly affected by volcanoes.
LAND
AIR
WATER
Lava
Poisonous gasses
Hot Springs
Volcanic Ash
Acid Rain
Geysers
Landslides
Haze
Deep Sea Vents
Mudflows
Lower Temps
Fumaroles

56. EARTHQUAKES
Earth’s crust movement causes stress among rocks under its surface.
Stress can cause rocks to bend and stretch.
Eventually rocks will break away from one another.
Area in which the rocks break and move is called a fault.
When rocks break, vibrations are produced called an earthquake.

57. Elastic Rebound Theory
Explains how energy is stored in rocks
Rocks bend until the strength of the rock is exceeded.
Breaks occurs and the rocks quickly rebound to an undeformed shape.
Energy is released in waves that radiate outward from the fault.
Fault: surface that rocks/plates move along

58. ROCKIN ‘N’ ROLLIN FOCUS SEISMIC WAVES
Location where the earthquake energy is released inside the Earth.
At the focus, seismic waves are produced and sent out.
What we feel
Primary Waves (P Waves)
Travel through rocks
Take a straight path
Move the fastest
Secondary Waves (S Waves)
Causes rocks to vibrate
Takes a straight path
Rocks move up/down
Surface Waves
Move above ground
Move up/down and side/side
Causes destruction
Travels the slowest

59. WHAT’S the DAMAGE SEISMIC WAVES OTHER DANGERS
The damage from earthquake waves depends on several factors.
Intensity and duration of the vibrations
The nature of the material on which the structure is built
The design of the structure
Tsunami
The ocean floor moves vertically along a fault.
The vibration of a quake sets an underwater landslide into motion.
Landslides
The greatest damage to structures is from landslides and ground subsidence.
The sinking of the ground can also be triggered by vibrations.

60. KNOWLEDGE CHECK What causes plates to move on the mantle’s surface?
What force causes mountains to form?
What type of boundaries are most common to find volcanoes?
List 3 ways volcanoes change Earth.
Where land moves and breaks is known as?
Which type of Seismic Waves causes the most damage?

61. KNOWLEDGE CHECK
What causes plates to move on the mantle’s surface? Convection currents
What force causes mountains to form? Uplift
What type of boundaries are most common to find volcanoes? Convergent and Divergent
List 3 ways volcanoes change Earth. Air pollution, acid rain, geysers
Where land moves and breaks is known as? Faults
Which type of Seismic Waves causes the most damage? Surface Waves

62. It’s Not Just Nature Changing our EARTH

63. ENVIRONMENTAL POLLUTION
TYPES of POLLUTION
Pollution is the harmful alteration of our environment by our own actions.
People depend on biological diversity for the quality of their lives.
Air Pollution
Caused by the burning of fossil fuels
Water Pollution
Sewage, chemicals, etc.
Land Pollution
Pesticides, herbicides, garbage
Global Warming
Ozone depletion

64. Threat to the Ecological Balance
VEGETATION
SOIL
Vegetation is a source of food, building material, fuel, and medicine.
Destruction of vegetation:
Fire
clearance of vegetation, soil erosion, flooding, and wind erosion
Deforestation
Ecosystems, nutrient cycles are affected as well as a loss of biodiversity
Soil is unique in that it depends on plants and vegetation for its existence, yet plants depend on soil for their support, air, water, and nutrients.
Destruction of soil:
Soil compaction
Prevents plant growth and encourages erosion
Erosion of soil
Increases flooding, landslides, and increases sediment loads leading to silting up of reservoirs

65. Threat to the Ecological Balance
OCEANS
LANDSCAPE
The ocean has the greatest biodiversity anywhere on the planet.
Destruction of oceans and its contents:
Over fishing
The depletion of fish in one area can cause the destruction of marine ecosystems.
Water pollution
Caused by untreated sewage, oil, industrial chemicals, and radioactive waste
Over the past century, humans have radically altered the face of the Earth.
Destruction of land:
Mining
Pulling out natural resources
Dumping of waste
Building
Causes loss of habitat by harvesting natural resources - Urbanization

66. Threat to the Ecological Balance
AIR
WATER QUALITY
Sources of air pollution are volcanoes, factories, and cars (both human and natural activities).
Destruction of Air Quality:
Greenhouse Effect
When fossils fuels are burned, excess carbon dioxide is created resulting in the depletion of the ozone layer – Global Warming
Surface and groundwater contamination come greatly from factories, homes and farms.
Destruction of Water Quality:
Water Contamination
Fertilizers, insecticides, and fluids from cars run off into ponds, rivers, and streams contaminating them.
Some of this polluted water seeps into the ground contaminating our drinking water.

67. KNOWLEDGE CHECK
Why is it important to keep a balance between humans and their ecosystem?
Identify the action with the location:
Deforestation A. Water Quality
Fertilizers B. Oceans
Urbanization C. Landscape
Acid Rain D. Air
Increased Carbon Dioxide E. Vegetation

68. KNOWLEDGE CHECK
Why is it important to keep a balance between humans and their ecosystem? People depend on biological diversity for the quality of their lives.
Identify the action with the location:
Deforestation E A. Water Quality
Fertilizers A B. Oceans
Urbanization C C. Landscape
Acid Rain B D. Air
Increased Carbon Dioxide D E. Vegetation