1. GEOLOGY ROCKS!

2. Evidence you can see everyday!
How do we know that Earth is changing?
Look to the ground!

5. Classification: Igneous Rock Notes (~pg.180)
Intrusive
Magma cools SLOWLY beneath earth’s surface.
Forms large crystal/mineral grains
Extrusive
Lava cools QUICKLY above earth’s surface
Forms Fine-grain rock
Ex: Basalt, Obsidian
Glassy looking…
3 Families based on Composition:
Granite-Basalt-Diorite
-Granite: Felsic- high in silica
Light coloring
-Basalt: Mafic- low in silica, rich in iron
Darker Coloring
-Diorite: little/no Quartz

6. Igneous Rocks
Composition: Magma/lava is a mixture of elements such as silica, iron, sodium, potassium, etc.
Fine or Coarse Grained
How they are made:
As the magma/lava cools these elements chemically combine, or crystallize, in geometric patterns to form the eight rock forming minerals.

7. Igneous

8. How they are formed:
Igneous rock: Latin “from fire” rock formed when magma cools and hardens.
Ex: Pumice, Obsidian
Sedimentary rock: small fragments of all types of rocks compressed and cemented together.
Fossils found here, inorganic
Ex: sandstone
Metamorphic rock: meaning “changed form”. Rock that has been changed by pressure, heat, or chemical processes.
Ex: Marble

9. Sedimentary Rock
Clastic rocks –cemented sediments made up of fragments brought by wind/water/ice.
Chemical- rock formed from minerals dissolved in water
Organic- rock formed from remains of organisms
Classified on two criteria - texture (grain size), and composition

10. Sedimentary 3 Categories
Clastic
Classified by sediment size
Conglomerate
Breccia
Sandstone
Shale (flaky/clay-sized grain)
Chemical
Minerals dissolved in water.
Precipitate (settles out) or what's left behind after evaporation.
Ex’s Gypsum, halite
Organic
Formed from the remains of living things.
Ex: Coal, Limestone (chalk)

11. Sedimentary? IDENTIFICATION Stratification (layering) Ripple Marks
Stratified rock in Utah
Sedimentary?
IDENTIFICATION
Stratification (layering)
Ripple Marks
Mud Cracks
Fossils
Concretions (lumps/nodules)

13. The texture can be non-foliated or foliated.
Metamorphic Rock
Classified by texture and composition.
The texture can be non-foliated or foliated.
Foliated - banded or layered.
made when extreme pressure flattens the mineral crystals.
Foliated rocks can be made when minerals of diff. densities separate into bands (lightdarklightdark)
Ex’s
Slate Schist  Gneiss
Rock changes with greater metamorphosis
Metamorphic Rock Pictures:

14. Unfoliated Rocks
No bands of crystals-Heat and Pressure change the parent rock.
For example… Sandstone (sedimentary) changed to Quartzite
Ex: Marble
How metamorphic rock made? Pg Parent rock is put under extreme Heat and Pressure!!
Hot fluids can cause
#1 way of making metamorphic rock= Regional Magma – Regional Metamorphism …flow and pressure

16. Go to PDF rock cycle notes

18. Check your 1st and last columns in your notes 

19. Rock Identification Lab
Choose 2 rocks from each box to observe.
Move to the next station and choose 2 rocks to observe.
Move to the final station and choose 2 more rocks to observe.
You should have 2 sedimentary, 2 igneous, and 2 metamorphic samples.
Helpful hint: Choose a sample close to 1 and one close to 15…
and the sketches must be colored!!
Characteristics to possibly include:
Luster (shiny, dull) Size of Crystals (if present)
Density (feels heavy, light) Texture (fine or coarse grained)
Fracturing (cleavage-how it looks if it were cracked)
Intrusive-Extrusive-Clastic-Organic-Chemical-Foliated-NonFoliated.

20. So it makes sense that…
Fossils are found most commonly in sedimentary rocks
Surrounding volcanoes we find lots of igneous rocks
Near plate boundaries, where there is lots of stress and pressure on rocks we find metamorphic rocks

21. How do “rocks” look?
Complete the ROCK IDENTIFICATION lab in your packet…then
Complete the Rock Cycle worksheet in your packet!
VIDEO LINK: Rock of the Ages
Geologic Time (9 minutes)

22. How Earth is Shaped… Plate tectonics
Unit 8
Ch’s 4

24. Earth’s Layers Song!!!! http://www.youtube.com/watch?v=Q9j1xGaxYzY
(2min 45sec.)

25. Another graphic of Earth’s interior : Causes in Plate Motion
Convection: The transfer of heat through movement of heated fluid material.

26. Earth’s Layers Crust (oceanic and continental) Mantle Core
Lithosphere: Crust & upper part of the mantle
Asthenosphere
Plastic- bottom part of mantle
heat makes the mantle gooey.

27. Bill Nye’s Greatest Discoveries in Earth Science
One theory is that convection within the Earth's mantle pushes the plates
Bill Nye’s Greatest Discoveries in Earth Science
1st 10 min. minutes

28. Deformation of the Crust

29. Types of Stress:
Compression- pushing together (plates moving together)
Tension- pulling apart (plates moving apart)
Shearing- grinding next to or past each other

31. Stress can cause the crust to:
Fold- bends in rock but there is no break
Anticlines (compression)
Synclines (tension)
Monoclines (shearing or too old to tell)
Fault- break/crack in the rock

33. Anticline

34. Syncline
“smile”

36. In Conclusion…because of stresses
The crust twists and bends under pressure and strain (stress) so it moves a lot!
Movement of Plates
Isostatic Adjustments to balance pressure between the crust and mantle
“add” to the crust (mountains, glaciers, etc) and it “sinks farther into the mantle

37. As a result of stress, mountains can be several types:
Folded- Usually from continents colliding
Can have faults but generally formed from being squeezed together
Appalachians, Himalayas
Fault-Block- Crust broken into large blocks, the blocks get tilted and shoved
Rockies

38. Volcanic- Built up material from volcanoes
May be on convergent boundary or hot spot
Hawaii, most mountains on west coast of U.S., Pacific Ring of Fire Mountains (Andes, Mt.Fuji, etc)
Dome Mountain- magma wells up to surface and pushes up the crust without breaking through, then hardens, crust erodes leaving dome mountain
Half Dome, Yosemite Park, CA
Upstate New York

39. Observations are made and
People start to wonder….
What has shaped the surface of the Earth?

40. How is the world shaped? 1st Theory…..Earth was shaped by catastrophe?
Volcanoes
Earthquakes
Floods
WEATHERINGVideo Clip
Layers of rock - TIME
How old is the earth????
Radiometric Dating (Ex: Decaying Uranium lead)

41. Dude, we are all drifting.
4.1 Continental Drift
Maps seem to show relationships between continents.
Alfred Wegener in 1912, proposed Continental Drift. Meaning…
continents move!
Dude, we are all drifting.

42. Continents once were all part of 1 landmass called Pangea
Pangea web link
Pangea= all lands
Panthalassa= all waters (ocean surrounding Pangea)

43. Evidence of CD Formerly adjoined parts have similar fossils.
Ex: Mesosaurus
Geologic similarities
(Mountain Ranges Connect & Mountain building)
Ex: Mts. In Eastern U.S. & Greenland; Himalayas
Climatic patterns are explained
Ex: coal deposits in eastern U.S., Siberia & Europe
(need tropical climates for coal formation)

44. Fossil Evidence Examples

45. Is that everything?... Let’s review the evidence
*Continental shelves fit together like a puzzle
*Continuous mountain ranges if continents are together
*Fossils matched across continents
*Continuous glacial striations (scratches)
*Rock layers matched across continents
What else? Well…..

46. The final piece of evidence…
Seafloor Spreading
Harry Hess (
Mid- Atlantic Ridge
Rocks are older the farther they are from the ridge
-ridges are areas of crust renewal
- seafloor moves away from ridges
Conclusion:
If seafloor is moving, then so are the continents !
SO…. Which direction do plates move and why?????

47. Sea Floor Spreading

48. Mid-Ocean Ridges

50. 4.2 The Theory of Plate Tectonics
Explains how and why continents move!!!
Forces that Shape the Earth
(video clip 20 min) .

51. Earth
Plate tectonics is the theory that Earth's outer layer is made up of plates, which have moved throughout Earth's history.

52. The theory explains the how and why behind mountains, volcanoes, and earthquakes, as well as how, long ago, similar animals could have lived at the same time on what are now widely separated continents

53. Land Have you ever wondered…..
If rock can be recycled into the mantle, what rock made the continents?
If new rock is being generated at mid-ocean ridges, then what happens to the older rock?
Does the older rock get recycled? Does it become part of the neighboring continent?
Well…. The theory of Suspect Terrains can help answer your questions!!

54. Suspect Terrain
Remember …Who hypothesized that continental drift explained how continents got to their present locations?
Alfred Wegener
TheTheory of suspect terrain suggests that continents have a patchwork of terranes- each w/3 identifying characteristics.
1) Rocks and Fossils DIFFER from neighboring terrains
2) A major FAULT at the boundary
3)MAGNETIC properties don’t match neighboring terrains

55.
Continents can grow by accumulating crustal material along their edges at convergent boundaries.
Here, a terrane carried by a subducting plate is fused to the edge of a continent.
The attachment of terranes such as this contributed to continental growth along the west coast of North America.

56. Paleomagnetism
Refers to the periodic changes of the earth’s magnetic fields.
As molten rock solidifies, iron minerals in rocks align with the magnetic poles.
Changing alignments show that the poles have shifted over time.
Video Clip: Magnetic Reversal
Web link animation

57. Boundary TYPES Convergent Divergent Transform
Video: Continents Adrift (plate boundaries and characteristics)~20 min
A Science Odyssey: You Try It: Plate Tectonics
Bill Nye’s Greatest Discoveries-
Plate tectonics (14:40-19min)

58. Map Jigsaw

59. CREATE A CHART Type of Boundary Types of Crust How plates move
Type of Stress
Features
Examples

61. Animation -Boundaries, Magma, Convection

62. Divergent boundary Plates move away (or spread) from each other.
New crust is created here.
Magma forces plates apart.
Example:
Mid-Atlantic Ridge
Great Rift Valley in
East Africa

63. Geologic phenomena at divergent boundaries:
Geologic phenomena at divergent boundaries: * = unique to divergent boundaries
Iceland* (formed right on top of Mid-Atlantic Ridge)
Volcanoes
Earthquakes
Mountains
Fault-block mountains (one side is dropping lower as crust spreads)
Mid-Ocean Ridges* (Mid-Atlantic Ridge)
Rift Valleys* (Great Rift Valley, Africa)
Spreading Zones*
Crust is spread out and stretched as plates move apart.

64. Mid-Ocean Ridges
New crust created here.

65. Rift valleys (divergent)
A deep valley formed by the two plates moving away from each other.
Crust warps downward, spreads, eventually “breaks” (boundary comes to surface)
Example: Great Rift Valley in East Africa

67. Types of Convergent boundaries, continued
Continent-Continent
Two continents colliding
Pushes the crust upward to form mountains.

68. Continent-Continent Example
The Himalayas and Mount Everest—formed by Indian Plate and Eurasian Plates colliding.

70. Types of Convergent boundaries, continued
Oceanic-oceanic
Two ocean plates collide.
The older one sinks under the newer one.
Creates volcanic island arc *Not Hawaii!*

71. Oceanic-Oceanic examples
Mariana Islands (volcanic!): Formed by Philippine plate and Pacific plate
Tonga Trench in South Pacific (Pacific plate subducting under Australian plate)
Fastest moving plate: 24 cm/year!!

73. Types of Convergent boundaries
Continent-Oceanic
Ocean plate collides with a continent.
Ocean plate sinks.
Forms a trench.
Trench: also called a subduction zone, where one plate subducts under the other.

74. Continent-Oceanic, continued
Examples:
Juan de Fuca plate and North American plate
Juan de Fuca plate subducts under N.A. plate; created the Cascade Mountain Range in Northern CA, OR, and WA.
Nazca plate and South American plate
Subduction of Nazca plate formed Andes Mountains on west coast of S.A.

75. Convergent boundary Plates move toward each other and collide.
Crust is destroyed here.
Subduction: Where one plate sinks underneath another and is forced into the mantle (then melted)

76. Geologic phenomena at convergent boundaries
Volcanoes
Earthquakes
Mountains
Folded mountains (crust crumples/folds upward)
Trenches/subduction zones*
Volcanic Island Arcs (ocean-ocean boundary)*

78. Transform boundary Plates move past each other laterally.
Neither plate is destroyed.
Example:
San Andreas Fault (formed by North American and Pacific plates)

79. Geologic phenomena associated with Transform Boundaries:
Earthquakes
Fault lines
Some warping of crust

80. 3 main types of boundaries
Convergent (plates converge, or come together)
Divergent (plates diverge, or move away)
Transform (plates slide past each other)

81. Convection Ridge Push Slab Pull
Now that we have all the pieces of evidence, what drives Plate Tectonics?
Convection
Ridge Push
Slab Pull

82. Why Plates Move Convection is the driving force behind plate movement!
How It Works:
Magma in the mantle is heated by the core.
Heated magma rises toward crust.
As magma moves away from heat source, it begins to cool.
Cool magma sinks back down toward core, creating a convection cell that helps move crust.

83. Convection Heat from Hot, Molten layers in Earth
Hot, less dense material rises and cool, more dense material sinks.
Forces plates to move around

84. Convection Current

85. Slab Pull Slab pull force is a tectonic plate force due to subduction.
Convection currents cause plates to move around and subduct in certain areas. As subduction occurs, gravity pulls the slab inward towards center of earth.

86. Ridge Push
Mid-ocean ridges lie at a higher elevation than the rest of the ocean floor
Gravity causes the ridge to push on the lithosphere that lies farther from the ridge forcing it away from MOR.

87. Slab Pull and Ridge Push

88. Deformation of the Crust
The crust twists and bends under pressure and strain (stress) so it moves a lot!
Movement of Plates
Isostatic Adjustments to balance pressure between the crust and mantle
“add” to the crust (mountains, glaciers, etc) and it “sinks” farther into the mantle

89. Heavy Cream Tomatoes-canned and grape Tortellini Sour cream Cream corn Frozen veggies Spinach Eggs Ginger ale
Celery
Salad and fixings