Science Chapter 22

Front 1

What do geologists study?
Who developed the principal of uniformitarianism and what is it?
List the three main levels that the earth can be divided into.

Back 1

•Study of planet earth including it's composition and structure
•A geologic process that operates today. Also operated in the past. Developed by James Hutton. Rocks were made up of particles that come from older rocks.
1. Crust
2. Mantle
3. Core

Front 2

Which of Earth's layers corresponds to the shell of the egg?
What is the only rocky outer layer of the Earth called?
What layer is beneath the crust?
What material is the crust made up of?

Back 2

•Crust
•Crust
•Silicates
•Mantle

Front 3

Silicates often contain what type of metals?
List and describe the two different types of crust.

Back 3

•Aluminum
Calcium
Iron

1. Continental-40 km. thick. Rock that makes up continents. Consists of mainly less-dense rock such as granite.
2. Oceanic - 7km. Makes up ocean floor. Composed of dense rock like basalt. Much thinner than continental.

Front 4

List and describe the three layers of the mantle.

Back 4

1. Lithosphere - relatively cool, rigid rock, upper most mantle as well as crust.
2. Anthenosphere - Softer, weaker rock that flows slowly like taffy.
3. Mesosphere - Strongest, lower part of the mantle. Extends to upper surface of earth's core.

Front 5

List and describe the two parts of the core.
What is the relationship between the lithosphere and the mantle?

Back 5

1. Outer - high temps keep the metal liquid because of rotation. Flowing iron of outer core produces an electric current, making earth's magnetic fields.
2. Inner - very high pressure. Inner core is solid.

•Lithosphere includes crust and uppermost portion of the mantle.

Front 6

What is a mineral?
What is a rock?

Back 6

• A naturally occuring inorganic solid with a crystal structure and a characteristic chemical composition.
• A solid combination of minerals or mineral materials. Ex: Granite is made up of the rock forming minerals quartz, feldspar, mica, and hornblende.

Front 7

Why don't geologists classify coal as a mineral?
What does it mean to say that a mineral is inorganic?
Why are minerals called the building blocks of rocks?

Back 7

• Because coal was created from plant remains over the course of millions of years.
• It means that livings things did not produce them.
• Only a fractions of the nearly 4000 known minerals are common. These common minerals are called the rock forming minerals because they make up most of the earth's rocks.

Front 8

List and describe the properties by which minerals can be identified. (8)

Back 8

1. Crystal structure - atoms in a particular geometric shape or crystal structure.
2. Color: identified by a characteristic color
3. Streak: Color of minerals powder. Not always same color as mineral itself.
4. Luster: How shiny it is.
5. Density: Depends on chemical composition. Higher atomic masses have higher densities.
6. Hardness: Resistance of mineral to scratching. Scale 1-10; Diamond has 10.
7. Fracture: How a mineral breaks. Crystalline structure bonds b/w atom in crystal.
8. Cleavage: Type of fractured minerals tend to split along regular, well-defined planes, i.e, flat surfaces.

Front 9

List and describe how the three major groups of rocks form.

Back 9

1. Igneous: Molten material cools and solidifies. Found either inside earth of at the surface.
2. Sedimentary: Forms as sediment is squeezed and cemented together.
3. Metamorphic: Forms when a rock is transformed by hear, pressure, or chemical reaction. Forms under high temps. and pressures deep underground. Mineral content can be diff. from original rock b/c of crystallization.

Front 10

Intrusive igneous:
Extrusive igneous:

Back 10

• An igneous rock that forms underground from hardening magma.
• An igneous rock that forms at earth's surface.

Front 11

What does metamorphic mean?
List and describe the three main groups of Sedimentary rocks.

Back 11

• Greek for "changing form"

1. Clastic: Forms from the broken fragments of other rocks. Ex: Sandstone made from sand.
2. Chemical: Forms from the precipitation out of solution. Ex: Limestone precipitates from calcium carbonate.
3. Organic: Forms as the result of an organic process. Ex: Coral, clams, and mussels

Front 12

What kinds of rock can be a metamorphic rock?

Back 12

Any kind of rock.

Front 13

Describe the rock cycle. What causes it?

Back 13

A series of processes in which rocks continuously change from one type to another. Caused by forces w/in earth and at the surface. Many diff. paths in the rock cycle. Depending on which path you go, diff. things will be happening. (Wear away, undergo metamorphism, etc.)

Front 14

Describe the diff. forces that are involved in the rock cycle. (5)

Back 14

Melting, Cooling, Heat and pressure, Weathering and Erosion, Compacting and Cementation

Front 15

What is Plate Tectonics? Appr. what year was plate tectonics fully understood?
Continental Drift: Who is known for studying this concept?

Back 15

• The theory explaining the formation and movement of earth's plates. 1960.
• Process where the continents move slowly across the Earth's surface. Alfred Wegener.

Front 16

Explain why the fossil of plants and animals that once lived in a single region are now scattered across the globe.
List the two reason why geologists rejected the continental drift hypothesis?

Back 16

• Continental Drift

1. Unable to explain how the continents plow thru the solid rock of the sea floor.
2. Unable to give a convincing explanation of what force could move entire continents.

Front 17

What new evidence led geologists to reconsider the Continental Drift hypothesis?
What is the mid-ocean ridge?

Back 17

• Mapping the ocean floor and studying the characteristics of oceanic crust.
• A chain of underwater mountains.

Front 18

List two remarkable features of the mid-ocean ridge.
Explain the sea-floor spreading theory and which geologists is responsible.

Back 18

1. Rocks of the ocean floor are youngest near this ridge.
2. A deep valley runs along length of Atlantic's mid ocean ridge's crust.

• Process by which new oceanic crust is created at mid-ocean ridges as older crust moves away. Harry Hess.

Front 19

Where is the oldest Oceanic Crust found?
Why is the pattern of stripes the same on both sides of the ridge?

Back 19

• In rift zones
• B/c new ocean floor was being added to both sides of the mid-ocean ridge at roughly the same time.

Front 20

What causes heat to flow from Earth's hot interior toward the cooler surface?

Back 20

Earth was very hot when it formed, and some of the heat moving upward in convection currents is due to the gradual cooling of its interior.

Front 21

Explain how Earthquakes happen.

Back 21

Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little. They don't just slide smoothly; the rocks catch on each other. The rocks are still pushing against each other, but not moving. After a while, the rocks break because of all the pressure that's built up. When the rocks break, the earthquake occurs. During the earthquake and afterward, the plates or blocks of rock start moving, and they continue to move until they get stuck again.

Front 22

What is an Earthquake?
The energy released during an earthquake is carried by vibrations called what?

Back 22

• A movement of Earth's lithosphere that occurs when rocks in the lithosphere suddenly shift, releasing stored energy.
• Seismic Waves

Front 23

Focus:
Epicenter

Back 23

• The spot underground where the rock breaks.
• The spot right above the focus (on top of the ground).

Front 24

What is stress when you are talking about Earthquakes?
What produces faults and folds?

Back 24

• A force that squeezed rocks together, stretches or pulls them apart, or pushes them in diff. directions.
• As tectonic plates move, they cause stress in the crust resulting in faults and folds.

Front 25

Describe what a fault and a fold is. Where do they occur?
What provides the energy that creates an earthquake?

Back 25

1. Fault: A break in a mass of rock along which movement occurs. Along plate boundaries.
2. Fold: A bend in layers of rock. Forms when rocks are squeezed together.
• The buildup of stress along the fault.

Front 26

List and describe the types of seismic waves.

Back 26

1. P waves: wave that can travel through gases (such as sounds), elastic solids and liquids, including the Earth. Fastest type. Stands for Primary Wave.
2. S waves:they move through the body of an object, unlike surface waves. Second wave, because it moves slower than primary through rock.
3. Surface Waves: they move the surface of the earth up and down. This generally causes the worst damage because the wave motion rocks the foundations of manmade structures. Comes at end of Earthquake. Slowest.

Front 27

What instrument do geologists use to measure and record seismic waves?
Where are most Earthquakes concentrated?

Back 27

• Seismographs
• Along plate boundaries, where many faults are found.