Chapter 4 Earth & the Environment

Question 1

What 2 primary sources of energy drive our “Earth System?”

Answer 1

1. Solar radiation emitted from the sun.
2. Heat contained within our planet

Question 2

Rocks undergo deformation when acted upon some type of outside _____________

Answer 2

Force or Stress

Question 3

Strain usually involves some change in____________ or _________________.

Answer 3

Shape or volume

Question 4

What is the point where rocks will no longer behave elastically and deformation becomes permanent?

Answer 4

Elastic Limit

Question 5

Brittle

Answer 5

When rocks break by fracturing (upper crust)

Question 6

Ductile

Answer 6

When rocks deform by flowing and folding (lower crust and upper mantle)

Question 7

What is the difference in stress and strain in rock deformation?

Answer 7

Stress is caused by a force acting on a rock.
Strain is the result of deformation.

Question 8

What are 3 types of stress?

Answer 8

1. Compression
   2.Tension
   3.Shear

Question 9

What force occurs when an object is squeezed?

Answer 9

Compression

Question 10

What force occurs when an object is pulled apart?

Answer 10

Tension

Question 11

What force develops when surfaces slide past one another?

Answer 11

Shear

Question 12

What are earth’s 3 compositional layers and how thick are they?

Answer 12

1. Crust: 5-75 km thick
2. Mantle: extends from base of crust to ~2900 km depth
3. Core: extends from base of mantle to 6371 km depth

Question 13

What is earth’s crust mostly contain?

Answer 13

Light silicate-rich rocks

Question 14

Oceanic crust is thinner and dense than _________________ crust.

Answer 14

continental

Question 15

The mantle made up mostly of what?

Answer 15

Ultramafic silicate-rich rocks

Question 16

The earth’s core is composed almost entirely of __________________.

Answer 16

Iron

Question 17

What are earth’s 5 mechanical layers?

Answer 17

1. Lithosphere
2. Athenosphere
3. Mesosphere
4. Outer Core
5. Inner Core

Question 18

Which mechanical layer of Earth is the outmost rigid layer that is composed of crust + uppermost mantle?

Answer 18

Lithosphere

Question 19

Which mechanical layer of Earth extends from base of lithosphere to ~660km depth?

Answer 19

Athenosphere

Question 20

Does the athenosphere behave as a soft solid or rigid?

Answer 20

Soft solid

Question 21

Is the athenosphere ductile or brittle deformation?

Answer 21

Ductile

Question 22

The rigid mesosphere is the remainder of the :
A. Crust
B. Mantle
C. Dr. K’s shoes

Answer 22

B.. Mantle

Question 23

Which mechanical layer of earth is liquid iron that is flowing?

Answer 23

Outer Core

Question 24

The inner core of the earth is solid _____________.

Answer 24

Iron

Question 25

In Wegener’s theory of Continental Drift, he hypothesized Pangaea. What is Pangaea?

Answer 25

A supercontinent. All the continents were together, as in one big continent.

Question 26

What is the theory that land masses slowly drift?

Answer 26

Theory of Continental Drift

Question 27

What are 5 observations Wegener made in the Theory of Continental Drift?

Answer 27

1. Continents appear to have fit together in the past.
2. Evidence of glaciers found on 5 continents.
3. Interpreted ancient environments in wrong present day places
4. Identical fossils found on widely separate land masses.
5. Distinctive rock assemblages and mountain belts match across the Atlantic

Question 28

Even though Wegener had strong lines of evidence, why was his ideas ignored?

Answer 28

He could not explain why or how continents moved.

Question 29

What is a submarine mountain range in found in all oceans?

Answer 29

Mid-ocean ridge

Question 30

Deep, narrow depressions that parallel coastlines and are found where you also find volcanoes

Answer 30

Ocean trenches

Question 31

4 observations of sea floor spreading

Answer 31

1. Sediment thickens away from ridges
2. Earthquakes at MOR indicate cracking
3. New ocean floor forming at MOR
4. Earthquakes at trenches indicate collisions and bending

Question 32

What are individual slabs of the brittle lithosphere that move over the relatively weak asthenosphere?

Answer 32

Plate Tectonics

Question 33

What are the 3 types of plate boundaries?

Answer 33

1.Divergent
2. Convergent
3. Transform

Question 34

Name that plate boundary!
1. Plates move apart: tensions stress
2. Significant volcanism and many small earthquakes
3. New lithosphere is created at these boundaries

Answer 34

Divergent plate boundary

Question 35

What kind of divergent boundary is defined by:
1. oceanic plates moving apart at MOR
2. rising asthenoshpere melts, forming mafic magma
3. Magma solidifies into new oceanic crust

Answer 35

Oceanic Divergent Boundary

Question 36

Name 3 things that happens at Convergent Plate Boundaries.

Answer 36

1. compressional forces
2. Subduction
3. Earths greatest earthquakes

Question 37

To have subduction, one plate MUST be_______________.

Answer 37

Oceanic crust

Question 38

3 types of convergent boundaries:

Answer 38

1. Ocean-ocean convergence
2. Ocean-continent convergence
3. Continent-continent convergence

Question 39

Plate Boundary where tectonic plates slide past each other: shear stresses

Answer 39

Transform Plate Boundary

Question 40

Plume of deep mantle material independent of plates

Answer 40

Hotspots

Question 41

There are 2 primary forces that drive plate motions (Driving mechanisms). What are they?

Answer 41

1. Ridge-push
2. Slab-pull

Question 42

Both driving mechanism forces, ridge-push and slab-pull, are driven by ____________________ in the upper mantle.

Answer 42

convection