Geology 101 Exam 1

Front 1

Big Bang

Back 1

- All mass and energy in a “Single Point” and explosion/expansion ~13.7 Ga
- Atoms and molecules coalesce in gaseous nebulae

Front 2

Expanding Universe
How do we know?

Back 2

- Light from galaxies was seen to be “red shifted"
- Hubble recognized the red shift as a Doppler Effect

RED LIGHT (low frequency) away
BLUE LIGHT (high frequency) towards

Front 3

Hypothesis

Back 3

a reasonable idea that has the possibility of being correct, but has not been proven

Front 4

Theory

Back 4

scientific idea supported by an abundance of evidence that has passed many tests and failed none

Front 5

Big Theories of Geology (2)

Back 5

Plate Tectonics – theory that the outer layers of the Earth consists of separate plates that move w/ respect to one another

Geologic Time – span of time since the formation of the Earth

Front 6

Alfred Wegener

Back 6

Continental Drift Hypothesis - Idea that continents are mobile; once a supercontinent Pangaea (Pangea)

Front 7

Evidences for Continental Drift (5)

PGFR

Back 7

1. “Fit” of continents
2. Location of glaciers (GLACIATION)
3. Location/distribution of fossils
4. Rock types and structural similarities
5. Paleoclimates preserved in rocks

Front 8

(2) Glaciation

Back 8

- Striations on rock cut by glacial movement indicate
direction of movement
- Glacial tills present

Front 9

(3) Fossil Distribution

Back 9

Identical fossils
Glossopteris- A subpolar plant with heavy seeds
Plant evidenced in southern hemisphere of Pangea (Gondwanaland)

Front 10

(4) Rock types and structural similarities

Back 10

Matching of Rock Types
- Geologic structures.
- Rock types.
- Rock ages
- Mountain belts: The Appalachians & The Caledonides

Front 11

(5) Paleoclimates preserved in rocks

Back 11

Minerals and rocks form in certain climates.
Reconstruction puts mineral in the right place for formation.
EX: Russia has coal deposits

Front 12

Criticisms of Continental Drift

Back 12

Why wasn’t the continental drift hypothesis accepted?
– There were no mechanisms for moving continents.
– When Wegener died, the debate did too

Front 13

Continental Drift new evidence

Back 13

This was provided by:
- Paleomagnetism
- Age of the ocean floor
- Volcano distribution
- Earthquake distribution
- Hot spots

Front 14

Sea-Floor Spreading

Back 14

Process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge

Max ocean Age= 108 mya

Front 15

What are the dominant elements?
(1) Crust
(2) Whole Earth

Back 15

(1) Crust: Oxygen – 46% Silicon – 28%

(2) Whole Earth: Iron - 35% Oxygen – 30%

Early settling of core

Front 16

Compositional Differences

Back 16

Front 17

Heat of the Earth (3)

Back 17

1. Particle collision
2. Gravity settling,
3. Radioactive decay*

Front 18

P-Wave Travel

Back 18

P waves travel through all materials

Front 19

S-Wave Travel

Back 19

S waves can’t pass through liquids

Front 20

Earth is dynamic, Mars is static. What other differences?

Back 20

(1) core has been lost
(2) Remnants of magnetic field

Mars biggest volcano is Olympus

Front 21

Layers:
(1) Crust
(2) Lithosphere
(3) Mantle
(4) Outer Core
(5) Inner Core

Back 21

(1) Crust: Continental and Oceanic
(2) Lithosphere: Includes crust and upper mantle
(3) Mantle – solid to plastic
(4) Outer Core - liquid
(5) Inner Core - solid

Front 22

Earthquakes

Back 22

Found to be concentrated at the areas of
- spreading (shallow)
- convergent (deeper)
- transform “plate” boundaries
-some occur within plates (intraplate)

Front 23

Hot spots

Back 23

- Not related to plate margins
- Source of magma is believed to be deep within the mantle at fixed locations

Front 24

Plate Tectonics
Mechanisms for driving plates

Back 24

Slab Pull