Ch.1: The Earth in Context

Question 1

Geology

Answer 1

The study of the earth

Focuses on materials the earth is made out of: rocks, minerals, mountains

Question 2

Layers of the earth

Answer 2

Crust (oceanic thinner and continental thicker, boyant)
Moho = base of the crust
Upper mantle
Lower mantle
Liquid molten outer core
Solid inner core

Question 3

Sialic vs. Mafic

Answer 3

Continental crust = sialic (Si + Al) granite

Oceanic crust = mafic (Mg + Fe) basalt

Question 4

Lithosphere

Answer 4

Strong outer shell, about 100 km thick; plates are made of lithosphere
Crust + upper mantle

Question 5

Asthenosphere

Answer 5

weak, zone of partial melting; flow in asthenosphere moves the over-riding plates
Upper mantle

Question 6

Pre-Socrates

Answer 6

Believed earth was flat and in the center (geocentric)

Question 7

Aristotle 350 BCE

Answer 7

Spherical earth surrounded by concentric spheres
Aristotle on geologic time:
“But the whole vital process of the earth takes place
so gradually and in periods of time which are so
immense compared with the length of our life, that
these changes are not observed, and before their
course can be recorded from beginning to end whole
nations perish and are destroyed.”

Question 8

Eratosthanes 200 BCE

Answer 8

Determined earth’s size using oblekes
On summer solstice at noon in Alexandria, he measured
the length of an obelisk’s shadow.
At the same time, the sun’s rays cast no shadow down
a vertical pit in Syene, therefore the rays were vertical.
He calculated the sun’s angle from its zenith as 7.2°, or 1/50th of the earth’s circumference.

Question 9

Copernicus

Answer 9

Published evidence for heliocentricity 15th centruty europe

Question 10

Galileo

Answer 10

observations (phases of Venus,

moons orbiting Jupiter) confirmed heliocentrism.

Question 11

Hutton

Answer 11

Wrote Theory of the Earth:
• Earth is very old, having " ...no vestige
of a beginning, no prospect of an end"
• Formulated idea of Uniformitarianism:
"The present is the key to the past"
18th c Scottish

Question 12

Lynell

Answer 12

19th C.
Principles of Geology
Found fossils in rocks
“Sea has been changed into land. Marine shells lie far distant from the deep.”

Question 13

Big Bang

Answer 13

13.8 billion years ago
This theory proposes that all matter and energy in the Universe started out as a single infinitesimally small point that exploded and has been expanding ever since

Question 14

Nebular Theory

Answer 14

~4.6 billion years ago from older stars.
The nebula condensed into a protoplanetary disk.
The center of the nebular disk glowed with heat and ignited into nuclear fusion.
big bang-> disk -> stars -> planets->differentiation->moon

Question 15

Planetary Acretion Model

Answer 15

The dust in the rings accreted or coalesced to form planetesimals, which gradually combined into planets.

Question 16

Earth and moon formation

Answer 16

1) Nebula becomes a disk
2) Birth of the sun
3) Planetesimals coalesce
4) Differentiation
5) Moon formation
6) Atmosphere evolves
After earth’s differentiation, a Mars-sized planetoid collided with us, blasting out a large part of the mantle.
Debris from the collision coalesced to form the Moon

Question 17

Differentiation of the Earth’s Interior

Answer 17

Early on, the Earth was fairly homogeneous inside.
When the temperature got hot enough, iron began to melt. The iron accumulated at the center of the planet to form a metallic core.

Question 18

Composition of the earth as a whole

Answer 18

90% percent of Earth is comprised of 4 elements
– Iron (Fe) – 35%
– Oxygen (O) – 30%
– Silicon (Si) – 15%
– Magnesium (Mg) – 10%
• The remaining elements
– Form 10% of Earth
MAFIC ( rich in Magnesium and Iron)

Question 19

Composition of Earth’s crust

Answer 19

Oxygen 46%
Silicon 28%
Aluminum 11%
Iron 6%
SIALIC (rich in Silicon and Aluminum)

Question 20

Henry Hess

Answer 20

Sea floor spreading

Question 21

Robert Diatz

Answer 21

Subduction

Question 22

J. Tuzo Wilson

Answer 22

Hot spot volcano track

Question 23

Wadarti and Benioff

Answer 23

Inclined plane of earthquakes within subduction zone

Question 24

Tanya Atwater

Answer 24

San Andreas Fault