Chapter 1: Earth as a System

Question 1

Principles of Actualism

Answer 1

fundamental physical & chemical principles observed operating today have operated throughout Earth’s history

Question 2

Catastrophism

Answer 2

global floods caused by supernatural forces formed most of the rocks visible at Earth’s surface.
- Attribute all layers of rocks to series of catastrophes

Question 3

Principles of Uniformitarianism

Answer 3

present is key to the past

• Somewhat rigid view of Earth’s eternal processes
  § Ex: no events played important geological role - denied by impact of asteroid
  § Ex: all geological changes are gradual - denied by numerous agents which operated with suddenness
  § Ex: all kinds of rocks have never basically changed - denied by new kinds of rocks & organism appear, mammals existed in only 5 percent of planet’s history.

Question 4

Mineral

Answer 4

Naturally occurring
Inorganic 
Solid
Element/ Compound
Particular chemical composition
Characteristic mineral structure/ Crystal lattice

Question 5

Rock

Answer 5

consist of interlocking or bonded grains of matter - typically composed of single minerals

Question 6

Igneous

Answer 6

cooling of molten materials

Question 7

Sedimentary

Answer 7

bonding of loose sediments by compression after burial or precipitation of mineral cement - result of lithification of sediment

Question 8

Metamorphic

Answer 8

alteration of rocks within Earth under conditions of high temp & pressure

Question 9

Steno’s Law: Principle of Superposition

Answer 9

in an undisturbed sequence of data - oldest at bottom & successively higher strata are progressively younger

Question 10

Steno’s Law: Principle of Original Horizontality

Answer 10

all strata are horizontal when they form

Question 11

Steno’s Law: Principle of Lateral Continuity

Answer 11

strata originally are unbroken flat expanses, original continuity can be broken by erosions (ex: when river cuts downward)

Question 12

Principle of Intrusive Relationship

Answer 12

intrusive igneous rock is always younger than the rock that it invades

Question 13

Principle of Inclusion

Answer 13

when fragments of one body of rock are found within a second body, the 2nd is always younger than the 1st.

Question 14

Unconformity

Answer 14

irregular surface between two bodies of rock

Question 15

Angular Unconformity

Answer 15

a group of rocks has been tilted & eroded & younger rocks are deposited on top

Question 16

Disconformity

Answer 16

the irregular surface between the upper & lower rock bodies reveals a past episode of erosion

Question 17

Nonconformity

Answer 17

a bedded rocks rest on an eroded surface of crystalline (igneous/ metamorphic) rocks

Question 18

Fossil

Answer 18

tangible remains/signs of ancient organism

Question 19

Geological Time Scale

Answer 19

Divides Earth’s history into formal units (see side pic)
Divides by the levels in which geologist discover abundant fossils
Eons, Eras, Periods, Epochs
Geological systems
□ Unique group of fossils
□ Nature of rock

Question 20

Core

Answer 20

Solid, spherical inner portion

Liquid outer portion - consist mostly of iron

Question 21

Mantle

Answer 21

§ Thick envelop around core
§ Complex body of less dense rocky materials
§ Made up most of Earth’s volume

Question 22

Crust

Answer 22

still less dense (than mantle & core) rock material

Question 23

Moho - Mohoroviěié discontinuity

Answer 23

passage between crust to mantle where waves increase in velocity abruptly

Question 24

Lithosphere

Answer 24

crust & upper mantle

Question 25

Asthenosphere

Answer 25

“low-velocity zone”, composed of partially molten rock, slush like, solid particles with liquid occupying in between, 10% thickness of mantle

Question 26

Basics of Plate Tectonic

Answer 26

the movement of lithospheric plates; driven by convection (process by which material that is heated deep within the asthenosphere rises to displace cooler, less dense material near surface)

Question 27

Type of boundary: Spreading Zones

Answer 27

plates move apart, mafic material of relatively low density rise from ultramafic asthenosphere and become new lithosphere, lithosphere slide laterally away
□ Ex: Mid-ocean ridge (Mid-Atlantic)

Question 28

Type of boundary: Subduction Zones

Answer 28

plates move back down the asthenosphere along deep-sea trenches

Question 29

Type of boundary: Transform Faults

Answer 29

plates slide along each other; faults offset mid-ocean ridges throughout their length

Question 30

Water Cycle

Answer 30

see OneNote

Question 31

Darwin’s Theory of Evolution

Answer 31

particular kinds of animals & plants gave rise to other kinds
- cyclical but progressional, constantly giving rise to new kinds of organisms

Question 32

Directional changes: Physical

Answer 32

cooling of planet’s interior - weakened furnace, plate tectonic weakened, less subduction & spreading zones

Question 33

Directional changes: Chemical

Answer 33

shifts of oxygen concentration

Question 34

Ecosystem

Answer 34

an environment together with the group of organisms that lives within it.
- Environmental change influenced ecosystems. Study of ancient ecosystems let geologists know how to confront future environmental changes.