Earth's History

Question 1

Uniformitarianism

Answer 1

The principle that most of the goelogic events of the past are similar to processes that we can observe in the present

Question 2

Law of Superposition

Answer 2

The principle that the lowest layers in a sequence of rock strata must have been deposited before the layers above, unless the rocks have been turned upside down

Question 3

Outcrop

Answer 3

bedrock that is exposed at the surface because it is not covered by soil

Question 4

Orogeny

Answer 4

the process of mountiain building

Question 5

Extrusion

Answer 5

Molten, liquid rock (lava) flowing out onto the surface of the earth. (fine grained igneous rock)

Question 6

Intrusion

Answer 6

molten, liquid rock (magma) being pushed into cracks within the earth. (coarse grained igneous rock)

Question 7

Lava

Answer 7

molten rock at the surface of the earth

Question 8

folded strata

Answer 8

layers of rock that have been bent by forces within the Earth

Question 9

Fault

Answer 9

a break in the rock of the Earth’s crust along which there has been displacement

Question 10

Uplift

Answer 10

The rising of the Earth’s crust from forces within the Earth, generally related to motions of the tectonic plates

Question 11

Joint

Answer 11

a crack in a rock produced by shrinking or uneven pressure. (no displacement happens).

Question 12

Fossil

Answer 12

Any preserved remains or traces of life

Question 13

Species

Answer 13

a group of living organisms with similar characteristics, a common name, can reproduce

Question 14

Correlation

Answer 14

A matchup of rock layers in different locations by age or rock types

Question 15

Index Fossil

Answer 15

A fossil that can be found over a large geographic area but existed for a brief period of geologic time

Question 16

Organic Evolution

Answer 16

The principle that living things have changed in form through the history of the Earth from a few simple organisms to a great diversity of organisms

Question 17

Dendritec

Answer 17

a pattern resembling tree branches

Question 18

Unconformity

Answer 18

a gap in the geologic record caused by the erosion of sediments or rock before they are protected by layers above

Question 19

Absolute Age

Answer 19

The age of a rock unit, a fossil, or an event expressed in units of time, such as years

Question 20

Relative Age

Answer 20

Age expressed as before or after other events without specifying the age in units of measure. a comparative age

Question 21

Radioactivity

Answer 21

The emission of energy rays or nuclear particles from the breakdown of an unstable isotope

Question 22

Radiative Balance

Answer 22

Equilibrium between absorbed radiant energy and radiant energy given off

Question 23

Isotope

Answer 23

a form of an element with more or fewer neutrons than other forms of the same element

Question 24

Decay product

Answer 24

The element produced by the decay of a radioactive isotope

Question 25

Half-Life

Answer 25

The time required for half of a radioactive element’s atoms in a sample to change to the decay product

Question 26

Decay-Product Ratio

Answer 26

The ratio between the mass of a radioactive element and its decay product

Question 27

Carbon 14

Answer 27

a radioactive form of the element carbon that has been used to find the absolute age of recent fossils and geologic events

Question 28

Reversed Magnetic Polarity

Answer 28

An igneous rock that was formed at a time in the geologic past when the north and south magnetic poles of the Earth had opposite polarity that they have at the present

Question 29

Geologic Time Scale

Answer 29

Division of the history of the Earth originally based upon observations of fossil evidence

Question 30

Era

Answer 30

a large division of geologic time

Question 31

Period

Answer 31

In geologic time, a subdivision of an era

Question 32

Event

Answer 32

A change or series of changes in the Earth’s environment

Question 33

Time

Answer 33

a measurable period in which an event or process occurs

Question 34

Pangaea

Answer 34

The ancient supercontinent that broke apart millions of years ago to form the present continents

Question 35

Ice Age

Answer 35

A long period of Earth’s history when ice sheets cover large areas of the continents.