Earth Science Unit 5

Front 1

Relative Dating

Back 1

Involves placing geologic events in sequential order as determined from their position in the geologic record

(Does not tell us how long ago a particular event occurred, only that one happened before the other)

Front 2

Absolute Dating

Back 2

Expressed in Years Before Present (YBP)

Radiometric Dating

Most common method of obtaining absolute ages

Calculated from natural rates of decay (isotopes)

Front 3

Radiometric Dating

Back 3

Most common method of obtaining Absolute Dating

Calculated from Natural Rates of Decay

Front 4

What did the discovery of radioactivity allow?

Back 4

Allowed Absolute Ages to be applied to the Geographic Time Scale

Front 5

What is the Geologic Time scale made of?

Back 5

Eons, Eras, Periods, Epochs

Front 6

Nicolas Steno

Back 6

Principles of Superposition

Principle of Original Horizontality

Principle of Lateral Continuity

Front 7

Principles of Superposition

Back 7

In an undisturbed succession of sedimentary rocks, the rocks on the bottom are older, and the rocks on the top are younger

Front 8

Principle of Original Horizontality

Back 8

Sediment is originally deposited in Horizontal Layers

Therefore, a sequence of sedimentary rock layers that is steeply inclined must have been tilted after deposition and lithification

Front 9

Principle of Lateral Continuity

Back 9

Sediment extends laterally in all directions until it thins and pinches out or terminates against the edges of the depositional basin

Front 10

Principle of Cross-Cutting Relationships

Back 10

An igneous intrusion or a fault must be younger than the rocks in intrudes or displaces

Front 11

James Hutton

Back 11

Principle of Cross-Cutting Relatiionships

Front 12

Principle of Inclusions

Back 12

Contained with another rock

Rock containing the inclusion is younger

Front 13

Principle of Fossil Succession

Back 13

Fossils occur in a definite, invariable sequence in the geologic record;

Front 14

Radioactivity

Back 14

Spontaneous decay of an atom's nucleus to a more stable form

Front 15

Isotope

Back 15

a

Front 16

Half Life

Back 16

The time it takes for 1/2 of the original parent isotope to decay to a more stable daughter isotope

Front 17

Sources of Uncertainty

Back 17

A Closed System is needed for an accurate date

Leakage of Isotope

Metamorphism

Front 18

What are the different types of leakages?

Back 18

Daughter Escape - Date will be too young

Parent Escape - Date will be too old

Front 19

Metamorphism

Back 19

Date obtained would be the time of metamorphism

Front 20

Correlation of Rock Layers

Back 20

Matching rocks of similar age I. Different regions often relies upon fossils

Front 21

Tracks

Back 21

A

Front 22

Burrows

Back 22

A

Front 23

Coprolites

Back 23

Fossil dung and stomach contents

Front 24

Gastroliths

Back 24

Stomach stones used to grind food by some extinct reptiles

Front 25

Principle of Fossil Succession

Back 25

Fossils succeed one another in a definite and determinable order

William Smith

Front 26

Petrified

Back 26

Cavities and pores filled with mineral matter

Front 27

Replacement

Back 27

Cell material replaced with mineral matter

Front 28

Mold

Back 28

Shell or other structure buried then dissolved away. The outer shell. Hollow on the inside

Front 29

Cast

Back 29

Hollow space of a mold is filled with mineral matter

Front 30

Carbonization

Back 30

Organic matter becomes residue of carbon

Front 31

Impression

Back 31

Replica of fossil's surface preserved in fine grained sediment

Front 32

Preservation in Amber

Back 32

Hardened resin of ancient trees surround an organism

Front 33

Direct Evidence

Back 33

A

Front 34

Indirect Evidence

Back 34

Tracks

Burrows

Coprolites

Gastrolihs

Front 35

Correlation of Rock Layers

Back 35

Matching rocks of similar age I. Different regions often relies upon fossils

Front 36

Tracks

Back 36

A

Front 37

Burrows

Back 37

A

Front 38

Coprolites

Back 38

Fossil dung and stomach contents

Front 39

Gastroliths

Back 39

Stomach stones used to grind food by some extinct reptiles

Front 40

Principle of Fossil Succession

Back 40

Fossils succeed one another in a definite and determinable order

William Smith

Front 41

Petrified

Back 41

Cavities and pores filled with mineral matter

Front 42

Replacement

Back 42

Cell material replaced with mineral matter

Front 43

Mold

Back 43

Shell or other structure buried then dissolved away. The outer shell. Hollow on the inside

Front 44

Cast

Back 44

Hollow space of a mold is filled with mineral matter

Front 45

Carbonization

Back 45

Organic matter becomes residue of carbon

Front 46

Impression

Back 46

Replica of fossil's surface preserved in fine grained sediment

Front 47

Preservation in Amber

Back 47

Hardened resin of ancient trees surround an organism

Front 48

Direct Evidence

Back 48

A

Front 49

Indirect Evidence

Back 49

Tracks

Burrows

Coprolites

Gastrolihs