Geol-111 Geologic Time

Front 1

What 2 very important things occured during the Permean period?

Back 1

1) The supercontinent Pangea formed (created the Appalachian Mts.)
2) Created the greatest mass extinction of organisms on Earth.

Front 2

Putting rock units in sequence from oldest to youngest and determining an actual age:

Back 2

Relative age

Front 3

What is the largest chunk of geologic time?

Back 3

Precambrian

Front 4

How old is the Earth?

Back 4

4.6 billion years

Front 5

"Old life":

Back 5

Paleozoic

Front 6

Linking together rock layers across long distances:

Back 6

Correlation

Front 7

Recent epoch:

Back 7

Holocene

Front 8

Which unit of geologic time do we know the least about?

Back 8

Precambrian b/c there us an abscence of fossil evidence since most of the rocks are igneous/metamorphic and don't contain fossils.

Front 9

A surface of erosion or nondeposition that represents a particular amount of missing time:

Back 9

Unconformity

Front 10

During what period were the Rocky Mts. formed?

Back 10

Cretaceous

Front 11

What helps us correlate rock layers better than anything?

Back 11

Fossils

Front 12

What type of unconformity is the most difficult to identify and why?

Back 12

Disconformity - difficult b/c all of the rock layers are sedimentary.

Front 13

The actual age of the rock layer:

Back 13

Absolute age

Front 14

What index fossil only lived during the cretaceous period?

Back 14

Inoceramus (clam found in TX)

Front 15

During what period did dinosaurs become extinct?

Back 15

Cretaceous

Front 16

What was the very first angular unconformity ever identified?

Back 16

Siccar Point, Scotland

Front 17

"New life":

Back 17

Cenozoic

Front 18

What are the best fossils for correlating rock layers?

Back 18

Index fossils

Front 19

What is the half-life of Uranium 238?

Back 19

4.5 billion years

Front 20

What is the oldest period of the Paleozoic era?

Back 20

Cambrian

Front 21

An unconformity w/ either igneous or metamorphic rock below the unconformity and sedimentary rock above the unconformity:

Back 21

Nonconformity

Front 22

When was radioactivity discovered? What did this discovery lead to?

Back 22

1905 - led to the ability to determine absolute age.

Front 23

When was the Ice Age?

Back 23

During the Pleistocene epoch

Front 24

The amount of time it takes for 1/2 of parent isotopes to decay into daughter isotopes:

Back 24

Half-life

Front 25

An unconformity between parallel, sedimentary rock layers:

Back 25

Disconformity

Front 26

During what period did birds first form?

Back 26

Jurassic

Front 27

Technique used to determine the absolute age of a rock layer:

Back 27

Radioactive dating

Front 28

What is the parent isotope of Lead 206?

Back 28

Uranium 238

Front 29

What type of unconformity is at the base of the Grand Canyon?

Back 29

Nonconformity

Front 30

During what period did Pangea begin to break up?

Back 30

Triassic

Front 31

What is the daughter isotope of uranium 238?

Back 31

Lead 206

Front 32

What is the parent isotope of Argon 40?

Back 32

Potassium 40

Front 33

"Middle life":

Back 33

Mesozoic

Front 34

States that the present is the key to the past:

Back 34

Uniformitarianism

Front 35

During what period did the first fish appear?

Back 35

Ordovician

Front 36

When were the oldest rocks on the surface of Louisiana created?

Back 36

During the Paleocene epoch

Front 37

Unconformity w/ all sedimentary rocks, but the rocks below the unconformity are tilted @ a different angle than the rocks above the unconformity:

Back 37

Angular unconformity

Front 38

What is the half-life of Potassium 40?

Back 38

1.3 billion years

Front 39

What time units are eras subdivided into?

Back 39

Periods

Front 40

When did the Himalayas form?

Back 40

Eocene epoch

Front 41

During what period did the first anphibians appear?

Back 41

Mississippian

Front 42

List all 4 eras from the oldest to the youngest:

Back 42

Precambrian
Paleozoic
Mesozoic
Cenozoic

Front 43

What is the half-life of Carbon 14?

Back 43

5,730 years

Front 44

When was the earliest fossil recorded of life?

Back 44

Precambrian era

Front 45

During what period did the first land plants appear?

Back 45

Silurian

Front 46

What is the daughter isotope of Potassium 40?

Back 46

Argon 40

Front 47

During what period did the first dinosaurs appear?

Back 47

Triassic

Front 48

When were the earliest humans around?

Back 48

During the Pleistocene (Ice Age) epoch

Front 49

What are the 3 characteristics of index fossils?

Back 49

1) Easy to identify.
2) Lived for a relatively short period of geologic time.
3) Lived for only one unit of geologic time (MOST IMPORTANT).

Front 50

An element with different numbers of neutrons:

Back 50

Isotope

Front 51

During what period did the first reptiles appear?

Back 51

Pennsylvanian

Front 52

What is the daughter isotope of Carbon 14?

Back 52

Nitrogen 14

Front 53

During what period did the first mammals appear?

Back 53

Triassic

Front 54

Why are the Mississippian and Pennsylvanian periods so important to LA?

Back 54

Because there was a hot, swampy environment which produced COAL.

Front 55

When did the earliest shelled animals first appear?

Back 55

Precambrian era

Front 56

How many different species of invertebrate and vertebrate marine organisms have been identified based on fossils from the Cane River site?

Back 56

150

Front 57

The vast majority of surface exposures in Louisiana are from what periods?

Back 57

Tertiary and Quaternary in age (less than 65 million years old)

Front 58

What do the various fossils at the Cane River Site indicate about its paleoenvironment?

Back 58

It was probably a shallow ocean with tropical to
subtropical conditions.

Front 59

Exposed strata or sediments where fossils may be recovered:

Back 59

Fossiliferous outcrops

Front 60

How old are the marine fossils from the Cane River Site?

Back 60

46 million years old

Front 61

Stable isotope:

Back 61

Daughter isotope

Front 62

If a stratigraphic sequence is missing a layer that should be present, then it is said to have:

Back 62

An unconformity

Front 63

What were the most abundant invertebrate fossils found at the Cane River site?

Back 63

Microscopic forms:
-foraminifera
-ostracodes

Megascopic forms:
-oysters
-corals

Front 64

The ancient water depth of the Cane River site was probably around ____.

Back 64

20-50 meters

Front 65

Most of the rocks exposed at the surface of Earth are ____.

Back 65

Sedimentary

Front 66

Analysis of radioactive isotopes indicates that a rock contains 150 parent isotopes and 1050 daughter isotopes. If the half life of the isotope is 50 million years, how old is the rock?

Back 66

150 million years

Front 67

A radioactive isotope has a half life of 20 million years. If the isotope has decayed four half lives, how old is the rock?

Back 67

80 million years

Front 68

A rock contains 1000 parent isotopes. After it has decayed 3 half lives, what is the ratio of parent:daughter isotopes?

Back 68

125 parents:875 daughters