Units 28-29

Question 1

What is deep time?

Answer 1

Time that stretches back a LOOOONNNG time ago. billions of years

Question 2

Uniformatarianism

Answer 2

The idea that the laws of nature do not change with time.

aka. Time symmetry

Question 3

Occam’s razor

Answer 3

If two or more explanations exist for the same physical phenomenon, we choose the simplest that satisfies all the observations.

Question 4

Relative time

Answer 4

The determination of the sequence in which events occurred, relative to each other.
Think “timeline” game

Question 5

Absolute time

Answer 5

A numeric or quantitative measure of time

Question 6

What is another name for absolute time?

Answer 6

Numeric or quantitative time

Question 7

What are the 5 principles of relative dating that we will talk about in class?

Answer 7

1. Original horizontality
2. Superposition
3. Inclusions
4. Cross-cutting relationships
5. Faunal succession

Question 8

Original horizontality

Answer 8

Sedimentary rocks are deposited in horizontal layers. They are FORMED horizontally

So we can analyze ancient sediment to determine age

Question 9

Principle of superposition

Answer 9

In a stack of sedimentary layers (split by different composition), the oldest layer will be on the bottom and the youngest on the top

Question 10

Principle of inclusions

Answer 10

Inclusions within the rock.

Solid materials (like pebbles) enclosed within another solid are OLDER than the rock that encloses them.

Question 11

Inclusions

Answer 11

Rock, fragment of rock, or fossil enclosed within another rock.

Question 12

Ammonites

Answer 12

The name given to the fossil shell remains of animals that lived in the oceans millions of years ago, but are now extinct.

Squidlike (nautilus stuff)

Question 13

Fault

Answer 13

A break in earth’s lithosphere where rocks on one side of the break have slipped past the rocks on the other side.

Question 14

True or False: Faults are CREATED by earthquakes.

Answer 14

True

Question 15

Principle of cross-cutting relationships

Answer 15

Rocks are OLDER THAN the features (like faults) or rocks that cross-cut them.

Question 16

Trilobites

Answer 16

A common animal that lived in earth’s oceans during the paleozoic era. Horseshoe crab, pillbug features

Question 17

Principle of faunal succession

Answer 17

Within stacks of sedimentary rocks, there is a pattern of change in the types of fossils the layers contain.

The fossils can therefore help us determine the relative age of different layers.

Question 18

True or False: Rock layers often have distinct groups of fossils.

Answer 18

True

Question 19

Unconformity

Answer 19

A break or gap in the geologic record

Question 20

What kinds of unconformities are found in our geologic history?

Answer 20

Sedimentation stopped in some areas, sedimentary layers formed many feet below the surface of the ocean and were then lifted high above sea level to be eroded away, natural events destroyed layers, etc.

Question 21

Parent and daughter isotopes

Answer 21

The result of radioactive decay, in which one element decays to form another element.

The starting element = parent
New element formed from decay process = daughter

Question 22

Why do geologists use two or more isotopic systems to date rocks?

Answer 22

For greater accuracy, to verify results

Question 23

Where does carbon-14 come from?

Answer 23

Once living organisms

Question 24

True or False: the different minerals within the same rock can be formed at different times

Answer 24

True

Question 25

Events

Answer 25

A happening that occurs at a particular point in space at a definite time.

Question 26

Fission-track dating

Answer 26

A type of radioactive decay clock that uses the trails or tracks created by uranium fission decay to determine the age of geologic events.

Question 27

Period

Answer 27

A subdivision of geologic time. Smaller than an era, but still several tens of millions of years long.

Question 27

True or False: The ages obtained by these methods represent the ages of the elements that make up the rocks or minerals

Answer 27

FALSE

Question 27

Geologic column

Answer 27

A chart that shows the subdivisions of geologic time

Question 28

Era

Answer 28

The largest subdivision of geologic time

Question 29

How many eras are there?

Answer 29

4

Question 30

What are the four eras?

Answer 30

1. Cenozoic 2. Mesozoic 3. Paleozoic 4. Precambrian

Question 31

What does cenozoic mean?

Answer 31

Recent life

Question 32

What does mesozoic mean?

Answer 32

middle life

Question 33

What does paleozoic mean?

Answer 33

ancient life

Question 34

What was the era of dinosaurs?

Answer 34

Mesozoic

Question 35

What is magma?

Answer 35

Molten rock, under the crust

Question 36

Igneous

Answer 36

the type of rocks produced when melted material solidifies

Question 37

Sedimentary

Answer 37

The type of rocks created from sediments weathered from other pre-existing rocks.

Question 38

Metamorphic

Answer 38

The type of rocks produced when pre-existing rocks are altered without melting by pressure and heat.

Question 39

Protolith

Answer 39

A pre-existing rock from which other rocks are formed

Question 40

What does protolith mean?

Answer 40

Precursor rock

Question 41

Rock cycle

Answer 41

the transformation of igneous, sedimentary, and metamorphic rocks from one type to another.

Question 42

True or False: All three types of rocks can transform into the other two rock types OR into another version of itself.

Answer 42

True

Question 43

Minerals

Answer 43

the basic building blocks of rocks - elements joined together naturally

Question 44

True or False: All materials in a rock are classified as minerals

Answer 44

False

Question 45

Characteristics of a mineral:

Answer 45

1. naturally occurring 2. inorganic solid 3. has a fixed or narrowly limited chemical composition 4. has a definite internal crystal structure 5. exists within a defined range of pressure, temperature, and moisture 6. Has a unique set of physical properties

Question 46

True or False: Ice is a mineral

Answer 46

True

Question 47

True or False: glacial ice can be considered a rock

Answer 47

True

Question 48

What is the most abundant mineral group in the Earth's crust?

Answer 48

Silicates

Question 49

True or False: The mantle does not melt at one temperature and pressure, it melts over a RANGE of temperature and pressure combinations.

Answer 49

True

Question 50

Why does the mantle melt at a range of different temperatures and pressures?

Answer 50

Because it's made up of many different materials, each of which has a different melting temperature

Question 51

True or False: In addition to the decompression, a solid rock can melt into magma if the chemistry of the rocks change.

Answer 51

True

Question 52

How do you change a rock's chemistry?

Answer 52

Add water

Question 53

How is water added to the mantle?

Answer 53

Oceanic crust descending down into the mantle, bringing minerals that have water in their crystal lattices. When the minerals heat up, they break down and release the water.

Question 54

Plutonic

Answer 54

Pertaining to igneous rocks formed beneath Earth's surface

Question 55

Volcanic

Answer 55

Pertaining to igneous rocks formed ON earth's surface

Question 56

Physical weathering

Answer 56

Breaking down rocks through physical processes like freezing and thawing.

Question 57

Talus

Answer 57

A sloping mass of rocky fragments at the base of a cliff. Cone shaped

Question 58

How is physical weathering usually accomplished?

Answer 58

Through water and ice, freezing and expanding. But also wind, falling rocks, roots of trees and shrubs, etc.

Question 59

Chemical weathering

Answer 59

Breaking down rocks through chemical processes like acidic reactions.

Question 60

Metastable

Answer 60

A mineral that is unstable when subject to temperatures and pressures different from those of its formation but not liable to spontaneously change.

Question 61

Dissolution

Answer 61

To break apart or dissolve in solution.

Question 62

True or False: Water in soils or shallow rocks is often acidic because of water's reaction with carbon dioxide.

Answer 62

True

Question 63

Fun fact: CO2 is often 25 or more times higher in soils than in the air we breathe

Answer 63

woah

Question 64

Clasts

Answer 64

A grain of rock material weathered from a pre-existing rock

Question 65

Strata

Answer 65

A layer of material, often one of several layered upon one another.

Question 66

True or False: All clastic rocks require cement

Answer 66

True

Question 67

True or False: Clastic sedimentary rocks are classified according to the size of their grains.

Answer 67

True

Question 68

What size clasts are needed for a rock to be "conglomerate"?

Answer 68

>2 mm in diameter

Question 69

What size clasts are needed for a rock to be "sandstone"?

Answer 69

<2 but > 1/16 mm

Question 70

What are the smallest types of clastic sedimentary rocks?

Answer 70

Shale

Question 71

True or False: Virtually all fossil fuels are formed in and extracted from igneous rocks

Answer 71

FALSE

Question 72

What type rocks do we find fossils in?

Answer 72

Sedimentary

Question 73

Foliation

Answer 73

The structural or chemical arrangement into layers of materials in a rock. Like physically visible I think

Question 74

Do metamorphic rocks transform in a solid or liquid state?

Answer 74

Solid

Question 75

Where do metamorphic rocks come from in the crust?

Answer 75

Deep, where temps and pressure are highest.

Question 76

How do deeply buried metamorphic rocks get to the surface of earth?

Answer 76

Tectonic movements

Question 77

True or False: Examining the layers of foliation in metamorphic rocks can provide us with information about past tectonic events

Answer 77

True

Question 78

True or False: The rock cycle is responsible for the soil that provides roots for ALL LIFE

Answer 78

True

Question 79

Why are volcanoes formed at subduction points?

Answer 79

Because when the oceanic plate goes underneath another one, it creates pressure. Pressure supplies energy (electrical that leads to chemical reactions). Enough pressure leads to the water molecules being torn apart and interacting with other minerals in the area. This lowers the melting temperature. When temp is lowered, the rock melts and comes bubbling up to form volcanoes (like that video of Tonga volcano).

Question 80

What do all rocks within the type of rock (igneous, sedimentary, metamorphic) have in common?

Answer 80

Minerals

Question 81

Precipitate

Answer 81

A solid formed inside a liquid by a chemical reaction.

Question 82

Hydrothermal circulation

Answer 82

Movement or circulation of hot water.

Question 83

Hydrolysis

Answer 83

A type of chemical weathering in which water interacts with the minerals in the rock to form new minerals and leave ions in the water. Silicate-rich rocks and carbonate-rich rocks often experience this type of chemical weathering.

Question 84

Oxidation

Answer 84

A type of chemical weathering in which water interacts with the minerals in the rock to form new minerals and leave ions in the water. Metal-rich rocks often experience this type of chemical weathering.

Question 85

True or False: Many rocks don't form on the surface of the earth. They're formed within the crust or mantle and then pushed up to the surface to be eroded.

Answer 85

True

Question 86

Why do igneous rocks have large mineral deposits?

Answer 86

Because they form underground so the cooling time is longer.

Question 87

True or False: Igneous rocks can form above ground

Answer 87

True

Question 88

What happens to igneous rocks that cool above ground?

Answer 88

They cool and solidify very quickly, so there's no time for large minerals to form and they're often microscopic. Sometimes, like in the case of obsidian, there are no minerals at all.

Question 89

What is responsible for making most limestone?

Answer 89

Organisms making CaCO3

Question 90

Why does foliation occur?

Answer 90

Pressure is typically being applied in one direction, not uniformly in all directions (cuz gravity always pulls down)

Question 91

True or False: All metamorphic rocks are foliated

Answer 91

False

Question 92

True or False: Foliation always manifests PERPENDICULAR to the force.

Answer 92

True