Exam 1

Question 1

What is geology? Not just the study of rocks!

Answer 1

Geology is the study of earth’s composition, behavior, history, and environment. It relies heavily on Biology, Chemistry, Physics, and Math. Often is called Geoscience/Earth Science

Question 2

How old is the earth?

Answer 2

4.6 billion years

Question 3

Hadean

Answer 3

“Beneath the Earth”; All rocks still molten (think as hot as hades)

Question 4

Archean

Answer 4

“Ancient”; Oldest rocks

Question 5

Proterozoic

Answer 5

“Former Life” ; Simple organisms

Question 6

Phanerozoic

Answer 6

“Visible Life”; Phanero means visible

Question 7

Precambrian

Answer 7

This sums up everything before/except the Phanerozoic Eon

Question 8

Plate tectonics

Answer 8

The unifying theory of understanding the Earth Essential theory to explain Earth processes, Plates move very slow…. <10 cm/yr!

Question 9

How does science work? Does science “prove” things? What is required for something to be considered science?

Answer 9

Science is NOT about proving things, It’s all about gathering data and testing Ideas. DATA is required for something to be considered Science

Question 10

Scientific Method

Answer 10

Find out what the problem is
Collect Data
Analyze data’
Then form a hypothesis (which is your explanation of the data you gathered and why it looks the way it looks)
Test Hypothesis (you or others can do this step), which can take a long long time until enough people ask: Does the hypothesis agree with other data? Does the Hypothesis predict behavior? If Yes: Hypothesis becomes a theory. If No: Hypothesis must be modified or rejected.

Question 11

Know Foucault’s experiment & Eratosthenes experiment. What did each demonstrate?

Answer 11

Foucault’s: Experiment Tells us earth rotates around the poles (pendulum that swung and slowly changed direction anywhere except the poles)

Eratosthenes: Experiment found the circumference of the Earth (had assistant walk hella far and measured the distance, then took data from degree of shadow at noon because sun was directly above him.

Question 12

What does a light year measure?

Answer 12

The distance that light travels in a year.

Question 13

Wavelength

Answer 13

Length from Crest to crest on a wavelength graph

Question 14

Period

Answer 14

Time for one wavelength

Question 15

Frequency

Answer 15

Wavelengths per second

Question 16

Amplitude

Answer 16

Distance between the peak and equilibrium of a wave

Question 17

Which is higher in frequency? blue light or red light?

Answer 17

Blue light is on the higher frequency end of the spectrum. Red on the lower frequency.

Question 18

Know the Doppler Effect and how it relates to the universe, red and blue shift.

Answer 18

The Doppler Effect describes how sound waves from a moving sound source change frequency based on whether they are moving toward or away from a stationary listener (and how fast it is going.) Doppler Effect helps us determine that the universe is expanding because distant galaxies are red shifted meaning they are moving away from us.

Question 19

The Big Bang theory. Know its basic description and what the simple evidence that supports it.

Answer 19

The Big Bang Theory is where all the mass and energy of the universe was packed into a small single point. It then exploded and has been expanding ever since.

Question 20

Know the eight planets. Also, know why Pluto is not considered a planet.

Answer 20

Mercury, Venus, Earth, Mars, Saturn, Jupiter, Uranus, Neptune.
Pluto doesn’t fit the definition of a planet which is a large solid body orbiting a star, has nearly spherical shape, and cleared its neighborhood. (also apart of Kuiper Belt)

Question 21

What are ‘Terrestrial’ and ‘Jovian’ planets? Why are the different?

Answer 21

Terrestrial planets are Mercury, Earth, Venus, and Mars. They have a crustal surface.
Jovian planets are Saturn, Jupiter, Uranus, and Neptune. They are made of gas.

Question 22

What else is in the solar system other than planets?

Answer 22

Moons, The Sun, asteroids, comets, meteorites, satellites, aliens 0_0

Question 23

Know the Nebular theory and how it explains the formation of the solar system.

Answer 23

The Nebular theory is where H and He left over from the big bang condenses, and clumps together, with heavier elements forming from fusion and supernovae. Eventually all of this matter starts spinning and flattens into a disk due to gravity. Towards the center, it is hotter and denser than the outside. Nuclear fusion occurs towards this hot and dense center area, then the sun is born. More dust in the inner portion of the nebula forms the terrestrial planets and more ice/gas on the outside of the nebula forms the jovian planets.

Question 24

Why are the planets all in the same plane (except Pluto)? Why are the terrestrial and jovian planets where they are relative to the sun?

Answer 24

During our solar system’s formation, every planet formed from a disk of dust which surrounded the sun. This disk was all in a plane as it rotated around the sun, and formed the current day planets.
Pluto is not on this plane because it is a captured object in the nebular theory rather than a formation from the nebular theory.
Terrestrial planets were created because through the nebular theory, the denser heavier matter rotated closer to the sun, while lighter less dense objects rotated further away from the sun.

Question 25

How did the moon form and what is our evidence for this?

Answer 25

The moon formed when a large impact hit the Earth as it was forming, and a chunk of the Earth flew off. This chunk got trapped in Earth’s gravitational pull, so it began to orbit the Earth.

Question 26

What is differentiation and how does it impact the density structure of a planet?

Answer 26

Differentiation is defined as a process where the interior of earth differentiates into a nickel-iron core and a rocky (silicate) mantle.

Question 27

Solar wind, what is it, and what protects us from it?

Answer 27

“All this stuff that the sun is somewhat sneezing at us all the time. Basically charged particles that react to magnetic fields, which are made up of protons and electrons.” -Earth’s Magnetic fields force dangerous particles around the earth and don’t let them come to the earth’s surface. Particles do get caught in the poles.

Question 28

Earth has a dipole magnetic field. Know its features and what it protects us from.

Answer 28

Dipole (two poles) magnetic field reflects solar winds and protects us from solar radiation

Question 29

What generates the magnetic field on Earth?

Answer 29

Geodynamo (Flow in the liquid iron outer core) generates Earth’s magnetic field

Question 30

What causes the Aurorae?

Answer 30

Charged Particles that get caught in earth’s poles forms the Aurorae

Question 31

What causes air pressure? Where is it highest? Lowest?

Answer 31

Caused by the weight of overlying material (upper atmosphere has less material above it, which means the pressure is lower up there, while the atmosphere we live in has more material, which means the pressure is higher here). Highest point of pressure would the the core of the earth, the highest atmospheric point of pressure would be the troposphere. The Lowest point of atmospheric pressure would be the Exosphere

Question 32

Earth has a stratified atmosphere. What does that mean? What are the two dominant

Answer 32

Means that the earth is divided into layers, and the two dominant elements are N2 and O2, but N2 is more

Question 33

What is convection and where does this happen on Earth?

Answer 33

- Convection is the method of heat transfer used in fluids. (think of a lava lamp) - The interior of earth is where convection happens.

Question 34

Is Earth’s composition uniform? What is the dominant element that comprises the bulk Earth? What are the two dominant elements in the crust?

Answer 34

- No - Iron - Oxygen and Silicon

Question 35

Know the layers of Earth: crust-mantle-core, lithosphere-asthenosphere. Which are solid? Which are liquid? What layers are based on composition? What layers are based on how they react to stress (how they deform)?

Answer 35

Solid: Crust, Mantle, Inner Core Liquid: Outer Core Based on Composition: Crust, Mantle Based on reaction to stress: Lithosphere and Asthenosphere

Question 36

What is the Moho? What is the Brittle-Ductile transition?

Answer 36

- Moho is the lower boundary of the crust that separates the crust from the upper mantle. - Brittle-Ductile transition is defined as 2 things. The first is a significant change in rock physical properties. The second is the depth at which earthquakes do not occur.

Question 37

Earth’s dimensions: No need to memorize the numbers, but you should know which layers are big (volume-wise) and which are small.

Answer 37

Crust - not too big Mantle - pretty big Core - Outer Small Core - (inner) smallest

Question 38

Does lithosphere = crust? Does asthenosphere = mantle?

Answer 38

Lithosphere is NOT the crust, but it includes the crust and upper mantle. Asthenosphere is the same, but includes everything in the upper mantle and below

Question 39

The Crust: How many basic types? What are the compositions? What are the general rock types for each? Which is more/less dense? Which is thicker/thinner?

Answer 39

Crust is made of: Upper (Felsic; less dense, thicker, Floats higher) Lower (Mafic; more dense, thinner, Floats lower)

Question 40

The Mantle: What is the composition? What is the general rock type? What is the density relative to the crust?

Answer 40

- Ultramafic rock called peridotite - Ultramafic - Really dense, low silicon and oxygen compared to the crust

Question 41

Density of earth…what does density tell us about rocks on the surface? Near the core? Is density uniform?

Answer 41

Density tells us clues about the internal structure of the Earth, and how it’s inner layers are denser than its outer layers Density is not uniform

Question 42

Are there dominant elevations on Earth? Why?

Answer 42

Yes, ignoring oceans Earth’s surface is dominated by two elevations: - Land is between 0-2kn - Most of the Sea Floor is 3-5km below sea level

Question 43

What does felsic, mafic, and ultramafic mean? Know at least one rock name for each of these.

Answer 43

Felsic- More silica and less dense. (Granite) Mafic- Less silica and more dense. (Basalt) Ultramafic- Little silica and very dense. (peridotite)

Question 44

What element is the core dominantly made of? Is the core solid or liquid or both?

Answer 44

Core is mostly made of Iron, and is liquid in the outer and Solid in the inner

Question 45

Who was Alfred Wegener? What contribution did he make to geology?

Answer 45

Wegner was a meteorologist who first hypothesized Continental Drift.

Question 46

What was Pangaea? When was it together? What were the five lines of evidence for continental drift?

Answer 46

Pangea was the term used for the “SuperContinent” formed when you connect all the continents together. It is greek for “All Land”. Five lines of Evidence: Continents fit together Locations of Past glaciations Distribution of Tropical Climates Distribution of fossils Matching of rock units across ocean basins

Question 47

What was the fatal flaw in Wegener’s hypothesis?

Answer 47

Wegner believed that the continents moved at around 30m/yr, which was about 1000x too fast, and he did not have a driving mechanism for how they exactly moved.

Question 48

What are apparent polar wander paths and what did they help scientists realize? Do the magnetic poles actually wander all over the globe or do the mainly stay near the north and south geographic poles?

Answer 48

The wandering poles show that the continents were have been together and followed a similar path in relation to the magnetic field. The poles typically stay in the general area of the north and south magnetic poles, though they do “wander” around those areas.

Question 49

Magnetic inclination & declination: What do these terms refer to and how do they differ? What can geologists determine from inclination and declination?

Answer 49

Inclination in ancient rocks tells us the apparent distance (in latitude) between the site where the rock was formed and the magnetic north pole. Declination in ancient rocks tells us which direction pointed to the north magnetic pole when the rock was formed (and thus give E-W distance, or longitude)

Question 50

How is magnetism recorded in rocks? How is magnetism locked into igneous rocks? What about magnetism in sedimentary rocks?

Answer 50

By looking at inclination and declination in ancient rocks, we can measure their magnetism to see how the earth’s magnetic poles have moved over time. Magnetism in rocks is recorded with inclination (latitude) and declination (longitude) which indicate the distance between the rock and the Earth’s magnetic field. Magnetic minerals in sedimentary rocks align with magnetic poles and With igneous rocks, minerals in cooling lava align with Earth’s magnetic field. Because of this Earth’s igneous rocks inherit the Earth’s magnetic field at the time of their formation. We can detect weak magnetic fields in igneous rocks

Question 51

How can scientists use paleomagnetic data to reconstruct latitude and longitude in the deep geologic past?

Answer 51

Inclination tells us the apparent distance (latitude) between the site where the rock was formed and the magnetic north pole. Declination tells us which direction pointed to the north magnetic pole when the rock was formed (and thus give E-W distance or longitude)

Question 52

What is bathymetry? What does morphology mean?

Answer 52

Bathymetry is Oceanic topography describing the sea floor Morphology is the branch of biology that deals with the form of living organisms, and with relationships between their structures. Or the external structure of rocks in relation to the development of erosional forms or topographic features. May be maybe not.

Question 53

Be able to describe the following bathymetric features: Mid ocean ridge, fracture zone, abyssal plain, trench, guyot, seamount. Where are these features found on the seafloor?

Answer 53

Mid-Ocean Ridge: area where seafloor spreading occurs; Located in the center or so of the atlantic ocean between the Americas and Europe Fracture zone: Offset areas on the mid ocean ridge that transform Abyssal Plain: Flat area before the slope Trench: Sudden dip down to deep part of the ocean Guyot: A seamount with a flat/eroded top Seamount: A submarine mountain

Question 54

On the ocean floor, where is heat flow highest? Ridges? Trenches? Abyssal plains? Why is the heat flow high?

Answer 54

Heat flow is highest at the Ridges because the crust at the ridges is less dense than surrounding crust

Question 55

How does sediment cover thickness change away from ocean ridges? Why?

Answer 55

Sediment cover thickens as it moves away from ridges because they are the older parts of the crust

Question 56

Why do most submarine earthquakes occur at ridges and trenches?

Answer 56

More heat flow mixed with thinner crust in these areas makes strike-slip faults occur easier (those faults cause earthquakes)

Question 57

Seafloor Spreading: Know the details. Whose idea was this?

Answer 57

Henry Hess came up with dis | Crust made at ridges and consumed at trenches

Question 58

Subduction: Know the details. What kind of crust can’t subduct? Why? What if both plates are oceanic…which subducts?

Answer 58

Continental crust cannot subduct under oceanic crust Because continental crust is less dense than oceanic crust, so it rises higher than Oceanic crust. The less dense crust will not subduct

Question 59

Know the evidence for seafloor spreading and subduction.

Answer 59

Evidence for Seafloor spreading: Older crust is further from ridges than younger crust Eruptions of material

Question 60

Mid ocean chrons are symmetrical…why?

Answer 60

These rocks record reversals in the strength and direction Earth’s magnetic.

Question 61

Magnetic reversals: Are magnetic shifts regular? Is this process fast or slow? How do we know this?

Answer 61

Long process. Very slow. A few million years for a slight shift.

Question 62

What are tectonic plates? Does a Plate = A Continent? Does a plate have approximately uniform composition?

Answer 62

Tectonic plates are Earth’s lithosphere divided into a number of pieces. Most plates are made up of continental and oceanic crust, so no, a plate does NOT equal a continent. Yes, plates are made from basaltic rocks (oceanic crust) and granite rock ( continental crust)

Question 63

What is meant by active margin? Passive margin? How do they differ? What are the features of both?

Answer 63

* Active Margin: A continental shoreline that IS a plate boundary * Passive Margin: A continental shoreline that IS NOT a plate boundary

Question 64

Know the three types of plate boundaries and know the details and motions of each type.

Answer 64

1- Divergent- Moves apart, Produce new crust, Exs Mid atlantic Ridge/ East Pacific Rise. Causes sea floor spreading 2- Convergent- Moves together- Consume old crust- India into asia, NW coast of U.S . SW coast of South America. Effects of movement Subduction or collision 3- Transform- Moves past each other- doesn’t consume or create crust. Ex- North Anatolian Fault (Turkey), Dead Sea Fault (Israel, Jordan), San Andreas Fault. Effects of movement- Transform Faulting

Question 65

Why are mid ocean ridges elevated? Why does continental crust contain the oldest rocks on Earth...why not oceanic?

Answer 65

They are elevated because new oceanic crust is warmer and less dense, and very little lithosphere has been added close to the ridges. Further from the ridges, the cool crust is more dense, and the thicker lithosphere adds even more weight, pulling the whole lithosphere down into the asthenosphere

Question 66

Pillow basalts, Black smokers, what are they and where do they form?

Answer 66

Black smokers :Magma heats water and it jets out of these chimney-like vents. The water is black because of dark colored minerals. Strange critters live here! Pillow basalts Pillow Basalts: When lava erupts underwater, instead of making coherent flows, it forms rounded blob-like pillows. Commonly called pillow basalts

Question 67

What drives plate tectonics? Know the details. What drives ridge push? What drives slab pull? Know how each works.

Answer 67

Tectonics is driven by ridge-push and slab-pull, both driven by gravity Divergent boundaries are driven by ridge-push, which is driven by gravity Slab-Pull force drives subduction from gravity Dense lithosphere sinks and once it starts to sink the density difference pulls the rest of the plate with the sinking slab

Question 68

Accretionary wedge/prism, volcanic arc, slab, Wadati-Benioff zone, megathrust earthquakes, island arc. Know these terms in detail.

Answer 68

Accretionary prisms-sediments scraped off subducting plates are smeared and welded onto the overriding plates Volcanic arc- Volcanic belt on an overriding plate. Descending plate contains fluids, squeezed out at about 150 km depth. Causes the overlying plate to partially melt. Magma burns upward, fueling volcanic belts are curved. Wadati-Benioff zone- These earthquakes can be produced by slip along the subduction thrust fault or by slip on faults within the downgoing plate as a result of bending and extension as the plate is pulled into the mantle. Megathrust earthquakes-occurs along the interface between the upper and lower plate, pattern of the earthquakes outlines the location and shape of the lower plate Island arc-chain of volcanic islands that form behind a subduction zone

Question 69

Why are volcanoes associated with subduction zones?

Answer 69

A subducting plate pushes partially melted magma from the asthenosphere through the lithosphere into a magma chamber, forming a volcano

Question 70

Transform boundaries: how do their motions work with spreading centers (divergent boundaries)?

Answer 70

Transform boundaries offset divergent boundaries and mid-ocean ridges

Question 71

Mid ocean ridges are commonly associated (are connected to) with what other type of plate boundary?

Answer 71

Divergent plate boundaries

Question 72

What is a triple junction?

Answer 72

This is a boundary where three tectonic plates meet.

Question 73

Hot Spots: know at least 1 example. Are hot spots rare?

Answer 73

They are rare in comparison to volcanoes formed along plate boundaries. One example would be the Islands of Hawaii

Question 74

What is a rift? Where is one today? What will a rift evolve into? Does the crust get thinner or thicker during rifting?

Answer 74

A rift is a stretching of continental material which causes the crust to thin. A rift that exists today is the East African Rift. A rift will eventually evolve into a mid-ocean ridge. The crust gets thinner during rifting.

Question 75

How do subduction zones die? Why? Where is a current-day subduction zone? Where is a current-day collision? Does the crust get thinner or thicker in a collision zone?

Answer 75

The subduction zone eventually swallows the dense oceanic crust, and the remaining crust isn’t dense enough to subduct, so the subduction zone is sealed. The crust gets thicker in a collision zone. A modern day subduction zone is the Oregon profile.

Question 76

Be able to give a current-day location of each type of plate boundary (be specific!).

Answer 76

Transform: San Andreas fault Convergent: Cascade mountain range Divergent: Mid Atlantic Ridge