Exam 1 Flashcards
The interior part of the Earth that is iron/magnesium rich, and has a plastic nature/rheology is the..
asthenosphere
How do we think we know where major physical boundaries are within the earth?
-deepwell drilling
-interpretation of seismic wave data
-calculations based on an ideal earth model
-measurement of the earth’s gravity field.
interpretation of seismic wave data
A large meteorite is proposed to have struck the earth ~65 million years ago, resulting in a mass extinction that killed off ~50% of all species, including the dinosaurs. Regarding this event, which of the following statements is false?
-One piece of evidence for the collision of a meteorite at 65 Ma is the presence of the element iridium in rocks at that time interval, at many locations throughout the world.
-The impact crater has been located off the coast of the Yucatan Peninsula
-Based on the size of the crater, the meteorite is interpreted to have been 10-50 km in diameter.
-It is hypothesized that a dust cloud was ejected into the atmosphere that was present for approximately a million years
-gravity studies of the rocks helped confirm the existence of the crater.
It is hypothesized that a dust cloud was ejected into the atmosphere that was present for approximately a million years.
In the earth’s crust, what is the average increase in temperature per 1 kilometer depth?
25 deg C
Place the following events in the proper order in which they occurred (according to conventional scientific interpretation of the fossil record), from oldest to youngest.
-dinosaurs
-fish
-insects
-bacteria
-mammals
- Bacteria Evolve
- Fish Evolve
- insects evolve
- dinosaurs evolve
- mammals evolve
Which of the following statements about the earth’s crust is false?
-continental crust is thicker than oceanic crust
-continental crust can be much, much older than oceanic crust
-continental crust is more dense than oceanic crust
-continental crust and oceanic crust have different average compositions.
Continental crust is more dense than oceanic crust.
Use the following diagram of the earth’s “Mechanical Layers” to answer the following questions.
E. (earth’s crust) - which layer is rigid and includes the crust and upper mantle
D. (2nd layer) - Which layer is the asthenosphere
C. (3rd layer) - Which layer is NOT the asthenosphere, but part of the mantle.
B. (4th layer) - Which layer is liquid
A. (Core layer) - No option
According to conventional scientific interpretation, the Earth is approximately 4.5 billion years old.
True
According to conventional scientific interpretation, approximately how long ago did the Big Bang occur?
13.7 Ga
What was the immediate significance of the evolution of photosynthesizing organisms?
It resulted in the release of Oxygen in the atmosphere.
What does the abbreviation Ma stand for?
Millions of years
Which of the following statements is false?
-The moon is thought to have been formed when a large meteorite impacted and blasted off a huge chunk of the earth
-The earth rotates around an axis that is tilted ~23.5 deg relative to the ecliptic plane.
-The oldest piece of Earth material that has been scientifically dated is a zircon crystal with an age of 4,404,000,000 yo
-It is thought that the oceans initially formed about 4 billion years ago.
-The first life is thought to have evolved ~600 million years ago.
The first life is though to have evolved ~600 million years ago.
Continental crust sticks up above the ocean’s surface and oceanic crust does not. The only reason for this is the thickness differences of the two different types of crust.
False
(Density differences also play a role. Because of oceanic crust’s greater density it “sinks” further into the mantle than does the more buoyant continental crust. This is the principle of Isostasy.
Match the following locations with their tectonic association.
(Convergent boundary, divergent boundary, or transform boundary)
San Adreas Fault
Himalaya
East Africa Rift
Mid Ocean Ridge
Japan
Blanco Fracture Zone
San Andreas Fault - Transform Boundary
Himalaya - Convergent Boundary
East Africa Rift - Divergent Boundary
Mid Ocean Ridge - Divergent Boundary
Japan - Convergent Boundary
Blanco Fracture Zone - Transform Boundary
Which of the following statements is false?
-Convergent plate boundaries are where two plates collide with each other
-divergent plate boundaries are where two plates move apart from one another
-Transform plate boundaries is where two plates move side by side.
-Hotspots do not occur at plate boundaries
-Hotspots do not occur at plate boundaries
What direction is the plate moving? (refer to map - Basho Island is an active volcano over a hotspot. The other islands, including Nesmith Island, are extinct volcanoes.)
Northeast
Very deep earthquake (>100km) occur where:
subduction zones
Why would oceanic volcanoes and seamounts within tectonic plates tend to form in a line?
The plate they are on is moving over a stationary hotspot.
Which of the following is NOT used as evidence for plate tectonics?
-magnetic reversals on the ocean floor
-Carbon dioxide levels in the atmosphere
-distribution of fossils
-earthquake and volcano distribution
-regional geologic patterns
Carbon dioxide levels in the atmosphere.
Which of the following statements is true?
-Earthquakes beneath subduction zones occur in random locations
-Volcanoes above subduction zones occur in disorganized clusters
-An ocean trench can form at a convergent plate boundary where a subduction plate physically drags down the surface of the earth.
-A subduction zone cannot occur where two oceanic plates converge.
-All of the above are true statements.
An ocean trench can form at a convergent plate boundary where a subduction plate physically drags down the surface of the earth.
Nesmith Island is an extinct volcano ~10 million years old. Appx how fast is the plate moving at this location?
Take distance (measure using scale) divided by time. In this question it was 100 km distance so the answer was 10km/m.y.
Which of the following locations is NOT associated with subduction zones:
The Cascade Mountains
The Andes Mountains
The Aleutian Islands
Hawaii
Philippines
Hawaii (hotspot)
Which of the following is not true:
-The average age of the continental crust is much older than that of the oceanic crust.
-The mantle is more dense than the oceanic crust
-oceanic crust is much thinner than continental crust.
-The oceanic crust is dominantly composed of granite.
The oceanic crust is dominantly composed of granite.
Which scientist was the first person to use geologic evidence to propose that the continents were drifting apart from a supercontinent he called Pangaea?
Alfred Wegener
Polymorphs are:
-minerals that can change color or shape under different pressures and temperatures.
-minerals that have the same chemical composition, but a different crystal lattice structure
-minerals that can have multiple cystal habits
-minerals that form in many different types of environments
-minerals that have several different chemical compositions
Minerals that have the same chemical composition, but a different crystal lattice structure.
A mineral that has well-formed crystal faces:
-grew in an environment where the cyrstal was not crowded during growth
-grew in an environment where the crystal was crowded during growth.
-must have precipitated in a high temperature environment such as magma
-must have precipitated in a cave.
grew in an environment where the crystal was not crowded during growth.
In the earth’s crust, what is the average increase in temperature with every 1 km depth increase?
25 deg C
What are the two most common elements in the earth’s crust?
Silicon and Oxygen
To be classified as a mineral, a substance must meet certain criteria. Which of the following is not one of these criteria?
-solid
-difinite chemical composition
-naturally occuring
-high melting temperature
-has crystalline structure
High melting temperature
The addition of a contaminant like H2O to a hot, pressurized rock:
Will lower the rock’s melting temperature
May lead to melting of the rock
occurs in subduction zones
ALL OF THE ABOVE (answer)
Minerals can form in several ways. Which of the following is NOT one of these?
-crystallized from a magma
-grown in a laboratory
-precipitated from groundwater
-precipitated from volvanic gas
grown in a laboratory setting
Which of the following is not true regarding minerals that exist in solid solutions?
-They can have variable composition from specimen to specimen.
-They exist as some intermediate composition between two end members
-They do not meet the criteria for being a mineral
-Olivine is an example of a solid solution mineral.
-All of the above are true.
They do not meet the criteria for being a mineral.
Look at the image below and indicate which rock melting mechanism the arrow is illustrating. (red arrow pointing up from curved line with pressure on y axis)
decrease in pressure
Look at the image provided…The Solidus (as shown) is the temperature at which a rock begins to melt, while the Liquidus is the temperature at which the rock is fulling melted. At temperatures between, the rock is partially molten. At the Lithosphere/Asthenosphere boundary (shown on the map), approximately what is the temperature at which the rock will begin to melt? (select the line between solid and zone of partial melting)
1,500 deg C in this example
Look at the image below and indicate which rock melting mechanism the arrow is illustrating. (red arrow pointing Right from curved line with temperature on x axis)
increase in temperature
The rock pictured below is most likely…….
the rock is varicolored, with pink, white, gray, and black minerals visible. These minerals are visible to the naked eye and interlock with one another.
intrusive
What type of tectonic setting would you expect to find Andesite volcanism?
Subduction Zone
Match the rock names with the compositional terms. (Felsic, Intermediate, Mafic)
Andesite
Basalt
Granite
Gabbro
Diorite
Rhyolite
Andesite - Intermediate
Basalt - Mafic
Granite - Felsic
Gabbro - Mafic
Diorite - Intermediate
Rhyolite-Felsic
Mauna Loa is a huge basaltic shield volcano that makes up some of the Big Island of Hawaii. Mt. Hood is a mostly andesite stratovolcano in the Cascades. What primarily governs the shape of these volcanoes?
Time passed since last eruption
Pyroclastic flow involve all of the following EXPECT:
ash
gas
rock fragments
lava
high velocity
lava
Cascade volcanism (such as Mt. Rainier and Mt. Hood) is associated with which type of plate tectonic boundary.
convergent
Which of the following would be a general example of an extrusive rock?
volcanic
plutonic
intrusive
phaneritic
NONE OF THE ABOVE
a volcanic rock
In 1985, the village of Armero, Columbia was the site of which volcanic disaster that caused 23,000 deaths.
lahar started by a small eruption melting the snowpack.
What type of tectonic setting would you expect to find basaltic volcanism?
-mid ocean ridge
-hotspots
-subduction zone
-continental rifting
-ALL OF THE ABOVE
All of the above
The rock pictured below is most likely….. The rock has visible rounded holes in it. The rock’s color is homogeneous gray, with less than 1% very small white crystals.
extrusive
Which of the following statements are not true?
-Felsic rocks have a higher SiO2 content than mafic rocks.
-Rhyolite magmas are typically hotter than Basaltic magmas
-H2O is a common gas dissolved in magma
-Felsic Magmas are more explosive than basalt magmas
-Mafic rocks are usually darker in color than felsic rocks.
Rhyolite magmas are typically hotter than basaltic magmas.
Which of the following does not belong
pillow lavas
oceanic crust
basalt
high silica content
effusive eruptions
high silica content
Match the compositional term with the correct SiO2 percentage
>70% SiO2 , <50% SiO2, 50-70% SiO2
Felsic, Intermediate, Mafic
Felsic - >70% SiO2
Mafic - <50% SiO2
Intermediate - 50-70% SiO2
