Geology HW 05

24 July 2022
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question
Which of the following lithospheric plates is not included among the seven largest?
answer
the Philippine plate
question
Earth's lithospheric plates are composed of crust and which of the following layers?
answer
the outermost portion of the mantle
question
Which of the following processes can be observed at the margins of lithospheric plates?
answer
faulting earthquakes volcanoes mountain building
question
In studies of rock obtained from ocean basins all over Earth, the oldest ages obtained are approximately 200 million years before the present. Why have no older oceanic rocks been discovered?
answer
Due to tectonic activity, rocks on the ocean floor are continually recycled.
question
Currently the Juan de Fuca plate is interacting with the North American plate where inland volcanoes and deep focus earthquakes are occurring. What type of plate boundary is this
answer
a convergent plate boundary
question
Which type of tectonic boundary is the result of two tectonic plates colliding with each other?
answer
Convergent boundary
question
At a subduction zone where oceanic lithosphere meets continental lithosphere, which would subduct and why?
answer
The oceanic lithosphere would subduct because it has a higher density at 3.0 grams per cubic centimeter.
question
Why are volcanic chains associated with convergent boundaries?
answer
Partial melting occurs due to subduction.
question
Plate A has oceanic lithosphere on its leading edge that is 10 million years old. Plate B has oceanic lithosphere on its leading edge that is 200 million years old. Which plate will be subducted if they collide with each other, and why?
answer
Plate B will subduct because it is olderโ€”and therefore colderโ€”and more dense.
question
In a collision between two continental plates, can a continental plate subduct? Why or why not?
answer
Continental plates are too buoyant to subduct.
question
Which properties of a lava lamp are important to remember when modeling convection?
answer
The lava lamp contains two liquids with different densities that do not mix and that expand at different rates when heated.
question
Why does the orange liquid rise when the lava lamp animation is plugged in?
answer
Although both liquids expand when heated, the orange liquid expands more.
question
What is the appropriate term for the movement of the orange liquid in the lava lamp animation?
answer
convection
question
Where in a lava lamp would the density of both materials be equal?
answer
near the middle of the lamp
question
What would happen to the orange liquid in the lava lamp if heat did NOT conduct out of the top of the lava lamp?
answer
The orange liquid would stay near the top of the lava lamp.
question
What would happen in the lava lamp if the orange liquid were denser at warmer temperatures than the blue/clear liquid shown in the animation?
answer
The blue/clear liquid would rise toward the top when the lamp was turned on, whereas the orange liquid would sink.
question
Which of the following happened first?
answer
The North Atlantic Ocean begins to form. The mountains of Southern Asia and Europe begin to form. *The Appalachian Mountains begin to form.* The formation of Pangaea
question
Continental rifting formed what?
answer
North Atlantic Ocean
question
what occurred about 21,000 years ago?
answer
The formation of the ice age glaciers.
question
Which of the following statements best describes Wegener's idea of continental drift?
answer
Continents were formerly in different positions on the Earth and have shifted to their present locations over time.
question
How was the fossil record of ancient life used to support Wegener's hypothesis about Pangaea?
answer
Fossils of identical organisms were found on several continents, indicating the continents were once joined.
question
Late Paleozoic sedimentary rocks often contain extensive coal seams that were used to support the existence of Pangaea. What would the climate have been at that time and at the location where the coal deposits were formed, and what would it indicate about the continent's past latitude?
answer
Warm, humid climate near the Equator
question
When matching up once-joined continents such as South America and Africa, the coastlines do not fit together as nicely as the continental shelves. Why might this be the case?
answer
The continental shelves are the edges of the continent. The shoreline simply shows where the sea level is in relation to topography.
question
What evidence supports that the glaciers on the southern continents were once part of a single, massive ice sheet?
answer
Striations
question
Which of the following is a layer of the Earth that is classified NOT by composition, but by physical properties?
answer
Asthenosphere
question
Oceanic lithosphere contains oceanic crust and the __________.
answer
outermost part of mantle beneath the oceanic crust
question
How is the thickness of the lithosphere going to change as it moves away from a divergent plate boundary?
answer
Lithosphere will thicken as more mantle is added.
question
What is the main material being subducted at an ocean-continent convergent boundary?
answer
Oceanic lithosphere
question
What are two differences between oceanic crust and continental crust?
answer
The continental crust is thicker and less dense than oceanic crust.
question
How do plates move at divergent plate boundaries?
answer
Plates move apart.
question
How do plates move at convergent plate boundaries?
answer
Plates move toward one another.
question
How do plates move at transform plate boundaries?
answer
Plates slide past one another.
question
In general, where do earthquakes AND volcanic eruptions occur?
answer
divergent plate boundaries convergent plate boundaries
question
What forms at divergent plate boundaries?
answer
new oceanic lithosphere
question
In general, where do volcanoes form in subduction zones?
answer
on the overriding plate, away form the convergent boundary
question
Why are volcanoes NOT found at transform boundaries?
answer
Transform boundaries do not cause changes to the pressure, temperature, or composition of the mantle.
question
The East African rift is a divergent plate boundary that is splitting the continent of Africa into two pieces. What will eventually form around this divergent boundary?
answer
an ocean
question
Where are tectonic plates located?
answer
at Earth's surface
question
What are the three types of plate boundaries?
answer
divergent, convergent, and transform
question
Which of the following statements about earthquakes with magnitude greater than 4.0 is most accurate?
answer
Earthquakes with magnitude greater than 4.0 occur in a pattern than correlates closely with plate boundaries.
question
Which plate boundary is NOT associated with volcanic eruptions?
answer
transform
question
Which phenomenon can explain the presence of volcanoes in the middle of the Pacific Ocean?
answer
hot spots
question
Which type of plate boundary is most closely associated with uplifting continental regions and mountain building?
answer
convergent boundaries