Plate tectonics and continental drift
**Which mechanism for continental motion did Wegener propose in his continental drift hypothesis? A The continents push through the rock of the ocean floor. B.The continents drift on tectonic plates that move due to mantle convection. C.The continents shift as a result of changes in Earth's magnetic field. D none of the above
A
Who proposed the continental drift theory?
Alfred Wegener
What evidence shows continental drift?
Appalachian mountains; same fossils across world, continents "fit" together, similar rock types, glacial evidence/climate
A geologist is studying a graben in the western United States. How did this feature form? A.strike-slip during convergence B.extension during divergence C.extension during convergence D.strike-slip during divergence
B
Geologists have learned of the existence of several supercontinents throughout Earth's history. Approximately when did the first of these supercontinents form? A.4.5 billion years ago B.3.1 billion years ago C.225 million years ago D.10,000 years ago
B
How does boiling water resemble a process that drives tectonic plate motion? A.The uneven distribution of thermal energy in the water causes denser molecules to sink and less dense molecules to rise. Similarly, the uneven distribution of thermal energy in Earth's interior causes denser rock to sink and less dense rock to rise. B.The uneven distribution of thermal energy in the water causes the water molecules to rise and sink in a continuous cycle. Similarly, the uneven distribution of thermal energy in Earth's interior causes soft rock in the mantle to rise and sink in a continuous cycle. C.The uneven distribution of thermal energy in the water stores energy that, when finally released, moves water molecules in random directions. Similarly, the uneven distribution of thermal energy in Earth's interior stores energy that, when finally released, moves soft rock in random directions. D.The uneven distribution of thermal energy in the water breaks the bonds of certain molecules, scattering atoms in random directions. Similarly, the uneven distribution of thermal energy in Earth's interior breaks apart certain rocks, scattering minerals in random directions.
B
Describe the Andes Mountains in relation to tectonic plates
It is a volcanic mountain range formed when the Nazca plate slid under the South American Plate
describe Hawaii in relation to the hot spot
Its a hot spot and is above a plate; the hot spot is moving from island to island; the biggest island is where the hot spot is currently, it is also the youngest island; the oldest island is the smallest and used to have the hot spot until it moved making more islands
What is a thrust fault?
Low angle reverse fault
What happens at a subduction zone?
More dense plate sinks below a less dense plate
What is ridge push?
The magma cools when it reaches the surface, solidifies, and is pushed aside as new magma pushes from below.
What is special about the APPALACHIAN mountains? how does it support continental drift?
The same mountains in North America are also found in Africa showing that Africa and North America were once together
is plate tectonics a theory or law? What is the relation with continental drift?
Theory; it explains how continental drift happens
What are fault-block mountains?
Type of mountains formed when crust was pushed up by tension
__________________ a piece of rock that gets "sliced" and put on land while some subducts
accretion
What drives plate tectonics?
convection currents
3 main things that drive plate tectonics
convection currents, ridge push, slab pull
*what happens when oceanic and oceanic collide?
denser one subducts; trenches; sometimes forms volcanoes
South America and Africa plate is what plate boundary
divergent
what plate boundary is the Mid-Atlantic ridge?
divergent
ridges are formed along...
divergent boundaries
*north America and the Eurasian plate is and forms what?
divergent; Mid-Atlantic ridge
what forces are associated with divergent and convergent
extensional; compressional
What is slab pull?
force that occurs in the mantle below subduction causing gravity to pull it down with it
what are the high points and low points in fault-block mountains
horst; graben
what is special about iceland?
its a divergent boundary above ground
what happens when continental and continental collide?Example?
little subduction but forms mountains; Himalayan mountains between India Plate and Eurasian plate
where is the oldest rock in an anticline found starting at the surface in the center?
middle=oldest; outside=youngest
where is the oldest rock in a syncline found starting at the surface in the center?
middle=youngest; outside=oldest
what are divergent, convergent, and transform boundaries
moving apart, moving towards each other, sliding past each other
what happens when oceanic and continental crust collide?
oceanic subducts; the friction of the subduction causing melting rock and volcanic mountain ranges, Example:South America + Nazca plate=Andes Mountains
during when are deep sea trenches formed
oceanic via oceanic;subduction
what is tension?
pulling force
___________________ _____________________ is when the atoms aline with the polarity causing alternating symmetrical bands
reversing polarity
what is the main evidence for continental drift?
seafloor spreading causing the continents to move (continents are connected to seafloor)
What is continental drift?
the idea that continents move around on Earth's surface
what is a monocline and how do you find the oldest rock from the surface?
there's one fold and you can't tell from surface
T or F, plates can change shape and size
true
DO NOT LOOK UNDERNEATH: FLIP THIS CARD OVER FIRST THEN FLIP BACK (normal and tension)
what fault is this and what stress is used
DO NOT LOOK UNDERNEATH: FLIP THIS CARD OVER FIRST THEN FLIP BACK reverse fault and compressional force
what fault is this and what stress is used
DO NOT LOOK UNDERNEATH: FLIP THIS CARD OVER FIRST THEN FLIP BACK strike slip and shear stress
what fault is this and what stress is used?
DO NOT LOOK UNDERNEATH: FLIP THIS CARD OVER FIRST THEN FLIP BACK (right to left) hanging wall, foot wall, foot wall, hanging wall
which is the hanging wall and foot wall
A geologist is comparing volcanism at two different locations. Location A is a volcanic arc system. Location B is a spreading center. Which conclusion is the geologist most justified in making? A.The volcanism is more explosive at location A than location B. B.The volcanism is more explosive at location B than location A. C.The volcanoes are active at location A and dormant at location B. D.The volcanoes are active at location B and dormant at location A.
A
How did scientists determine that the outer core is a liquid? A.Certain seismic waves that travel only through solids produce shadow zones in different parts of the globe. B.Scientists detected energy from certain seismic waves that travel only through liquids deep within Earth. C.Analysis of magma from deep within Earth's surface showed that it was chemically different from magma in Earth's mantle and crust. D.all of the above
A
How do the symmetrical magnetic reversal patterns of oceanic crust on either side of a mid-ocean ridge support the theory of plate tectonics? A.The patterns demonstrate that the oceanic crust is moving apart at a divergent plate boundary. B.The patterns demonstrate that the oceanic crust is coming together at a convergent plate boundary. C.The patterns demonstrate that sections of oceanic crust are sliding past each other at a transform plate boundary. D.The patterns do not support the theory of plate tectonics.
A
Pangaea became the continents we see today because of plate motion A.along divergent boundaries only B.only convergent boundaries only C.along both divergent and convergent boundaries D.none of the above
A
Why does the amount of oceanic crust in a tectonic plate change over time? A.Oceanic crust is continually recycled into the mantle and re-formed at mid-ocean ridges. B.The weight of the continents continually presses oceanic crust into the asthenosphere. C.Erosion from continental crust continually forms new oceanic crust. D.The amount of oceanic crust in a tectonic plate does not change over time.
A
What is anticline?
A fold in rock that bends upward into an arch
How does ridge push drive the motion of tectonic plates? A.Cooler, denser oceanic lithosphere sinks at subduction zones. B.Oceanic lithosphere slides downward and away from a mid-ocean ridge due to the higher elevation of the mid-ocean ridge relative to a subduction zone. C.The slow convection of mantle rock caused by the uneven distribution of thermal energy in Earth's interior moves tectonic plates above the mantle. D.none of the above
B
Which of the following topographical features drives tectonic plate motion through ridge push? A.the lower elevation of mid-ocean ridges relative to subduction zones B.the higher elevation of mid-ocean ridges relative to subduction zones C.the temperature difference between crust at a mid-ocean ridge and at a subduction zone D.the density difference between crust at a mid-ocean ridge and at a subduction zone
B
What is a byproduct of subduction? A.the creation of mid-ocean ridges B.the creation of fault-block mountains C.the recycling of oceanic crust D.the melting of continental crust
C
Which of the following statements is both true and supports the theory of plate tectonics? A.All of the crust on Earth is the same age as the planet: approximately 4.56 billion years old. B.All of the crust on Earth is the same age; it formed as molten material began to cool approximately 3.85 billion years ago. C.New crust is created at mid-ocean ridges, and old crust is destroyed at subduction zones; therefore, the oldest oceanic crust on Earth is only a few hundred million years old. D.Since Earth's crust first began to form, new oceanic crust has been continually forming; therefore, the oldest oceanic crust is approximately 3.85 billion years old, and the youngest oceanic crust is less than a day old.
D
Which statement does NOT summarize one of the lines of evidence used by Alfred Wegener to support his theory of continental drift? A.Glacial deposits indicate a different climatic condition. B.Similar fossils are found on widely separated continents. C.Similar geologic formations occur on both sides of the Atlantic Ocean. D.Bands of rock are older the farther their position from a mid-ocean ridge.
D
what is in the pacific and what is it?
Ring of fire which is a bunch of volcanoes at convergent plate boundaries
an example of a fault that causes many earthquakes
San Andreas in California
what is the difference between stress and strain?
Stress is the force on a material, strain is what happens to the material under a given stress. Example:tension--->normal fault
