Plate Tectonics Test Prep
Describe the ocean-continental convergent boundary
(Subduction Zone) Large E.Q. & Explosive Volcanoes Cascade Mtns (OR, WA, CA) Andes Mtns (South America)
Describe the ocean-ocean convergent boundary
(Subduction Zone) Large E.Q. & Explosive Volcanoes Japan, Philippines, Aleutian Islands, Indonesia, West Indies, New Zealand
How much do tectonic plates move per year?
1-2 inches
How does the topography of the ocean floor support that tectonic plates have moved in the past?
Because oceanic crust cools as it ages, it eventually becomes denser than the underlying asthenosphere, and so it has a tendency to subduct, or dive under, adjacent continental plates or younger sections of oceanic crust.
How does the topography of the ocean suggest that tectonic plates have moved in the past?
Because relief matches dynamics of subducting ocean floor
How does GPS Data of moving tectonic plates suggest that tectonic plates have moved in the past?
By comparing the motion of several GPS stations in a region over time, scientists can detect motion of tectonic plates and infer deformation of the Earth's crust.
Why are average continental rocks are so much older than average oceanic rocks?
Continental crust is almost always much older than oceanic crust. Because continental crust is rarely destroyed and recycled in the process of subduction, some sections of continental crust are nearly as old as the Earth itself.
How does matter cycle by thermal convection and how does this relate to different types of plate boundaries?
Convection currents drive the movement of Earth's rigid tectonic plates in the planet's fluid molten mantle. In places where convection currents rise up towards the crust's surface, tectonic plates move away from each other in a process known as seafloor spreading
What are the three types of plate boundaries?
Convergent, divergent, transform
What natural phenomena's are related to divergent boundaries?
Earthquakes are common and magma (molten rock) rises from the Earth's mantle to the surface, solidifying to create new oceanic crust.
Describe the Continental crust of the lithosphere.
Felsic, Light Rocks, Granite, Less Dense, Thicker, Low Fe & Mg
How do earth quakes along trenches suggest that tectonic plates have moved in the past?
If two tectonic plates collide, they form a convergent plate boundary. Usually, one of the converging plates will move beneath the other, a process known as subduction. Deep trenches are features often formed where tectonic plates are being subducted and earthquakes are common at subduction zones as well.
What are the layers of the earth from core to outside?
Inner Core, Outer Core, Mesosphere, Asthenosphere, and Lithosphere.
How does the paleomagnetism of the ocean floor support the theory of plate tectonics?
It can be used to show that the oceanic crust has experienced seafloor spreading, where new crustal material pushes old crustal material away from the ridge.
How can the Seismic wave studies of lithosphere & asthenosphere suggest that tectonic plates have moved in the past?
It can image subducting ocean lithosphere
What are divergent boundaries? And what is the symbol for it?
It is when plates move away from each other, and it is two lines
What are transform boundaries? And what is the symbol for it?
It is when plates move sideways past each other, and it is one line
What are convergent boundaries? And what is the symbol for it?
It is when plates move towards each other, and it is a triangular patterned line
Describe the continental-continental boundary
Large Earthquakes Only Himalaya, Alps, Zagros Appalachian (ancient)
What is the outer core made of?
Liquid Fe and Ni
Describe the ocean crust of the lithosphere.
Mafic, Dark Rocks, Basalt, More Dense, Thinner, High Fe & Mg
How do metamorphic rocks relate to plate tectonics?
Metamorphic rocks formed at areas of compression are formed at convergent plate boundaries. If one could increase the rate of plate tectonic movements, one would also increase the rate by which metamorphic rocks form.
What are some divergent boundary examples?
Mid-ocean ridges where Sea-floor Spreading occurs and Magma rises up under ridge. Pushes ocean floor apart3. Magma cools, crystallizes forming new ocean floor1. Ocean floor pulled apart Magma rises up under ridge Mid-ocean ridges where Sea-floor Spreading occursMagma4. America & Europe/Africa get further apart and ocean gets wider
What are the three types of convergent boundaries?
Ocean-ocean, ocean-continental, continental-continental
How do you calculate the rate of plate motion when given ages of ocean floor or hot spot volcanoes and distances between them?
Recall that a rate of motion, commonly called "speed," is a distance divided by the amount of time it took to cover that distance. Divide the distance from peak 4 (measured in km) by the age (in Ma) to get the average rate of plate motion away from the ridge.
What is the inner core made of?
Solid Fe and Ni
How would you describe the Asthenosphere, hard, or solid but weak?
Solid but soft/weak
How would you describe the lithosphere?
Solid, rigid plates of Plate Tectonics
How do the locations of earthquakes and volcanoes suggest that tectonic plates have moved in the past?
Tectonic activity such as earthquakes, volcanic eruptions and the formation of mountain ranges commonly occurs along the boundaries of the moving plates.
What are some transform boundary examples?
The San Andreas Fault and Queen Charlotte Fault are transform plate boundaries developing where the Pacific Plate moves northward past the North American Plate.
What are some convergent boundary examples?
The collision between the Eurasian Plate and the Indian Plate that is forming the Himalayas. Subduction of the northern part of the Pacific Plate and the NW North American Plate that is forming the Aleutian Islands. Subduction of the Nazca Plate beneath the South American Plate to form the Andes.
What are some examples of passive continental margins?
The collision between the Eurasian Plate and the Indian Plate that is forming the Himalayas. Subduction of the northern part of the Pacific Plate and the NW North American Plate that is forming the Aleutian Islands. Subduction of the Nazca Plate beneath the South American Plate to form the Andes.
What features are caused by divergent plate boundaries?
The features most commonly associated with divergent boundaries between tectonic plates are rift valleys, ocean ridges, fissure volcanoes, and underwater mountain chains.
What is another name for the Mesosphere?
The mantle
What is the theory of plate tectonics?
The theory of plate tectonics explains the formation, movement, and subduction of Earth's plates. AKA The system of ideas behind plate tectonics theory suggests that Earth's outer shell (lithosphere) is divided into several plates that glide over the Earth's rocky inner layer above the soft core (mantle).
How do igneous rocks relate to plate tectonics?
They float on top of the hot, deep layers of the earth where magma is found. The plates can either get closer together or drift apart, and this tectonic plate movement gives us the right conditions for the formation of igneous rocks, which are rocks that form from the cooling and solidifying of magma.
What are some examples of active continental margins?
Trench (up to 11,000m deep) parallel to a continental volcanic arc Convergent Plate Boundary Marks where ocean crust is subducting under edge of continent Regular large E.Q., tsunamis and volcanic eruptions Narrower continental shelf than many passive margins Andes & Cascade Mtns, South & Southwest Alaska
What features are caused by convergent plat boundaries?
Volcanoes, volcanic arcs, mountains (especially in arcs), oceanic trenches, and island arcs.
What natural phenomena's are related to convergent boundaries?
Where they collide and one plate is thrust beneath another (a subduction zone), the most powerful earthquakes, tsunamis, volcanic eruptions, and landslides occur.
How does the age of the ocean floor suggest that tectonic plates have moved in the past?
Because it gets older moving away from ridge on both sides (Isochrons mirror on both sides)
How can Movement of lithosphere over fixed hot spots suggest that tectonic plates have moved in the past?
Because it produces straight chain of extinct volcanoes w/ active one at end over the hot spot
What is a passive continental margin?
A passive continental margin occurs where the transition from land to sea is not associated with a plate boundary. The east coast of the United States is a good example; the plate boundary is located along the mid Atlantic ridge, far from the coast.
What natural phenomena's are related to transform boundaries?
A transform boundary causes a fault between two plates of the lithosphere, which will slide past one another. This motion does not create or destroy crust and will cause earthquakes, but no volcanoes.
How do Sedimentary rocks relate to Plate Tectonics?
All the igneous rocks which are the basis of the rock cycle are formed by plate tectonics. When the igneous rocks get eroded, they turn into sedimentary rocks. The layers of the sedimentary rocks are generally recycled by plate tectonics
What is an active continental Margin?
An active continental margin is a coastal region that is characterized by mountain-building activity including earthquakes, volcanic activity, and tectonic motion resulting from movement of tectonic plates.
