MOD 2 QUESTIONS -GLY 108
docx
keyboard_arrow_up
School
Eastern Kentucky University *
*We aren’t endorsed by this school
Course
108
Subject
Geology
Date
Feb 20, 2024
Type
docx
Pages
2
Uploaded by MegaWhale2637
Alyssa Wright
GLY 108
Describe the differences between Earth’s crust, lithosphere, asthenosphere, and mantle. The mantle is characterized by peridotite, a rock made up of the mineral olivine and pyroxene. The asthenosphere is the denser yet weaker layer beneath the lithospheric mantle.The lithospheric crust is characterized by gneiss or continental crust and gabbro or oceanic crust.
What does the oceanic lithosphere consist of and how thick is it? Oceanic crust is found under the oceans and formed at spreading centers on oceanic ridges. The oceanic crust is about 4 miles thick. It is composed of several layers, not including the overlying sediment.
What are the main types of lithospheric plate boundaries described in terms of relative motions? Provide a real example of each. ★
Transform boundaries: where the crust is neither produced nor destroyed as the plates slide horizontally past each other. An example would be The San Andreas Fault.
★
Convergent boundaries: where the crust is destroyed as one plate dives under another. An example would be the Himalayan mountains.
★
Divergent boundaries: where new crust is generated as the plates pull away from each other. An example would be The Mid-Atlantic Ridge.
Why does the oceanic lithosphere almost always sink beneath continental lithosphere at convergent
zones? Young oceanic lithosphere is hot and buoyant with a low density when it forms but as it spreads away from the ridge and cools it becomes denser and it can sink into the hotter underlying mantle.
Along which type(s) of lithospheric plate boundary are large earthquakes common? Why? A divergent boundary. Earthquakes occur when the two tectonic plates move away from each other, magma then rises from the Earth's mantle to the surface, solidifying and creating a new oceanic crust.
Along which type(s) of lithospheric plate boundary are large volcanoes most common? Provide an example. Volcanoes are one feature that forms along convergent plate boundaries, this is where two tectonic plates collide, and one moves beneath the other. Deep ocean trenches and volcanoes are also examples of what can form along convergent boundaries.
Before people understood plate tectonics, what evidence led some scientists to believe in continental drift? Fossils, Ancient Rocks and different mountain ranges, would match up.
What evidence confirmed seafloor spreading? Scientists discovered that the magnetic poles of the Earth have reversed many times throughout its history. Magnetic reversals are also recorded in the rock making up the oceanic crust, and the pattern they
create is evidence of seafloor spreading.
Alyssa Wright
GLY 108
Explain how the modern theory of plate tectonics developed in the contest of the scientific method. Multiple scientific developments helped form plate-tectonics theory, these included the demonstration of the ruggedness and youth of the ocean floor; emergence of the seafloor-spreading hypothesis and associated recycling of oceanic crust; and confirmation of repeated reversals of the Earth magnetic field in the geologic past.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help