The velocity of compressional waves in the lower part of the oceanic crust averages about 7 km/s. What rock type is most consistent with this observation as well as with your other knowledge of the oceanic crust?
What evidence suggests that the asthenosphere is partially molten?
What evidence indicates that Earth’s outer core is molten and composed mostly of iron and nickel?
What is the depth to the core, and how do we know it?
What is the difference between conduction and convection? Which process is more efficient in transporting heat through the mantle?
Would the temperature at the Moho beneath a continental craton be hotter or cooler than the temperature at the Moho beneath an ocean basin?
How can features of mantle convection, such as rising and descending convection currents, be seen by seismic tomography?
How can a mountain float on the mantle when both are composed of rock?
How do igneous rocks become magnetized when they form? How does the magnetization of sedimentary rocks differ from this process?
What evidence supports the hypothesis that Earth’s magnetic field is generated by a geodynamo in its outer core?
Does the magnetic field change by an observable amount over the span of a human lifetime? What does the answer suggest about convective movements in the outer core?