Week 2-3 quiz - Continental drift, exploration of the oceans and seafloor spreading Flashcards
Which of these properly illustrates the principle of isostasy?
Mountains stand high because they are gravitationally balanced by their deep crustal roots.
Igneous rocks ________.
are formed through the freezing or crystallization of a melt
Deep-oceanic trenches are features of ________ plate boundaries.
Convergent
The oldest basalts on the ocean floor are about ________ years old.
200 million
The geotherm is the rate of change of:
Temperature with depth in Earth’s interior
The thickness of clay and planktonic microskeletons is greatest ________.
At the edges of ocean basins
Tectonic plates move at rates that are approximately ________.
1 to 15 cm/year
If a geologist discovered coal in a modern-day cold, snowy location, he or she could conclude that _______.
the area was once covered with swamps and/or jungles
Beneath a blanket of sediments, oceanic crust is primarily composed of ________.
basalt
The mid-ocean ridges are elevated above the surrounding sea floor because ________.
ridge rocks are hot and therefore have relatively low density
Under the theory of plate tectonics, the plates themselves are ________.
discrete pieces of lithosphere at the surface of the solid Earth that move with respect to one another
On either side of a mid-ocean ridge, the lithosphere begins to ________.
sink because it cools and contracts
A guyot is ________.
an extinct oceanic hot-spot volcano that has subsided below sea level
All other factors being equal, intrusive rocks that form deep within Earth ________ than intrusive rocks that cool near the surface.
are more felsic
