Which of the following statements are true: 1. continental crust has an average density of 2.7 g/cm3 2. continental crust is 5 - 10 km thick 3. p-waves travel slower through continental crust than through oceanic crust
2 and 3
1 and 3
1 and 2
all 3 statements are true
e. all 3 statements are false
what is the approximate radius of the earth:
64 km
640,000 km
640 km
64,000 km
6,400 km
choose the correct sequence of features of a passive continental margin from the continents towards the ocean:
none of the above
continental rise, continental shelf, continental slope, ocean trench
continental slope, continental shelf, continental rise, ocean trench
continental slope, continental shelf, continental rise, abyssal plain
continental shelf, continental slope, ocean trench, abyssal plain
which type of plate tectonic boundary forms a magmatic arc?
subduction zones
transform boundaries
divergent boundaries
which features are parallel to the mid-ocean ridge:
none of the above
both of the above
paleomagnetic stripes
transform fracture zones
which features are parallel to the mid-ocean ridge:
none of the above
both of the above
paleomagnetic stripes
transform fracture zones
the crust is thicker than the lithosphere.
false
true
due to subduction, the oldest seafloor on earth is not more than about:
200 million years old
2 million years old
2 billion years old
20 million years old
which type of plate tectonic boundary has no volcanic activity?
transform boundaries
divergent boundaries
subduction zones
which of the following are often found at the base of submarine canyons on the seafloor:
the continental shelf
ocean trenches
abyssal fans
atolls
coral reefs
which boundary is referred to as the mohorovicic discontinuity (or moho):
crust - upper mantle
none of the above
lithosphere - asthenosphere
outer core - inner core
upper mantle - lower mantle