Lecture 5- Marine Geology 2 Flashcards
Pangaea
1
Q
Pangaea
A
the supercontinent that split apart to form the present-day configuration
2
Q
Wilson Rock Cycle
A
- process in which continents have repeatedly collided and broken apart
- happened even before Pangaea
3
Q
divergent boundaries occur between
A
- ocean and ocean
- continent and continent
4
Q
convergent boundaries occur between
A
- ocean and ocean
- ocean and continent
- continent and continent
5
Q
3 plate boundaries
A
- transform
- divergent
- convergent
6
Q
earth’s 2 types of crust
A
- oceanic
- continental
7
Q
oceanic crust
A
- thin (5 km)
- more density so floats deeper in the mantle
- consists mostly of basalt
8
Q
continental crust
A
- thick (70 km)
- less dense so they float higher in the mantle
- consists mostly of granite
9
Q
divergent boundaries
A
- occur where plates are moving apart
- most of these boundaries are mid-ocean ridges and less commonly, continental rifts
10
Q
examples of new divergent boundary
A
East Africa rift zone
11
Q
example of mature divergent boundary
A
mid-ocean ridges
12
Q
hydrothermal vent systems
A
found at mid-ocean ridge spreading centers
13
Q
continental boundary: ocean and continental
A
- ocean is more dense so it subducts and is pushed back down into the mantle
- generates deep ocean trenches and explosive volcanoes
14
Q
examples of ocean crust colliding with continents
A
- North Cascade Mountains
- Andes Mountains
- Mt. Saint Helens (volcano)
15
Q
continental boundary: oceanic and oceanic
A
- the plate that gets subducted is the one furthest from its spreading center
- deep oceanic trench (sometimes filled with sediment)
- older, colder, and more dense subducts
