Unit 2: Interactions in the Physical Environment Flashcards
4 layers of the earth
Inner core, outer core, mantle, crust
Convection currents
Occurs in the mantle, the force moving the plates.
Divergent plate boundary
When 2 plates move apart. Commonly occurs along a mid-oceanic ridge. When this happens, both plates get larger. New areas of the crust are constantly being created this way. Most volcanoes occur along divergent plate boundaries.
Convergent plate boundary: continental meets oceanic
The heavier oceanic plate slides underneath the continental plate (subduction). Existing crust is recycled by subduction, which balances the new crust forming at divergent plate boundaries.
Convergent plate boundary: continental meets continental
2 continental plates run into each other, massive layers of rock are folded, broken, and forced upward by the immense pressures of the collision.
Transform plate boundary
Plates move in roughly parallel, but opposite directions. Plates are made neither larger nor smaller.
Precambrian era
- 4600 to 570
- Precambrian shields formed
- First multi-celled organisms
- First single-celled organisms
Paleozoic era
- 570 to 245
- Periods when large parts of North America are covered by shallow seas
- Appalachians formed
- Age of amphibians and fish
- First insects
- Large swamps (coal formed from this vegetation)
- First plants and animals appear on land
Mesozoic era
- 245 to 66
- Formation of Rocky Mountains begins
- Innuitian Mountains formed
- Shallow seas in the interior of North America at various times
- Age of reptiles
- First flowering plants
- First birds and mammals
Cenozoic era
- 66 to present day
- Ice sheets cover much of North America
- Continents take on their present shape
- Formation of Rocky Mountains completed
- Human beings develop
- Age of mammals
- Modern forms of live evolve
Igneous rock
Forms when magma/lava cools. Intrusive rocks cool underground and contain large crystals, while extrusive rocks cool above ground and contain tiny crystals.
Sedimentary rock
Created after millions of years of compaction and cementation of loose sediments. Sometimes contains deposits of fossil fuels.
Metamorphic rock
Transformed versions of igneous, sedimentary, or other metamorphic rocks. Occurs when rocks are exposed to great amounts of heat and pressure. Metamorphic versions of sedimentary rock are harder than the original.
Compaction
Occurs as loose sediments become tightly packed from drying or the weight of more layers on top.
Cementation
Sediments become cemented together by minerals deposited in between.
Erosional processes
Weathering, erosion, deposition
Weathering
The breaking down of rocks
Erosion
The moving of broken-up pieces of rock
Deposition
The building up of eroded materials in a new location
Forces involved in the erosional processes
Water, wind, glaciers, gravity
Glaciation
The process of ice advancing and covering large areas of land
Impact of glaciation
- Erosion: removal of materials, changes to drainage patterns
- Deposition: by ice (till plains, moraines), by meltwater (by moving water, by still water)
2 factors responsible for the appearance of all landforms in Canada
- The underlying geology
- The impact of glaciation
Number of landform regions in Canada
7