Geologic History & Canada's Landform Regions - unit 2.1 review Flashcards
Name the 3 solid spheres and the 2 non-solid spheres of the earth
3 solid spheres - lithosphere, mesosphere, centrosphere
2 non-solid spheres - hydrosphere, asthenosphere
label each diagram with the layers of the earth
- a) Crust (lithosphere) / b) Mantle (mesosphere) / c) Outer core / d) Inner core
- a) Oceanic crust / b) Ocean / c) Continental d) Lithosphere / e) Lower mantle (semi-rigid) / f) Upper mantle = asthenosphere (flowing) / g) Upper mantle (rigid)
Who was the scientist who came up with the theory of Continental Drift?
Alfred Wegener
What did Alfred Wegener’s theory claim? (2 things)
1) 300 million years ago: all the earth’s land masses collided to form one continent called Pangea (meaning “all land”)
2) 200 million years ago Pangaea started to break up and the continent drifted in different locations to where they are today.
What was the first proof that led people to believe the continents were once connected? What were the other 3 proofs?
evidence #1: the jigsaw fit of the continents/ coastline fit
evidence #2: fossil correlation
evidence #3: geologic similarities
evidence #4: glaciation
Who was the scientist who came up with the theory of plate tectonics?
J. Tuzo Wilson
Explain the theory of plate tectonics?
-for over 4 billion years they have been moving around on the earth’s surface in a process called plate tectonics.
-tectonic plates are floating over a layer of hot rock several hundred kilometers below the earths surface.
-interactions along plate boundaries result in earthquakes, mountain building, and volcanoes
What force is responsible for moving tectonics in J. Tuzo Wilson’s theory?
Convection currents.
-formed from heat from deep within the earths crust
-made up of slow movement of magma in the mantle that carries heat from the interior of the earth to its surface.
-when plates move apart, magma from within the mantle rises to fill the open space and then cools forming a new crust
Why do volcanoes and earthquakes occur at plate boundaries?
-it is where plates move in relation to each other
-plates are moving in different speeds & directions
-movement causes friction that disrupts the earths crust
what are the 4 types of plate movements? draw & label a diagram with arrows to show each type of plate boundary.
- Divergent
-occurs when 2 plates move apart. this happens along a mid-ocean ridge - Convergent
- Transform
what type of plate boundaries form mountains?
convergent - when two continental plates meet, massive layers of rock are folded, broken, and forced upward by immense pressures of the collision
what type of plate boundary creates a fissure in the earth’s crust? what happens when a fissure occurs?
stress is created by convection currents in the mantle. if the rock is brittle or the forces cause the rock to move faster that it can bend, it will fracture.
they will provide pathways for fluids to flow
what is the definition of a volcano?
a place on earth’s surface where molten rock, gases and explosive debris erupt through the earth’s crust
what are the 3 phases of volcanic activity? Name and explain each. Active, dormant, extinct
Active: A volcano is active if it is erupting, or may erupt soon
Dormant: A dormant volcano is one that may have erupted before, but it is no longer erupting
Extinct: An extinct volcano is not erupting and will never erupt again.
what is the definition of an earthquake?
rapid shaking of the earth created by sudden movement of large sections of rock, natural hazards that occur when the earth’s tectonic plates move against each other.
how do earthquakes occur?
when plate tectonics move against each other
what are aftershocks?
-smaller ground shakes that occur after an earthquake in the same general area during the days to years following a larger event
what are seismic waves? what is the name of the device which measures seismic waves displayed on paper?
a wave of energy that is generated by an earthquake or other earth vibration and that travels within the earth or along its surface.
richer scale - used to identify the magnitude of an earthquake
seismograph - detects and records seismic waves
what is the richer scale? (2)
-a logarithmic scale created in 1935
-used to identify & measure the magnitude of an earthquake
explain what the pacific ring of fire is?
-an area encircling the pacific ocean
-makes a circle of high volcanic and seismic activity (earthquakes)
-most of the active volcanoes on earth are located here
what is a tsunami? how is a tsunami formed?
-a large wave or series of waves; occurs when an earthquake causes massive undersea crust movements and/or collapses displacing the water above.
-caused by earthquakes in the sea
label the features of a volcano and earthquake diagrams
what are the names of the 4 geologic eras of earth’s history in order from most recent to oldest? which one are we living in? which era is the longest?
4 geologic eras: cenozoic era (most recent 66 years) - mesozoic era (245 million to 66 million years ago) - paleozoic era (570 million to 245 million years ago) - precambrian era (4600 million to 570 million years ago)
-we are living in the cenozoic era
-the longest era is precambrian era
name one geologic event and biologic event for each era.
cenozoic:
biological - human beings develop
geologic - formation of the rocky mountains completed
mesozoic:
biological - first birds and mammals appear
geologic - formation of rocky mountains begin
paleozoic:
biological - periods when large parts of North America are covered by shallow seas
geologic - first plants and animals on land
precambrian:
biological - first single and multi-celled organisms
geologic - islands collide to form continents
