Continental Drift/Geosphere Flashcards
The layers of the geosphere
- crust
- mantle
- outer core
- inner core
define Geosphere
part of the earth that is rock and is broken up into 4 parts
Crust
Thin layer 5-70 km thick
Mantle
- semisolid
- top is viscous
- 1,802 miles
Outcore
- made of iron and nickel
- molten metals and is liquid
Inner core
a hot solid metal ball
Lithosphere
- the crust and upper mantle
- interacts with each other to move plates
Plate tectonics in relation to the lithosphere
- because of the heat from the core it is divided into 10 major tectonic plates that move 2-15 cm each year
Who proposed the Continental Drift theory and what was problem and his findings?
Alfred Wegener
- it was missing the lithosphere
- studied earthquakes, theorized Pangaea and that the crust moved like an iceberg
Types of Boundaries
- Divergent
- Convergent
- Transform
*Properties at and of Divergent boundaries
- The asthenosphere pushes magma that becomes new land
- They are constructive
- Form mid-ocean ridges and hydrothermal vents
- Sea floor spreads
(*can also form abyssal plains on either side of the mid-ocean ridge)
*Transform Boundary and features
- Neutral (no land made or destroyed)
- Great seismic activity earthquakes and tsunamis
- Abyssal Plains
- Faults are formed
Types of convergent boundries
- Continental—> continental
- Continental —> Oceanic (destructive)
- Oceanic —> Oceanic (destructive)
Continental—> continental
- Neutral
- creates mountain ranges and very shallow earth movement
Continental —> Oceanic
- Destructive
- Oceanic plates are denser so goes under
- creates trenches and volcanoes (wayy inland)
- When the oceanic plate goes under it is subduction
Oceanic —> Oceanic
- older is denser and will go under
- creates island arcs
Describe the continental drift theory
continents move slowly over time
Evidence:
- similar species of plants and animals
- mountain range line up
- age of rock is the same
- fit together like puzzle pieces
Earth’s crust is controlled by…
the asthenosphere
through a process known as convention currents
Convection Currents key points
- Depends on density
- As the rock moves closer to the core, it warms up
- Heat causes the rock to become more liquidy and less dense, therefore rises
- As it rises it pushes against the plate and begins to cool and become more dense
- Once it cools to a certain temp, the rock begins to sink and the cycle starts again
Paleomagnetism
iron orients different directions
symmetrical banding supports seafloor spreading
(origin around mid-ocean ridges)
supports theory of plate tectonics
Earthquake
a sudden release of energy inside the earth that creates seismic waves (caused by movement of tectonic plates or volcanic activity)
- pressure from plate movement builds until there is slippage that releases stored potential energy
- energy moves though the lithosphere causing earthquakes
makeup of Oceanic crust
basaltic rocks with iron and magnesium
Theory of plate tectonics
Sections of Earth’s crust (plates) are in movement over the fluid mantle causing earthquakes and volcanoes at the borders of these plates
- the lithosphere is broken into sections called tectonic plates
- paleomagnetism
What is the strongest evidence supporting seabed spreading and plate tectonics?
paleomagnetism stripes direction
