_____ of the water on earth is in the Oceans
_____ of earth's surface is covered by water
Average ocean depth is ________
Average temperature of ocean is _____
Deepest spot in the ocean is ______
Average age of oceanic crust is ________ years old. (Earth is thought to be 4.6 ______ years old).
65 million (4.6 million)
a) __-waves ( _____ waves) travel through....
b) __- waves ( _____ waves) travel through...-
a) ____ Waves
b) ____ Waves
- P- waves (primary waves) travels through solid AND liquid
- S- waves (shear waves) Travels through solid ONLY
- Love Waves (straight bottom of a heart ripple)
- Rayleigh Waves (circular motion)
What are Body waves?
Primary and shear waves
What are surface waves?
Love wves and Rayleigh Waves
If the Earth's interior had a _____ density, body waves would travel along a straight path.
If the density of the Earth's interior __________, body waves would travel along curved paths.
increased with depth
What is the principle of buoyancy?
objects will sink until is displaces a volume equal to the mass of the object.
Increasing temperature with Depth result....?
The physical transition from lithosphere to asthenosphere
Why does lithospheric crust "float" over the deformable ______?
Asthenosphere; because of the increasing temperature and pressure
Whose propoed the idea of Continental Drift in 1912 and what is it?.....evidence?
Alfred Wegner first proposed the idea of continental Drift and primary evidence for his theory has the matching shoreline patterns of many of the continents.
Who suggested that the continents were flund toward the equator by ________of the spinning earth.
Alfred Wegner, centrifugal force
________ in the ______ provides the driving force for continental drift.
________ was an idea proposed in 1960 to explain the features of the ocean floor. Explain it.
Seafloor spreading, It explained the development of the seafloor at the Mid-Atlantic Ridge. Convection currents in the mantle were proposed as the force that caused the ocean to grow and the continents to move.
The heat that drives the plates s generated by the ________ within Earth.
decay of radioactive elements
Divergent plate boundaries -
and its two crust including example.
This is also where ____ are formed
Boundaries between plates moving apart
- Divergent oceanic crust - the Mid-Atlantic Ridge
- Divergent continental crust - Rift Valley of East Africa
Divergent Plate Boundaries
(a) As the _______ began to crack, a _____ formed beneath the continent, and molten ________ from the ________ began to rise.
(b) As the _____continued to ______, the two new continents were separated by a growing_______. Volcanoes and earthquakes occur along the ____________, which is the _______. The East African Rift Valley currently resembles this stage.
- (a) lithosphere, rift, basalt, asthenosphere
- (b) rift, open, ocean basin, active rift area, mid-ocean ridge,
Convergent Plate Boundaries-
List and example for the three situations.
Where Oceanic Crust is _____.
Regions where plates are pushing together.
Oceanic crust toward continental crush - west coast of South american
Oceanic crust toward oceanic crust - occuring in the northern Pacific
- Continental crust toward continental crust - Himalayas
Transform fault boundaries is? and is a result of what?
Where two plates slide past one another.
Its a result of divergent seafloor spreading because it doesnt follow a smooth curve.
Evidence supporting the theory of Seafloor Spreading:
- 1) the rotation of the earth and convective circulation of the iron rich materia in the outer core drives our earth's magnetic field
- 2) this tilts the magnetic north pole 11o from the geographic north pole
- 3) The magnetic north pole wanders considerable over long time scales.
- 4) Upwelling mgma that forms the basaltic oceanic crust contains iron-bearing magnetite.
- 5) when these materials cool past the currie point they lock their orientation to the Earth's prevailing magnetic field.