Week 2 Flashcards
Internal Structure of the Earth
The Earth is made up of geochemical and geophysical layers
Starting from the center, the layers of the Earth are:
Inner Core
Outer Core
Mesosphere
Asthenosphere
Lithosphere
Inner Core
Super Hot
Solid Metal
Iron and Nickel
Outer Core
Very Hot
Liquid Metal
Iron and nickel
Mesosphere
Hot
Solid Rock
Dense rich in heavy minerals
Asthenosphere
Hot
Semi Molten Rock
Soft Plastic
Lithoshpere
Cold
Brittle Rock
Solid Shell
Earth’s Internal Heat
Estimates of the Earth’s core temperature are ~7500°C; that’s 1000°C more than the surface of the Sun
Kinetic Energy
Other sources of Earths heat include:
Radioactivity
Core Formation
Tidal Energy
Heat from Radioactivity
The radioactive decay of certain ions within the Earth can release heat
Heat from Core Formation
As the molten interior of the Earth differentiated, material moving up or down based on buoyancy could release heat, either due to decompression or a chemical reaction
Heat from Dissipation of Tidal Energy
The motion of the Moon around the Earth drives tides, both in the oceans and molten asthenosphere. The motion of tides within the asthenosphere effectively brakes the rotation of the Earth, causing heat to be released
Continental Drift
- First formalized by Alfred Wegener in 1912, the idea of continental drift was radical and revolutionary
- Not many people could believe the landmasses had moved around, and were continuing to move under their feet
- The jig-saw puzzle-fit of the continents on the globe; and,
- Correlation of plant and animal fossils across the continents.
- Still, few immediately accepted Wegener’s proposal, waiting for more evidence
Convergent Boundary
Tectonic plates are colliding, often forcing more dense crust underneath less dense crust; reflects compressional stress of crustal rocks
Divergent Boundary
Tectonic plates are moving apart, with new Basaltic crust forming at mid-ocean ridges, creating extensional stress
