WHAT TO KNOW LIST, GEOLOGY 100
EXAM I – WEDNESDAY, February 6
explain the data/ observations with a hypothesis, test the hypothesis, confirm by making
Remnant of supernova ex) Crab Nebula in Taurus
•Explosion of a dying star
•Nuclear reactions create elements heavier than iron
•Eject large quantities of matter that form new nebulae
Dust particles collide and stick together from a nebula
Supernova to nebula to solar system
Formation of the solar system
The nebula condenses into a swirling disc, with a central ball surrounded by rings.
The ball at the center grows dense and hot enough for fusion reactions to begin. It becomes the Sun. Dust (solid
particles) condenses in the rings.
Dust particles collide and stick together, forming
Gravity reshapes the proto-Earth into a sphere. The interior of the Earth separates into
a core and mantle.
Forming the planets from planetesimals: Planetesimals grow by continuous collisions. Gradually, an irregularly
shaped proto-Earth develops. The interior heats up and becomes soft.
Soon after Earth forms, a small planet collides with it, blasting debris that forms a ring around the Earth.
The Moon forms from the ring of debris.
Eventually, the atmosphere develops from volcanic gases. When the Earth becomes cool enough, moisture condenses
and rains to create the oceans
•Estimated age of the Earth is 4.57 billion years
Differentiation of the Earth
•Denser materials moved to the center and lighter materials rose to the top
•Gases escaped from the interior, forming the early ocean and atmosphere
Types of igneous silicate rocks
•Silicic Rocks – high silica, low iron & magnesium; Granite
•Mafic Rocks – low silica, high iron and magnesium; Basalt and Gabbro
•Ultramafic Rocks – very low silica, very high iron and magnesium; Peridotite
•Variety of rock types, but overall is silicic - intermediate
•35 – 40 km thick
•7 – 10 km thick
•Denser than continental crust
Structure of Earth's interior (crust, mantle, lithosphere, asthenosphere, Moho, core, etc.)
(Primary Waves) – travel through solids and liquids
(Secondary Waves) – travel through solids but NOT liquids; travel slower than P waves
P waves bend at the core-mantle boundary because wave velocities slow down
P waves reflect off a boundary within the core
S waves don’t pass through the core at all
The outer core must be liquid
See graph 2
Earth's magnetic field – how it is generated, paleomagnetism, apparent polar-wander paths, magnetic reversals