General Oceanography Exam 1: Earth Formation and Structure

What is the nebular hypothesis?

• formed from nebula: interstellar cloud of gases (H, He, and other heavier elements)

• flat disk shape with protosun at center

• gravity pulls molecules to center

• proto planets form from accretion of minerals and rock particles clumping together

How was proto-earth formed?

Density separation of elements, created layers of the earth, with metals (Fe and Ni) sinking to center and molten rock (Ai, Si, Mg) forming primitive crust

Layers of Earth Defined by chemical composition

1. crust

2. mantle

3. core

Layers of earth defined by physical properties

1. Lithosphere

2. asthenosphere

3. mesosphere

4. outer core

5. inner core

Core contains ___ & ____

Fe and Ni

The crust contains ___, ___, ___, ___,

Al, Si, O, Mg

The mantle contains

Si, O, Mg, Fe

Density stratification is based on ____

atomic mass

melting point varies with ____ & ____

chemical composition, pressure

Lithospheric plate is made up of ___, ___ & ___

upper mantle, continental crust, and oceanic crust

Isostasy

the state of balance between the Earth’s crust and the mantle. Rigid outer layer floats on softer mantle below