Marine Science structure of Earth notes

1. Structure of the
Earth

2. Earth Basics:
Earth is unique because it is the only planet:
a) With liquid water on surface
b) With oxygen in the atmosphere in such a
large proportion
c) That supports life

3. Basic Facts:
1. 4.55 billion years old
2. Made mostly of rock
3. 71% of surface covered with water
4. Slightly flattened sphere
5. Rotates on its axis

4. Layers of the Earth
 Crust
 Mantle
 Core

5. How do we know about Earth’s
interior?
 Deepest hole only 12
km deep (6,400 km to
go) before it was too
hot to drill (356
degrees F)
 Used evidence from
seismic waves

6. Crust:
 Thin, solid outermost layer of the Earth that
makes up less than 1% of the volume of the
Earth
 Two Types of Crust:
 Oceanic
 Continental

7. Mantle:
 Layer of “solid-ish” rock located between the
crust and the core
 able to move through convection currents
 denser than the crust
 makes up 2/3 of the mass of the Earth

8. Mohorovicic Discontinuity
a.k.a.: Moho
 Layer/border between the crust and the
mantle

9. Lithosphere vs. Asthenosphere
 In terms of plate tectonics rather than “spheres of the
Earth”
 Lithosphere – the crust and rocky portion of the mantle
that make up tectonic plates
 Asthenosphere – plastic portion of the mantle that
moves via convection currents

10. Core:
 Central part of the Earth below the mantle;
iron-nickel alloy
 Two Parts:
 Outer Core – Liquid
 Inner Core - Solid

11. Core Temperature
 Heat is both residual from the formation of the
Earth and from energy due to the abundance
of radioactive materials

12. General Trends
 As you head towards the center of the Earth
 Temperature Increases
 Density Increases

13. Magnetism:
 The Earth has a magnetic North Pole and a
magnetic South Pole that creates a magnetic
field around it

14. Gravity:
 The force of attraction that exists between all
objects, the bigger and closer the object is,
the stronger the force of gravity