Earth’s Structure and Processes
What is Geology?



Geology: the study of planet Earth
A geologist studies the forces that make and shape planet Earth
They study the processes that create Earth’s features and search for clues about Earth’s
history
What forces cause Earth’s surface to change?
Two main forces:
1. Constructive forces: shape the surface by building up mountains and landmasses
What forces cause Earth’s surface to change?
2. Destructive forces: slowly wear away mountains, and eventually, every other feature on the surface
(weathering, erosion, etc)
What’s inside Earth?
•
Earth’s interior is made up of three main layers:
•
Crust
•
Mantle
•
Core
 Each layer has its own conditions and materials
How do you know what’s inside?


Geologists can learn about the interior of Earth by studying the paths of seismic waves
These are produced by earthquakes
Earth’s lithosphere is broken into about 20 pieces called tectonic plates
Layer
Crust
Mantle
Core
Relative Position
Outermost layer
Thinnest under oceans
Thickest under
continents
Crust and top part of
mantle make up the
lithosphere
Middle layer
Thickest layer
Top portion under
lithosphere is called the
asthenosphere
Inner layer
Consists of 2 partsouter core and inner
core
Density
Least dense layer
Oceanic crust is more
dense than continental
crust
Composition
Solid rock
Mostly oxygen and
silicon
Oceanic crust-basalt
Continental crustgranite
Density increases with
depth because of
increasing pressure
Hot softened rock
Contains iron and
magnesium
Heaviest material
Most dense layer
Mostly iron and nickel
Outer core – slow
flowing liquid
Inner core - solid
Earth’s Structure and Processes
What is Geology?



____________: the study of planet Earth
A _______________ studies the forces that ___________________________________________
They study the processes that create Earth’s ___________________ and search for clues about
_____________________________
What forces cause Earth’s surface to change?
Two main forces:
1. ___________________________ forces: shape the surface by ________________________
mountains and landmasses
What forces cause Earth’s surface to change?
2. _____________________________ forces: slowly ____________________mountains, and eventually,
every other feature on the surface (weathering, erosion, etc)
What’s inside Earth?
•
Earth’s interior is made up of three main layers:
•
________________
•
________________
•
________________
 Each layer has its own ____________________ and _____________________
How do you know what’s inside?


Geologists can learn about the interior of Earth by studying the paths of ___________________
These are produced by ____________________
Earth’s ______________________ is broken into about 20 pieces called _________________________
Layer
Relative Position
Density
Composition
Crust
 _______________
layer
 Thinnest under
__________
 Thickest under
_______________
 Crust and top part
of mantle make
up the
_____________
 __________ layer
 __________ layer
 Top portion under
lithosphere is
called the
_______________
 ________ layer
 Consists of 2
parts_____________
and
_______________
 Least _________
layer
 _________ crust
is more dense
than
______________
crust
 __________________
 Mostly ____________
and ___________
 Oceanic crust________
 Continental crust___________
Mantle
Core
 Density
 ___________________
______________
rock
because of
 Contains _______ and
increasing
___________________
_____________
 ______________  Mostly _______ and
material
___________
 Most _________  Outer core – slow
layer
flowing ___________
 Inner core __________