Mountain Formation

1

• Mountain Formation Plate Tectonics

2
Continental Margins

• Continental margins are the boundaries where
  oceanic crust and continental crust meet (this is
  not always a plate boundary)
• There are 2 types of margins
• ACTIVE
• PASSIVE

3
Active continental margins

• occur along plate boundaries where the plates are
  moving (active)
• Earthquakes, volcanoes, and mountain formation
  all occur along active continental margins
• The subduction of the Nazca plate under the South
  American plate is an active continental margin
  (the Andes Mountains are formed here)

4
(No Transcript)
5
(No Transcript)
6
Passive continental margins

• Do Not occur along plate boundaries
• (no movement passive)
• major geologic activity along these margins is
  the erosion deposition of sediment
• The east coast of the United States is a passive
  continental margin

7
(No Transcript)
8
(No Transcript)
9
Mountain Formation by Collisions
10
Oceanic - Continental Crust

• oceanic crust subducts under the continental
  crust (remember, oceanic is more dense)
• This subduction causes rock layers to be pushed
  upward, forming mountains along the coastline
• Magma is also forced upward, sometimes causing
  the mountains that are forming to become volcanic
  (ex. the Andes Mountains along the coast of South
  America)

11
Collisions of two continents

• Since the continental crust is too light to
  subduct, they collide and crumble along the
  edges, and push upward (uplift)
• The Himalayan Mountains, with Mt. Everest, are
  formed by the Indian plate and the Eurasian plate
  colliding
• Mt. Everest is still getting higher!

12
(No Transcript)
13
Surface Features with Mountain Formation

• The Earths crust usually moves along a break or
  crack called a fault (a crack in the crust with
  no movement is called a joint)
• There are three main types of faults
• Normal
• Reverse
• Strike-Slip

14
(No Transcript)
15
(No Transcript)
16
Folding

• Layers of rocks can be folded as collisions occur
  (just like if you push the edges of a piece of
  paper together)
• If the layers fold upward, it is called an
  anticline (the upward folds form the outline of
  the letter A)
• If the layers fold downward, it is called a
  syncline (think of where you go if you sin) ?

17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
(No Transcript)