Geological HistoryGeological History

EarthEarth’’s Formations Formation• http://www.youtube.com/watch?

v=QDqskltCixA

• Watch this video FIRST, and take a few notes on the formation of Earth.

• Then after the video you will have 3-4 minutes to write down a paragraph 4-5 sentences long that summarizes the formation of Earth…

• I will pick 3 people to read.

First, What is Earth Like Inside?First, What is Earth Like Inside?

• Write down a diagram in your notes and describe the layers of the Earth…

• Describe if each layer is liquid, solid, hot, cold…ect.

What is Continental Drift?What is Continental Drift?• Proposed by Wegener-1915

• Theory that states that all the plates move and the continents were once a single landmass which split apart…Pangaea

• Precursor to theory of plate tectonics

Evidence for Plate TectonicsEvidence for Plate Tectonics

• What 3 pieces of evidence do you think we have for continental drift?

• List them in your notes.

Evidence 1Evidence 1

• All of the continents fit together like a puzzle

Evidence 2-FossilsEvidence 2-Fossils• Identical Fossils were located directly opposite on

widely spaced apart continents

Evidence 3-Rock TypeEvidence 3-Rock Type

• Similar rock types, age and structure found on different continents

• Ex:Appalachians and mountains in Scotland/Scandi-navia

Why do plates Why do plates ““floatfloat”” and what and what do they float on?do they float on?

• Isostasy- The crust floats on the mantle since the crust is less dense.

• The heavier the crust, the more it will push on the mantle

• Mantle is not “liquid” like we think of it…it flows like glass.

Isostasy ExamplesIsostasy Examples• In areas formerly covered by ice sheets (around

the Baltic Sea and Hudson Bay, for example), sea cliffs and beach ridges are now found nearly 300 m (1000 feet) above sea level!

• Why?

How do plates push apart?How do plates push apart?

• http://www.youutbe.com/watch?v=CFtce8bYJO8• Convection: http://www.youtube.com/watch?

v=ryrXAGY1dmE• Sea Floor Spreading- Magma pushes up in a ridge

on the ocean floor and creates new crust—pushing the crust apart

• In ocean trenches the crust moves down and melts

Proof of Seafloor SpreadingProof of Seafloor Spreading• Paleomagnetism-

– The Earth’s magnetic field has reversed throughout history.

– The element iron in the rocks in the ocean crust orients to the magnetic field as it is forming.

– Distinct patterns show the rock has the same orientation as it spreads apart.

Before the Bell…Before the Bell…

• Take out your Notes from Friday • Take out your notes from the Red Book• Answer this question in your

– What is the theory of plate tectonics…be specific…and what proof do we have? What drives plate tectonics…

– What are the 2 types of plates– What are the 3 types of plate movements– What are the 7 plate boundary situations and

features?

Results of Plate MovementResults of Plate Movement• Earthquakes- (this video puts it all

together!)https://www.youtube.com/watch?v=cavq2HFBa-U

• Current World Earth Quakes (Google Earth)-• Tsunami Animation-

http://www.youtube.com/watch?v=4Xebwzb3dDE• Tsunami Footage-

http://www.youtube.com/watch?v=RDOuwMj7Xzo• https://www.youtube.com/watch?v=w3AdFjklR50