Geological History

Earth’s Formation Ahttp:// A 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? 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? 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 Tectonics What 3 pieces of evidence do you think we have for continental drift? List them in your notes.

Evidence 1 All of the continents fit together like a puzzle

Evidence 2-Fossils Identical Fossils were located directly opposite on widely spaced apart continents

Evidence 3-Rock Type Similar rock types, age and structure found on different continents Ex:Appalachians and mountains in Scotland/Scandi- navia

Why do plates “float” and what 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 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? Convection: 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 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… 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 Movement Earthquakes- (this video puts it all together!) Ba-Uhttps:// Ba-U Current World Earth Quakes (Google Earth)- Tsunami Animation- Tsunami Footage