Evidence for a Changing Evidence for a Changing EarthEarth

PART 1PART 1Chapter 1 Section 3 Drifting Continents

How does the earth How does the earth change?change?http://science.discovery.com/tv-shows/greatest-discoveries/videos/100-greatest-discoveries-continental-drift.htmvideo by Bill Nye 100 Greatest Discoveries.

Wegener’s PangaeaWegener’s Pangaea

http://www.platetectonics.com/book/page_7.asp

Evidence for Continental DriftGlossopteris fossils- woody

fern-like trees from 250 million years ago. Found across continents.

Evidence for Continental DriftLystrosaurus fossils-(meaning "shovel

lizard") Lystrosaurus was a heavily-built, mammal like reptile with a short, stubby tail. Instead of teeth it had two tusk-like fangs made of horn. It was a plant-eater about 3 feet (1 m) long and about 200 pounds. It lived in herds near lakes and swamps. Since fossils of Lystrosaurus had been found in South Africa, India, Europe, and Asia, finding Lystrosaurus fossils in Antartica was further evidence that the continents were once connected into one large continent.

Lystrosaurus

Evidence for Continental DriftMesosaurus fossils- Wegener found

Mesosaurus fossils in Africa and South America. It was a major piece of evidence to support his theory of continental drift. Since the Mesosaurus was a fresh water reptile, there was no way it could have swam across the Atlantic Ocean (which has salt water) to both continents. So it provided evidence that Africa and South America were at one point joined together.http://wiki.answers.com/Q/Where_did_Alfred_wegener_find_fossils_of_mesosaurus#ixzz1aVA2RgLd

Mesosaurus

Continental DriftContinental Drift http://www.youtube.com/watch?v=WaUk94AdXPA&feature=

related

http://www.youtube.com/watch?v=Cm5giPd5Uro

In 1910, Alfred Wegener proposed the theory of continental drift. He believed that the continents were drifting apart. He found evidence to prove his theory. But he could not answer one question. How were the continents moving? He thought they were plowing through the ocean crust. Other scientists knew this could not happen and so discredited his theory.

http://wgvu.pbslearningmedia.org/resource/ess05.sci.ess.earthsys.wegener1/plate-tectonics-the-scientist-behind-the-theory/Historical snapshot about Alfred Wegener.

Three pieces of Evidence for Three pieces of Evidence for Continental Drift TheoryContinental Drift Theory

1.

2.

3.

Alfred Wegener Song By The Amoeba Peoplehttp://www.youtube.com/watch?v

=T1-cES1Ekto&feature=related

Evidence for a Changing Evidence for a Changing EarthEarth

PART 2PART 2Chapter 1 Section 4 Sea-floor Spreading

Sea-floor SpreadingSea-floor SpreadingIn the 1960's scientists finally found

what was missing in Wegener's theory. Geologist Harry Hess finally found evidence that Wegener was right when mountains were discovered at the bottom of the ocean. Hess proposed his theory of sea-floor spreading as the answer to the mystery of continental drift. 

Discovery of Underwater Discovery of Underwater MountainsMountains

 The mid-ocean ridge is found throughout the oceans of the earth. This is a 50,000 mile chain of volcanic mountains in the middle of the ocean.

These mountains have a deep crack that runs through them. It is called a rift valley.

Sea-floor spreading happens here as molten magma from the mantle oozes up and forms new ocean floor spreading the plates apart. It is a slow, regular process. There are no explosive bursts like volcanic eruptions on land.

Mid-Ocean RidgeMid-Ocean Ridge“Sea Floor Spreading with Bill Nye”http://www.youtube.com/watch?v=GyMLlLxbfa4&feature=related

Evidence for Sea-floor Evidence for Sea-floor SpreadingSpreadingDuring WWII Geologist Harry Hess worked on a ship that had sonar. They mapped the ocean floor and discovered the “Mid-Atlantic Ridge”. Prior to this all scientists believed the Oceans floor was flat and barren.

Evidence for Sea-floor Evidence for Sea-floor SpreadingSpreadingThe mid-ocean ridges occur along

plate boundaries that are separating (diverging).

Rocks that form from molten rock , called “Pillow Lava” were discovered along the mid-ocean ridge by the submersible submarine named Alvin.

Evidence for Sea-floor Evidence for Sea-floor SpreadingSpreadingCore samples drilled and collected

from the Atlantic ocean floor showed that the sediment was thinner near the mid-ocean ridges and the age of the rock was younger meaning the ocean floor was younger at the mid-ocean ridge.

Core Sampling ModelCore Sampling ModelUse the straw at your group’s station

and carefully push it down into the cup on your table. ONLY ONE TIME! BE CAREFUL. DO NOT TIP OVER!!

Put your finger over the top and very gently and slowly pull up a core sample.

Each person should draw a diagram of your sample.

Question: What did scientists learn from core samples to support the theory of sea-floor spreading?

Evidence for Sea-floor Evidence for Sea-floor SpreadingSpreadingThose core

samples also showed a record of magnetic reversals. The rocks particles were aligned differently as you moved out away from the mid-ocean ridge on either side showing a pattern of changes.

http://mail.colonial.net/~hkaiter/ContinentalDrift.html

Mid Ocean Ridge Mid Ocean Ridge FormationFormation

http://www.mysciencebox.org/files/images/seafloor_animation.gif

http://wgvu.pbslearningmedia.org/resource/ess05.sci.ess.earthsys.wegener2/plate-tectonics-further-evidence/ WATCH THIS!

Evidence for a Changing Evidence for a Changing EarthEarth

PART 3PART 3Chapter 1 Section 5

Plate TectonicsPlate Tectonics http://wgvu.pbslearningmedia.org/resource/ess05.sci.ess.ea

rthsys.plateintro/plate-tectonics-an-introduction/  http://wgvu.pbslearningmedia.org/resource/ess05.sci.ess.ea

rthsys.boundaries/tectonic-plates-and-plate-boundaries/ Look at the plates!

Lithospheric Plates of the Lithospheric Plates of the EarthEarthThe Earth’s lithosphere is broken

into plates that are constantly moving and changing the surface of the Earth.

http://dreamtigers.wordpress.com/2011/05/11/plate-tectonic-metaphor-illustrations-cmu/

The Major PlatesThe Major PlatesList the names of the platesList the names of the plates

2-D Earth 3-D EarthLooking at the Earth from a 2-D

map can be misconceiving. Check out the site below!

http://www.classzone.com/books/earth_science/terc/content/investigations/es0301/es0301page03.cfm

What is Plate Tectonics?What is Plate Tectonics?The term plate tectonics refers to

how the Earth's surface is made up of plates. In geology, a plate is a large slab of rock, while tectonics is a word of Greek origin meaning "to build.“

Plate Tectonics is the current theory that explains how the surface of the Earth is broken into plates that are slowly but constantly forming, subducting and changing to create the features of the Earth’s surface.

Evidence for Plate Evidence for Plate TectonicsTectonicsThe theories of continental drift and sea-floor spreading

gave a basis for the discovery of the plates. However further evidence from the locations of earthquakes and volcanoes helped to map their boundaries.

Evidence for Plate TectonicsEvidence for Plate Tectonics

TIME LINE FOR THE TIME LINE FOR THE DEVELOPMENT OF THE DEVELOPMENT OF THE THEORY OF PLATE THEORY OF PLATE TECTONICSTECTONICShttp://www.britannica.com/EBche

cked/topic/463912/plate-tectonics/301055/Time-line-of-the-development-of-the-theory-of-plate-tectonics

Have to join to see this! UGH!

How do the Plates Move?How do the Plates Move?Geologists believe that

convection currents in the mantle provide the force that moves the plates.

http://www.windows2universe.org/earth/interior/how_plates_move.html How do the plates move?

http://www.youtube.com/watch?v=ctoMRrUwBwI New evidence for movement of the plates. Time 1:15

Movement of the PlatesMovement of the PlatesHow do scientist know that the continents are

moving today?http://www.pbs.org/wgbh/nova/ice/continents/Have you ever rode bumper cars? The plates are

moving around like this crashing into each other, moving away from each other, or sliding past each other. They all move at different speeds, anywhere from a couple of millimeters to several centimeters per year. Overall they move very slowly. The place where the two plates meet is called a plate boundary. There are three types of boundaries. Faults occur along these boundaries where the crust slips and fractures.

Diverging Plate Diverging Plate BoundariesBoundaries

Diverging boundaries occur where plates are pulling apart. The mid-ocean ridge is the most common divergent boundary. A rift valley forms where these occur on land.

http://wdict.net/word/divergent+boundary/

The Great Rift ValleyThe Great Rift ValleyThe plates

can separate across a continent too!

http://seeker401.files.wordpress.com/2011/01/image004.jpg

The Earth’s Surface The Earth’s Surface SeparatesSeparates

http://www.sciencephoto.com/media/167053/enlarge

http://science.discovery.com/tv-shows/when-earth-erupts/videos/african-rift.htm watch this series of 4 short videos about the rift valley.

Converging Plate Converging Plate BoundariesBoundarieshttp://www.pbs.org/wgbh/nova/everest/

earth/shock.htmlWatch this to see how the Himalayan

Mountains are forming.Converging boundaries can occur where

two continents are smashing into one another and form mountains.

http://dreamtigers.wordpress.com/2011/05/11/plate-tectonic-metaphor-illustrations-cmu/

Converging Plate Converging Plate BoundarBoundariesies

Converging plates also occur at subduction zones where the ocean plates dive below the continents forming deep-ocean trenches.

Transform Plate Transform Plate BoundariesBoundaries

Transform boundaries happen where plates are sliding past each other. One of the most famous is in California, the San Andreas fault, where the edge of California is shearing off to the North.

http://www.cotf.edu/ete/modules/msese/earthsysflr/plates1.html

Hot SpotsHot SpotsHot Spots are places where the

Mantle reaches up close to the surface of the crust either near boundaries or in the center of plates. The Hawaiian Islands are formed this way, as well as places like Yellowstone National Park.

http://www.geology.sdsu.edu/how_volcanoes_work/intraplvolc_page.html What are hot spots?

Hot Spots around the Hot Spots around the EarthEarth

The Search for New Evidence The Search for New Evidence Continues!Continues!Trip to the bottom of the Mariana

Trench, the deepest place in our oceans.

http://en.wikipedia.org/wiki/Mariana_Trench Information here.

http://www.youtube.com/watch?v=Y2tm40uMhDI Time 2:05 Released March 2012 National Geographichttp://www.youtube.com/watch?v=RxUZM-

cLtGg&feature=player_embedded Video from Oct. 2011 showing jellyfish at bottom of trench and Xenophyophores,giant single-celled sea creatures that can be 4 inches wide.

Life at the bottom of Life at the bottom of a Mid-ocean Ridgea Mid-ocean Ridgehttp://wgvu.pbslearningmedia.org/resource/

tdc02.sci.ess.earthsys.deepseavents/deep-sea-vents-and-lifes-origins/ “Deep Sea Vents and Life’s Origins”Time 4 min.

http://wgvu.pbslearningmedia.org/resource/nsn09.sci.life.eco.seafloor/exploring-the-arctic-seafloor/ Exploring the Arctic sea floor.

http://wgvu.pbslearningmedia.org/resource/ipy09.sci.life.eco.scini/studying-the-antarctic-sea-floor/ Exploring the Antarctic sea floor using a ROV called SCINI.