What is Earth Science?The study of the earth’s systems

and the interactions between these systems

Divided into 5 fields of study• Astronomy• Meteorology• Geology• Oceanography• Environmental Science

What are Earth’s Systems?

•Geosphere•Atmosphere•Hydrosphere•Biosphere

Geosphere

Everything from the crust to the center of the earth.

Geosphere

The Forces Within the Earth Plate Tectonics (Ch 17)

Earthquakes (Ch 19)Mountain Building ( Ch 20)

Volcanism (Ch 18)

In text turn to page 956• Observe the continents • Does the shapes & position of the continents

suggest they were once joined? Which Ones??

Early Observations• 1500’s a Abraham Ortelius Dutch

cartographer noticed the apparent fit of continents on either side of the Atlantic Ocean

• He proposed that N & S American was separated from Europe and Africa by earthquakes and floods…

• Referenced as creator of the modern atlas

20th Century • 1912 Alfred Wagner presented his

hypothesis that continents were slowly drifting around the Earth• Developed the continental drift theory

Continental Drift Theory• Earth’s continents had been joined as

a single landmass that broke apart and sent the continents adrift • Single Landmass supercontinent

named Pangaea • Pangaea Greek word means all the

Earth

Pangaea

• Break up about 200 million years ago.

• Observed: puzzle like fit.

• Evidence: rock, fossil and climate

Rock EvidencePredicted: When Pangaea broke apart large geologic structures such as mountain ranges

fractured during separationInvestigated: Areas of similar rock types on

opposite sides of the oceansView Figure 17.3 in TEXT p 470 Rock Layers in the Appalachian Mountains are identical to mountains in Greenland & Europe

Fossil Evidence• Predicted: Land animals such as Lystrasaurus

or Cynognathus could not have swum the great distances

• Investigated: Similar fossils from several different plants & animals found on widely separated continents

• Carbon dating of the fossils support the time frame of Pangaea breakup

• View Figure 17.3 in TEXT p 470

Climatic Evidence• Predicted: Fossils of plants like Glossopteris grew in

temperate climates and found all over the world

• Investigated: The area that separated these fossils is too large to have a single climate

• For example fossil record of the plant in Antarctica & South Africa and S American

• View Figure 17.3 in TEXT p 470

Climatic Evidence• Coal Deposits : Existence of beds in Antarctica Frozen climate once had tropical climate • Glacial Deposits : Found in parts of Africa,

India South America Locations of these continents too warm for ice

formation

Continental Drift Theory Flaws

• 1st What force could push large mass over great distances

• 2nd How the continents could move were through something solid like earth’s crust

• They questions were the reasons why Wegener’s theory was rejected until the 1950s