Evidence of Plate Tectonics

Grade 8 Science Understanding Earth's Moving Continents

What do you notice about the continents?

Look at a world map Do any continents seem like they could fit together like puzzle pieces? What might this tell us about Earth's history?

Meet Alfred Wegener

German meteorologist and geologist Proposed continental drift theory in 1912 Suggested all continents were once joined in a supercontinent Called this ancient landmass 'Pangaea'

Pangaea: The Supercontinent

Evidence #1: Continental Fit

Coastlines of continents match like puzzle pieces South America and Africa fit together almost perfectly Other continents also show matching edges This suggests they were once connected

Evidence #2: Fossil Matches

Identical fossils found on different continents Mesosaurus fossils in South America and Africa Glossopteris plant fossils across multiple continents These organisms couldn't swim across oceans

Evidence #3: Rock and Mountain Matches

{"left":"Mountain ranges line up across continents\nAppalachian Mountains continue in Scotland and Scandinavia","right":"Same rock types and ages found on different continents\nGeological formations tell the same story"}

Evidence #4: Ancient Climate Clues

Glacial deposits found in warm regions today Coal deposits in Antarctica suggest tropical past Desert rock formations in wet climates Climate evidence shows continents moved through different zones

Modern Evidence: Sea-Floor Spreading

Mid-ocean ridges create new ocean floor Magnetic patterns in ocean floor rocks Ocean trenches where old floor sinks down This process moves the continents

Plate Tectonics Detective

Work in pairs to examine evidence cards Match fossil, rock, and climate evidence to continental positions Create a timeline of how continents moved Present your findings to the class