continental drift theory

The Continental Drift, is a theory that proposed that all of the continents were once a single land mass known as PANGAEA. This theory was proposed by ALFRED LOTHAR WEGENER

ALFRED WEGENER- A German Scientist, in the

year of 1912 who proposed Continental Drift Theory.

Evidence

Although, Wegener didn't have any proof, there was evidence discovered supporting the theory by several scientists. Unfortunately, the evidence was gathered after Wegner passed away. There are approximately five pieces of evidence that support the theory of the Continental Drift.

PANGAEA EVIDENCE

1. Jig saw puzzle of continents

PANGAEA EVIDENCE

2. The similar ancient animals and plant fossils, found on the edges of various continents.

fossil of a Glossopter

isFossil of a Mesosaur

fossil of a Cynognathu

s

Fossil of a Lystrosaur

us

PANGAEA EVIDENCE

This is a map of Pangaea, showing the continents connected and showing the matching fossils of plants and animals.

PANGAEA EVIDENCE

3. Identical rock sequences and age.- Basically meaning, various countries have identical rock sequences. For Example, South America and Africa have identical rock sequences, because they were joined when Pangaea existed.

PANGAEA EVIDENCE

4. North America and Europe having the same mountain ranges.- there have been mountain ranges found in North America and Europe that are identical, proving the theory.

PANGAEA EVIDENCE

5. The climatic conditions.- There have been glacial deposits founded in the tropics and coal founded in Antarctica. This supports the theory of the Continental Drift, because coal originates from tropical plants, which can only be founded in the tropics. Additionally glacial deposits can only come from Antarctica, proving the theory.

PANGAEA EVIDENCE

This photo shows the glacial deposits founded in various

continents

Although, this is the theory believed by many scientists today, many were skeptical about Wegener's theory during his period of time.

Many were skeptical, because he couldn't prove the theory of the Continental Drift, although he proposed the idea.

Furthermore, he couldn't prove the movement of the continents. However, after Wegner passed away, it was proven that the movement of the continents, resulted from the motion of crustal plates.

Seafloor Spreading provided insight to the mechanism for how the continents moved. The magma which pushes up at the mid-ocean ridge provides the new land pushing the plates, and the subduction zones gobble up the land on the other side of the plates.

The mechanism was convection currents!

Thirteen plate on the world

Pangaea about 200 million years ago, before it began breaking up. The southern portion of Pangaea

GONDWANA, and the northern portion LAURASIA.

As the seafloor spreads apart at a mid-ocean ridge, new seafloor is created.

Plate tectonic explainEarthquakes Mountains

volcanoes

Earthquakes and volcanoes occur mostly along or Earthquakes and volcanoes occur mostly along or near trenches and mid-ocean ridges...near trenches and mid-ocean ridges...

Continents look like they could be part of a giant jigsaw puzzle

Distribution of fossils of several organisms supported The theory that the continents were once joined together

Francis Bacon (1561-1626) first noted how coasts of Africa and South America fit.

Mesosaurus, a fresh water reptile that couldn’t swim across the open sea

Same rock patterns found in South America, India, Africa, Antarctica and Australia

Mountains in South America and Antarctica are believed to have formed as part of the same mountain chain.

Tropical plant remains (coal deposits) found in AntarcticaGlaciations in Africa, South America, India, and Australia during the same time

Deposits found in Antarctica.

Coal requires a warm, lush climate

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What’s Antarctica like today? ===>

Fossils of Glossopteris are found in Permian rocks of South Africa, India, Australia, South America, and Antarctica—all regions that were once part of Gondwanaland.

•No mechanism for movement of continents

•Wind and currents could possibly move fossils

•Theory was not accepted by scientists