Theories of Geological Evolution

Theories of Geological Evolution

First StopCatastrophismHow is it possible to explain the worldaround you, without science?

Until the 1700s, most Europeans thought that a Biblical Flood played a major role in shaping the Earth's surface.

Catastrophism – the theory that Earth’s features are

mostly accounted for by violent, large- scale events that occurred in a

relatively short amount of time.

Second StopUniformitarianismIn the 1785 a new theorywas proposed by James Hutton, called Uniformitarianism.Charles Lyell expanded on this theory and wrote “Principals of Geology.”

Uniformitarianism – the theory that Earth’s features are mostly accounted for by

gradual, small-scale processes that occurred over long periods of time.

“The present is the key to the past.”

Notes1st theory – Catastrophism Earth shaped by catastrophes

2nd theory – UniformitarianismEarth shaped gradually by constant geologic processes

3rd theory – Continental DriftContinents were once connected and then drifted apart

4th theory – Plate Tectonics Convection seafloor spreading push and pull of

Earth’s plates

The Rise and Fall of a theory…and how it was saved changed.

Using 4 lines of evidence, Wegener was able to identify that the

continents were onceassembled asPangaea.

Third StopContinental Drift

NAME the Evidence

Fourth Stop ---- Final StopPlate Tectonics

Solving the mystery of Drifting Continents.

Harry Hess

With the person next to you:

1. Review your guided notes and list all of the evidences used in the theory of plate tectonics.

2. Draw a model of seafloor spreading and include the following aspects

◦ Mid-ocean ridge (MOR)◦ 2 lithospheric plates, include your crusts◦ 2 Convection Currents