Striation – linear grooves formed in the surface of some minerals as they grow.

Plate Tectonics

Geologic Time

4600

543

248

65

The Prune Effect - 1800s - (failed attempt 1)

The molten Earth cools and contracts

The crust wrinkles and crumples

Mountains form

What about rift valleys?

What about shape and position of the continents?

Rift Valley

The Expanding Earth – (failed attempt 2)

20th century - radioactive decay

Land masses are ripped apart

Explains the continents

What about the mountains?

- An idea before its time

- Alfred Wegener 1915

- Processor to plate tectonics

Continental Drift

Pangaea - supercontinent

Fragmented and floated around

Pangaea 200 million years ago

Super Continent

Lines of Evidence

•Matching Coastlines

•Matching Geology

•Glacial Deposits

•Fossil Evidence

•Apparent Polar Wandering

Matching

Coatlines

Where is the coastline?

Matching

Geology

The Collision

The Separation

Glacial Deposits

Striations

Fossil Evidence

Glossopteris

Mesosaurus - links South America and Africa during the late Paleozoic and early Mesozoic eras.

Apparent Polar Wandering

A study by S. K. Runcorn in the 1950s, indicated that the magnetic north pole had apparently moved over the last 500 million years, from Hawaii to its present location.

All the parts are in place,

but 1.

How are the continents moving?

The Revolution Begins

early 1960s

RingOf

Fire

Discovery of Midoceanic Ridge

Detailed sea-floor mapping

Harry Hess - essay in geopoetry

* Sea-floor spreading hypothesis

Paleomagnetism

Youngest rock in the center

Unifying Theory - Plate Tectonics

Tectonic cycle- deals with the movement and interactions of the lithospheric plates.

Seafloor Spreading and Plate Boundaries

Plate Boudaries / MarginsDivergent Plate Bounderies

1. continental - rift valleys

Divergent Plate Boundaries

2. ocean - midoceanic ridge / spreading sea floor

Transform Plate Bounderies

San Andreas Fault

Convergent Plate Bounderies

Oceanic - Continental

Oceanic - Oceanic

Continental - Continental

Andes Mountains

Japan, Philippines

Himalaya Mountains

West Coast of United States

Earthquakes, Volcanoes, and Plate Boundaries

Benioff ZoneAssociated with Subduction

How old is the ocean floor?

Driving Mechanism - convection currents