Plate tectonic theory provides an explanation for several major physical geography events and landforms. So, what is it?
The theory has only really been around since the 1960s with deep sea exploration and analysis of the mid-Atlantic Ridge.
The movement of the continents and the theory of ‘Continental Drift’ was first raised by Alfred Wegener in 1912, with the evidence of fossils and shapes of coastlines being examined.
Evidence for Continental Drift Theory
More recently, plate tectonics has used the ideas of shifting landmasses with the tectonic plate boundaries to project past and future alignments of the continents, plus all of the violent earth processes that occur along the way.
How about the Earth 250 million years from now? What might it look like? Pangaea Ultima perhaps?
Pangaea Ultima?
NASA has a fascinating site exploring these far-future projections: http://science.nasa.gov/science-news/science-at-nasa/2000/ast06oct_1/
So, what happens at the plate boundaries? You could ask the Geology Kitchen for some answers!
Boundaries can be divergent (moving apart – also known as ‘constructive’ boundaries). These cause volcanic activity and often occur under the ocean, leading to sea-floor spreading.
Boundaries can also be convergent (moving together – also known as ‘destructive’ boundaries). These usually occur where one part of the Earth’s crust is being pulled underneath another, such as The Philippines or the west coast of South America. This is where a subduction zone can be created.
Alternatively, plate boundaries can be conservative, such as at the San Andreas Fault in California. At this type of boundary, plates slide side by side, often moving in the same direction but at different speeds.
Three main things happen at plate boundaries that can be a hazard if people get in the way . . .
- Volcanoes
2. Earthquakes (New Zealand example)
3. Tsunamis
Plate tectonics are also responsible for creating many of the planet’s most distinctive landforms: fold mountains, tors, volcanic islands to name but a few. Iceland is a great example, as are the Hawaiian Islands.
blographyvarndeancollege 