August 24, 2005
Posted by scott at August 24, 2005 12:02 PM
Apparently one of the classics, though I'd never heard of it, the Paleomap Project provides an era-by-era look at how the continents have wandered around the planet.
Something that's always puzzled me is why any continents are left in the first place. Coastal erosion regularly eats restorts and houses on both US coasts, and I'm sure the phenomena has similar effects all over the world. Why haven't they all eroded away completely? I'm sure it's just that my grasp of geologic processes isn't really that good, but I don't know any geologists to ask for an explanation.
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This process is called "sand sharing." Barrier islands constantly lose sand to downdrift islands, but they constantly gain sand from updrift islands. Storms and high tides can come along and take big bites out of barrier islands, dragging sand offshore - usually, though, the sea puts that sand back onto the beach.
Here is something for you to read. Most erosion stems from human actions
There's also plate tectonics to consider in this.
http://www.crystalinks.com/platetectonics.html - this one has a neat diagram and picture of how things work
http://www.extremescience.com/PlateTectonicsmap.htm this has animated diagrams
Basically, it looks like material is pushed down into the magma layer and then pushed up into the continents and islands via volcanoes.