Best summary of Plate Tectonics. Climate moves plates too.

Science Daily summarizes advances in knowledge of tectonic plate movement. Tidbits:   It's not continental "drift" because the plates are actively pushed by new material welling at the margins.  Climate drives the process too because rain-induced erosion over time changes the mass of mountain ranges and delta areas. The changes of mass as mountains lower and deltas rise speed and slow plate motion.  Rising mountains create rain-shadows which preferentially shift erosion to the upwind side of those ranges.  The Andean chain is only some 45 million years old but the subduction of the adjacent Nazca plate has been going hundreds of millions of years longer. The oldest mid-ocean ridge material has been dated to 200 million years but above-ocean plate material has been found up to four billion years in age.  Interesting! 

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