Of passing interest:
http://www.msnbc.msn.com/id/45698645/ns/technology_and_science-science/#.Tuz7pNStRjZ
Christmas Island seamounts: Is the mystery finally solved?
"
The evidence they brought back to the lab told an interesting story: The
rocks' geochemical signatures didn't match those from mid-ocean ridges or
hotspot volcanoes. Instead, they matched the signatures of continental
rocks — in particular, rocks from northwestern Australia.
Using this clue and tectonic plate reconstructions, Hoernle's team traced
the rocks back to the ancient supercontinent of Gondwana.
Around 150 million years ago, greater India, Australia and Burma — all once
part of this supercontinent — began to rift away from each other. This
created the spreading center (or mid-ocean ridge) that eventually formed the
Indian Ocean. As this was happening, the bottom part of the continental
crust delaminated, or "peeled off in a sheet," Hoernle said.
"
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