Word: crusts
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...acid rain. Carbon dioxide, injected into the atmosphere by erupting volcanoes, could have trapped solar heat, disrupting climate through global warming. Even the physical force exerted by the rising plume of molten magma could have contributed to the extinction by uplifting a substantial section of the earth's crust. Since temperatures fall with elevation, says Renne, snow and ice would have quickly accumulated, wrecking ecosystems at higher elevations and contributing to the drop in sea level...
...this theory, the surface of the earth is not a single, rocky shell but a series of hard "plates," perhaps 80 km thick and up to thousands of kilometers across, floating on a bed of partly molten rock. The mid-ocean ridges, geologists argued, were likely locations for planetary crust to be created: the new plate material would be pushed upward by forces from below before it settled back down to form the sea floor...
...because they occur at average depths of about 7,300 ft., oceanographers have been able to visit and study a dozen of them. The vents are essentially underwater geysers that work much the same way Yellowstone National Park's Old Faithful does. Seawater percolates down through cracks in the crust, getting progressively hotter. It doesn't boil, despite temperatures reaching up to 400 degrees C, because it is under terrific pressure. Finally, the hot water gushes back up in murky clouds that cool rapidly, dumping dissolved minerals, including zinc, copper, iron, sulfur compounds and silica, onto the ocean floor...
...always been working-class and industrial rather than an upper-crust residential neighborhood," says Erika S. Bruner, assistant director of the commission...
Twenty years ago, that seemed to be changing. Breakthroughs in scientific understanding of plate tectonics--the incessant shifting of continent-size hunks of the earth's crust--spurred hope that major upheavals could be predicted. In Japan polls showed that 50% or more of the public thought they could be. Tokyo even established an Earthquake Assessment Committee of six eminent seismologists to advise the Prime Minister when he ought to issue a public earthquake warning. But in 17 years no such warning has ever been issued, and many experts think the $100 million a year Japan devotes to trying...