Word: lava
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Dates: during 1990-1999
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Caves can be pounded into existence by ocean waves, plowed open by ice or formed by lava. But to speleologists, the most interesting are those that have been etched out of limestone by acidic water flowing underground. For a long time, researchers believed that nature could accomplish this feat in only one way: through the action of carbonic acid, which is produced when water reacts with carbon dioxide. The weak acid slowly dissolves bedrock. An underground stream forms, and an elaborate network of chambers like those found at Mammoth Cave in Kentucky takes shape. The unusual limestone terrains where this...
...lava and "black smokers" heat up the depths of the oceans, a controversy over whose model correctly predicts the shape of the earth's crust and mantle is heating up geologists at Harvard and around the country...
Miller's minimal use of props was also interesting. A silver cross slung around his neck jingled against the high school ring given him by his boyfriend "from Anaheim." He also cradled a piece of solidified lava to his chest as he talked about the "eruption" of AIDS that had buried so many of his friends...
Forced out by a river of fire, a homeowner left behind wine and glasses as an offering to Mount Etna. And the lava flow, which since December had rolled over earthen barriers and destroyed two farmhouses, came to a near halt last week just short of Zafferana Etnea (pop. 7,000). Was it natural processes -- or were the volcano gods pleased by the wine...
...areas that are remarkably free of craters. That would be easy to explain on a planet like Earth, where cratering from meteor strikes is erased by steady erosion. But while there is some evidence of wind erosion on Venus, the best explanation for the lack of cratering is periodic lava flows. Magellan has found direct evidence of such flows, including domelike upwellings and hardened streams of rock trailing down the sides of Venusian peaks. There are also signs of other geologic activity, including dramatic faulting and several distinct episodes of mountain building. But until last week the evidence didn...