EDUCATION: Notes From Underground

Science  27 Jun 2003:
Vol. 300, Issue 5628, pp. 2011a
DOI: 10.1126/science.300.5628.2011a

If you've ever wondered how caves form or why different minerals sometimes share the same chemical formula, dig into The Dynamic Earth, the Web version of geology exhibits at the Smithsonian Institution's National Museum of Natural History. Caves open because acidic ground water seeping through limestone gradually hollows out a cavern. The site descends beneath the surface to see how heat and pressure bend, fold, and cook rocks, often transforming their minerals. The recipe for turning basalt into greenstone, for example, requires between 2000 to 4000 atmospheres of pressure and a long bake at 350°C. You can also wander a gallery of rocks and minerals, such as this chunk of apophyllite and prehnite from Virginia. Launched earlier this year, the Web exhibit is evolving, and curators plan to add sections on plate tectonics and volcanoes and on the solar system.

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