National Geographic : 1977 Oct
UNITED STATES Asaltwater plumbing system N THE GALAPAGOS RIFT-a boundary between separating plates of oceanic crust lava erupts, cools, and cracks. Cold seawater penetrates into fractures and, growing hot, drops off some elements while picking up others-man ganese and silicon-from crustal rocks. Rising through fissures, the hot water flows from the seafloor, where the metal oxides precipitate, or separate out. SOUTH AMERICA DANDELION PATCH GARDEN OF EDEN PAINTINGSANDSCALEMODEL(BELOW)BY WILLIAMH. BOND, NATIONALGEOGRAPHICARTDIVISION Fanciful names distinguish five oases, each with its own fauna, found in the Galapagos Rift (right). In a model (below),Alvinexplores Clambake I, a 50-by-90 -yard oasis fed by plumes of warm water. East west cracks rend the floor as the oceanic plates pull apart.