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► FIGURĘ 11-1 The submcrńble Alvin shcds light on hydrothemul vems at the Galapagos Kift, a branch of the East Pacific Rbc. Seawater seeps down through thc oceanie crust, becomes heated, and then rises and builds ch:mneys composed of anhydritc (CaSO*) and sulfidcs of iron, coppcr, and zinc The plume of "black smokc” is simpiy heated water saiuratcd with di$solved minerals. Cotnmur.ines of organisms, including tubeworms. guni cUnu. crabs, and <evcral types of fish. )ive ncar the ven»

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Seawaloi enters rock

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-eac-nng o* metale

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FIGURĘ 11-2 Cross secnon of che Red Sea. Water sccps down along fracturcs, becomes heatrd, and dissolves metali from rocks of thc oceanie crust. The hot water then nses, but bccausc it is denscr than seawater, it is crapped m thc AtJancis II Deep where mecals atc precipitaced front solution.