Rhyodacites,andesites, ferro-basalts and ocean tholeiites from the galapagos spreading center |
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| Authors: | Gary R Byerly William G Melson Peter R Vogt |
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| Institution: | Department of Mineral Sciences, Smithsonian Institution, Washington, D.C. ,USA;U.S. Naval Oceanographic Office, Washington, D.C. ,USA |
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| Abstract: | Volcanic rocks, dredged from depths greater than 1000 m on the Galapagos spreading center, show extreme chemical diversity, including rhyodacites, andesite, ferro-basalts, and low-K oceanic tholeiite. All samples have fresh glassy margins. The ferro-basalts contain up to 18.5% total iron as FeO and up to 3.75% TiO2, while the oceanic tholeiites are as low as 0.02% K2O. The ferro-basalts correlate with the previously proposed zone of high magnetic anomaly amplitudes which flank the Galapagos hot spot, and are consistent with a genesis by shallow fractional crystallization. |
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