The redox states of basic and silicic magmas: a reflection of their source regions?

  title={The redox states of basic and silicic magmas: a reflection of their source regions?},
  author={Ian Carmichael},
  journal={Contributions to Mineralogy and Petrology},
  • I. Carmichael
  • Published 1991
  • Geology
  • Contributions to Mineralogy and Petrology
At present the best estimates of the oxygen fugacity of spinel-lherzolites that could be the source material of basic magmas is about five log units below the Ni−NiO buffer to one above it. However partially glassy basic lavas, ranging from MORBs to minettes, all with olivine on their liquidus, cover a wider range, and may have oxygen fugacities that extend to four log units above NNO. Surprisingly the range of oxygen fugacities observed in silicic lavas and ashflows with quartz phenocrysts is… 

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