Tectonic control of ocean island basalt sources on São Miguel, Azores?

Karsten M. Haase*, Christoph Beier

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


The calderas of the two isotopically distinct volcanoes Sete Cidades and Agua de Pau on São Miguel are only 30 km apart. Sete Cidades lavas generally have 87Sr/86Sr < 0.7038 while Agua de Pau lavas have 87Sr/86Sr > 0.7040. Two overlapping rift zones exist between the two volcanoes and the lava compositions show that each rift zone is connected to the neighbouring volcano. Limited mixing between the volcanic systems implies separate ascent paths and magma sources with diameters of ∼20 km. The two volcanic systems follow contrasting directions; the Sete Cidades volcanic rift strikes NW parallel to the extensional Terceira Rift, while the Agua de Pau volcanic rift zone strikes E-W. The covariation of magma sources and lithospheric tectonics may suggest that the tectonic structure of the lithosphere controls the mantle upwelling beneath São Miguel.

Original languageEnglish
Article number10
Pages (from-to)1-4
Number of pages4
JournalGeophysical Research Letters
Issue number16
Publication statusPublished - 15 Aug 2003
Externally publishedYes


  • Igneous petrology
  • Geochemistry: Isotopic composition/chemistry
  • Geochemistry: Composition of the mantle
  • Volcanology
  • Magma migration


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