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Bulletin Volcanologique

, Volume 44, Issue 3, pp 359–375 | Cite as

New K-Ar ages, chemical analyses and magnetic data of rocks from the islands of santa maria (azores), porto santo and madeira (madeira archipelago) and gran canaria (Canary Islands)

  • G. Feraud
  • J. Gastaud
  • H. U. Schmincke
  • G. Pritchard
  • J. Lietz
  • U. Bleil
Article

Abstract

K/Ar-determinations, major and trace element chemical analyses and magnetic data are reported for rocks from Santa Maria (Azores), Madeira and Porto Santo, and Gran Canaria. Based on these data, the age of the basement of Santa Maria is believed to have formed between about 5.2. and 4.6 m.y.; the unconformably overlying pillow complex interbedded with fossiliferous calcarenites about 3.8 to 3.3 m.y. with the capping subaerial basalt being part of the same magmatic phase. The major erosional phase levelling the basement is thus approximately synchronous with the major Pliocene regression (R2) on Gran Canaria (Lietz andSchmincke, 1975), possibly indicating a widespread eustatic event. The upper part of the submarine, partly fossiliferous series of Porto Santo was dated as ca. 12 to 13 m.y., and the Quaternary age for the major basalt formation in Eastern Madeira (Watkins andAbdel Monem, 1971) is confirmed. The ages of several formations on Gran Canaria were slightly revised.

Chemical differences between basement (shield) and later posterosional series on Gran Canaria are re-emphasized by the new data, while such differences are much less pronounced between the basement and younger series on Santa Maria.

Keywords

Lava Flow Canary Island Alkali Basalt Pillow Lava Geomagnetic Polarity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Intern. Association of Volcanology and Chemistry of the Earth’s Interior 1981

Authors and Affiliations

  • G. Feraud
    • 1
  • J. Gastaud
    • 1
  • H. U. Schmincke
    • 2
  • G. Pritchard
    • 2
  • J. Lietz
    • 3
  • U. Bleil
    • 4
  1. 1.Laboratoire de Géologie et Géochimie, ERA CNRS no. 888, Fac. des Sciences de Nice, Parc ValroseNiceFrance
  2. 2.Institut für MineralogieRuhr-Universität BochumBochumW Germany
  3. 3.German Geological Advisory Group with PetrobanglaDacca 2Bangladesh
  4. 4.Institut für GeophysikRuhr-Universität BochumBochumW Germany

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