Contributions to Mineralogy and Petrology

, Volume 79, Issue 1, pp 46–55 | Cite as

Petrology and mineralogy of dredged gabbro from Gettysburg Bank, eastern Atlantic

  • H. M. Prichard
  • J. R. Cann


Gabbros have been dredged from Gettysburg Bank, 110 km west of Portugal on the Azores/Gibraltar fracture zone. Primary minerals in olivine, pyroxene and brown hornblende gabbros are partially replaced by metamorphic minerals. Igneous textures are inhomogeneously overprinted by a granular polyhedral deformation and a cataclastic deformation. Amphiboles show characteristics which indicate a transition from crystallisation in a magma chamber to formation of amphibole in solid gabbro under metasomatic conditions. Of the amphiboles analysed, chlorine was present in the green amphiboles but below 0.05% in the brown suggesting the penetration of sea water after the formation of the brown amphibole but during the formation of the green.


Chlorine Olivine Mineral Resource Fracture Zone Primary Mineral 
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

© Springer-Verlag 1982

Authors and Affiliations

  • H. M. Prichard
    • 1
  • J. R. Cann
    • 2
  1. 1.Department of Earth SciencesThe Open UniversityMilton KeynesEngland
  2. 2.Department of GeologyUniversity of Newcastle-upon-TyneNewcastle-upon-TyneEngland

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