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Article: Igneous rock associations 4. Oceanic island volcanism I mineralogy and petrology.(Series)
- Article from:
- Geoscience Canada
- Article date:
- March 1, 2005
- Author:
CopyrightCOPYRIGHT 2005 Geological Association of Canada. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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SUMMARY
Oceanic islands tend to occur at the young ends of hotspot trails because they record the passage of oceanic plates over rising convection cells (plumes) in the mantle, of the propagation of cracks in the lithosphere. Basaltic volcanism on oceanic islands is generally unexplosive and, although potentially destructive, poses less threat to human life than volcanism in other tectonic environments. However, the possibility of giant tsunamis from the catastrophic gravitational collapse of islands is of real concern for major cities surrounding the ocean basins.
Two series of magmas are recognized in oceanic islands. Tholeiites form at lower ...