Detail
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Typical Minerals Ca PLAGIOCLASE & PYROXENE about 50/50Amphibole often present Olivine - absent to trace | Description
A mafic igneous rock from the top of Bowen's Reaction Series. In a color/texture classification this is more what we expect a gabbro to look like, dark in color with both dark pyroxene and mostly dark gray calcium plagioclase (although some white plagiolclase is also present).
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Tectonic Association
Gabbro is typically found on continents in dikes, sills, and laccoliths from slow cooling of mafic magma, mostly derived from hot spots. Gabbro is also part of the oceanic lithosphere (ophiolite suite) forming as a thick layer below the top-most pillow lavas across all the oceanic floors.
 Tectonic Cross Section - pdf version
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| Last Update: 9/29/00 | e-mail: (Fichtels@jmu.edu) |