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Visual Glossary

Basalt dikes cut across granite along the Klondike Highway in Klondike Gold Rush National Historical Park
Basalt dikes cut across granite along the Klondike Highway in Klondike Gold Rush National Historical Park.

Dike

spacer image Dikes are sheet-like or tabular igneous intrusions that cut across sedimentary layering, metamorphic foliation, or other texture of a pre-existing rock.
spacer image The dikes shown in the photograph above are made of basalt that was injected while still molten into older granites.
spacer image Click here to see the same photo with labels.
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This page was last updated on 11/19/99