Visual Glossary

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

Dikes

Dikes are sheet-like or tabular igneous intrusions that cut across sedimentary layering, metamorphic foliation, or other texture of a pre-existing rock.

The dikes shown in the photograph above are made of basalt that was injected while still molten into older granites.

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