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Dike identification and geology
A tabular or sheet-like body of igneous rock that cuts across is discordant to the bedding or foliation of the surrounding country rock. Dikes form when magma is injected into fractures and solidifies in place. They range in thickness from centimeters to tens of meters and can extend for kilometers. Dike swarms—clusters of parallel or radiating dikes—indicate regional extension or proximity to a magmatic center. Field: petrology. Example: The Mackenzie dike swarm in northern Canada extends over 3,000 km from a focal point near Coppermine and represents one of the largest dike swarms on Earth, emplaced approximately 1.27 billion years ago.. Related terms: Sill, Discordant, Intrusion, Dike swarm.
Sources, scope & corrections
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
- Editorial owner
- GeoMiner
- Last updated
- 2026-03-30T15:19:41.999576+00:00
- Review status
- Published; not independently peer-reviewed
- USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
- Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.
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