The Virtual Rock Kit -

Rock 11: Diabase

Diabase is an intrusive igneous rock that is approximately 200 million years old (Jurassic aged). The diabase intruded into the Triassic aged sediments and adjacent crystalline rocks as dikes and sills. Diabase is composed of minerals that contain abundant calcium, iron and magnesium in comparison to the Triassic sediments.  Because of the abundance of calcium, iron and magnesium, unique plant communities sometime develop on top of areas underlain by diabase. Diabase is more resistant than the surrounding Triassic sandstones and siltstones and often forms resistant ridges in the Triassic basin. 


diabase small sample
Diabase showing fresh surface and brown colored weathering rind diabase large sample

Diabase showing surface with brown colored weathering rind

diabase large sample2

Please remember that rock and mineral collecting is STRICTLY PROHIBITTED on protected land!



Want to learn more about the geology of the Eno River area?

You may be interested in A Geologic Adventure Along the Eno River - A richly illustrated publication from the North Carolina Geological Survey.