Resource Dictionary

Contact

The place or surface where two different kinds of rocks meet. For example, the contact between a limestone and a sandstone. Also, between an igneous intrusion and the host rock that surrounds it. Contacts can be important zones for mineralization because metal-bearing fluids often flow along this plane of weakness. Contacts between older basement rocks and overlying sedimentary rocks (also called “unconformities”) host many of the world’s uranium deposits.