MESOZOIC IGNEOUS DIKES AT LAKE JORDAN, NC AND THE BREAK-UP OF PANGEA

Detailed mapping of Mesozoic diabase dikes around Lake Jordan, NC reveals three dike trends, NW-SE, N-S, and NE-SW. Cross-cutting relationships at this location and at Falls Lake, NC suggest a relative emplacement age for the dikes; NW trending dikes appear to be the oldest, followed by N-S trending dikes, and finally followed by the NE trending dikes. The multiple, cross-cutting relationships suggest a non-plume source for the Mesozoic dikes in NC. If these dikes are assumed to be the product of extensional stress fields and not a plume, then the evolution of their orientations is indicative of an evolving stress field during the break-up of Pangea.

Also apparent from the map is a correlation between topographic highs or spits in the lake and the dikes. Many of these topographic highs have old bridges or roads built along them.