10 Volcanoes in New Jersey?

One of my new hobbies is rock collecting and geology. Rock collecting (or rock observing where collecting is not allowed) is a relatively cheap hobby, and it gets me out of the house which is healthy for the mind and body.

New Jersey is famous for fluorescent minerals, like willemite, found in the Franklin, New Jersey area. I was thrilled to learn that New Jersey has fluorescent minerals outside of the Franklin area, like sodalite in the Beemerville nepheline syenite mass. Around the same time I learned of the sodalite, a family member sent me a link to a story about the New Jersey volcano, Rutan Hill.

I downloaded Google Earth and installed a KMZ file of New Jersey geological data to check out the volcano and the nepheline syenite mass where the sodalite is found.

The pink areas are the nepheline syenite, the red areas are ouachitite breccia, and the “R” is the Rutan Hill volcano. The USGS page about ouachitite breccia says it is found chiefly “in numerous diatremes in the Beemerville area; largest of at Rutan Hill.” Diatremes, “are sometimes known as a maar-diatreme volcano” (quoting Wikipedia). If Rutan Hill is a diatreme volcano, the rest of the red areas below are probably also diatremes. Counting the red areas on the map, there are 10 “volcanos” in New Jersey. Not active volcanos, but old ones nonetheless. Cool. Now I want to buy a house on one of them. Interestingly, Grammarly wants me to change “on” to “in”. I don’t want to live “in” a diatreme, Grammarly.

10 Volcanoes in New Jersey

You can see some of these features in Lidar data as well. This is not the same scale and area as the Google Earth map:

Lidar Hillshade