It may come as a surprise to hear that millions of years ago, when all of present-day North Carolina was covered by an ocean, an arc of volcanoes formed and eventually pushed up through the surface of the water to create a few volcanic islands. Even more surprising is that we can still see visible evidence of that volcanic activity – just by taking a hike.
Whether you’re a lover of geology or just like nature in general, a hike along a certain section of the Eno River in North Carolina is bound to be fascinating.
Google Maps/Rajanikanth T
It’s here along the Eno and dotting a landscape that literally rose from the bottom of an ancient ocean, that rapidly cooled volcanic rock hides in plain sight - in North Carolina, one of the last places we’d expect to find volcanoes.
alltrails/Georgia Loft Yet, even after millions and millions of years of erosion, parts of the Eno are laden with ancient volcanic rock.
If you’re not science geek, you can skip this graphic. But here’s how the magic of plate tectonics created the arc of underwater volcanoes that are now evident in and along the banks of the Eno River.
Wikimedia/ “Subduction-en.svg from Wikimedia Commons by K. D. Schroeder, CC-BY-SA 4.0 First, plate tectonics pushed one plate under another (refer to the yellow arrow above). This caused a hot magma pocket underneath present-day North Carolina to erupt in several places, creating some underwater volcanoes. As the eruptions continued, they eventually pushed through the surface of the ocean to create volcano islands — and the arc was formed (see the top right of the graphic).
Eventually, the magma chamber collapsed under the weight of the erupted material, forming what’s known as the Hillsborough Caldera.
Google Maps/Will Butler There’s no caldera or rim visible to the naked eye today, but geologists believe the caldera was pushed back up when the magma chamber filled again and once again began to erupt. This is the point where the visible volcanic rocks in and along part of the Eno River were created.
The newer volcanic eruptions were also underwater and because water makes lava cool much quicker than air, the volcanic rocks left behind in the Eno have a very distinctive look.
Google Local/Ana Rivas
Rocks and boulders found along a few key trails along the river are hardcore evidence of the area’s strong ties to ancient volcano activity.
veou / iStock / Getty Images Plus Collection via Getty Images This close up of a granodiorite stone shows lava and minerals with the appearance of being embedded into the stone. The process happened as the lava cooled underneath the ancient ocean.
Similar volcanic rocks, called diorite, have more of a granite-like appearance, but still have the very granular texture found in the granodiorte.
alltrails/Hongbo Wang This image, taken along the Buckquarter Creek Loop along the Eno likely contains huge diorite boulders seen in the foreground of the photo.
A few trails along the Eno have been noted as being rich in evidence of the ancient volcanic activity in North Carolina.
Google Maps/Rajanikanth T In a very extensive geology report about the volcanic arc and the Eno River written by Phil Bradley of the North Carolina Geological Survey and published by NCGeology.com, Bradley lists three trails where evidence of ancient volcanic activity is easily seen by the naked eye.
They include the Shakori and Ridge Trails, a 3.9-mile loop.
Google Maps/Rajanikanth T Nearby Holden’s Mill Trail (also a loop), and the Buckquarter Creek Trail (2.4 miles long) are specifically listed as traversing right through the area where the Hillsborough Arc and ancient volcanoes sat.
All trails noted were located significantly west of the park known as West Point on the Eno, near Durham.
alltrails/James Abbott
The next time you’re looking for a nature walk and a history lesson rolled into one, take a hike along the Eno River and discover evidence of North Carolina’s volcanoes!
Google Maps/Rishi Rampersad
It’s important to note that removing rocks and ancient artifacts from these trails is not a good idea. Take the ‘leave no trace’ motto one step further and also ‘take no trace’ when you’re chasing volcanoes along the Eno. Also, be sure to refer to the above AllTrails links for each trail before embarking on your volcano adventure, just to make sure the trails are currently open.
Google Maps/Rajanikanth T
alltrails/Georgia Loft
Yet, even after millions and millions of years of erosion, parts of the Eno are laden with ancient volcanic rock.
Wikimedia/ “Subduction-en.svg from Wikimedia Commons by K. D. Schroeder, CC-BY-SA 4.0
First, plate tectonics pushed one plate under another (refer to the yellow arrow above). This caused a hot magma pocket underneath present-day North Carolina to erupt in several places, creating some underwater volcanoes. As the eruptions continued, they eventually pushed through the surface of the ocean to create volcano islands — and the arc was formed (see the top right of the graphic).
Google Maps/Will Butler
There’s no caldera or rim visible to the naked eye today, but geologists believe the caldera was pushed back up when the magma chamber filled again and once again began to erupt. This is the point where the visible volcanic rocks in and along part of the Eno River were created.
Google Local/Ana Rivas
veou / iStock / Getty Images Plus Collection via Getty Images
This close up of a granodiorite stone shows lava and minerals with the appearance of being embedded into the stone. The process happened as the lava cooled underneath the ancient ocean.
alltrails/Hongbo Wang
This image, taken along the Buckquarter Creek Loop along the Eno likely contains huge diorite boulders seen in the foreground of the photo.
In a very extensive geology report about the volcanic arc and the Eno River written by Phil Bradley of the North Carolina Geological Survey and published by NCGeology.com, Bradley lists three trails where evidence of ancient volcanic activity is easily seen by the naked eye.
Nearby Holden’s Mill Trail (also a loop), and the Buckquarter Creek Trail (2.4 miles long) are specifically listed as traversing right through the area where the Hillsborough Arc and ancient volcanoes sat.
alltrails/James Abbott
Google Maps/Rishi Rampersad
For more information about the ancient volcanoes along the Eno River, you can read Phil Bradley’s full geology report here.
Love discovering odd and interesting things about North Carolina? Most people raise an eyebrow upon learning the true geographical center of North Carolina is found on top of a hill called Purgatory Mountain.
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