Copyright notice

This article is from the Encyclopedia of North Carolina edited by William S. Powell. Copyright © 2006 by the University of North Carolina Press. Used by permission of the publisher. For personal use and not for further distribution. Please submit permission requests for other use directly to the publisher.

Average: 3.9 (14 votes)


by William G. DiNome, 2006Ashe formation. Image courtesy of the McKinney Geology Teaching Museum, Appalachian State University.

The geologic record suggests volcanic activity in what is now North Carolina primarily occurred in two phases of the middle Proterozoic era, between 850 and 500 million years ago, first while the ancient North American and Euro-African plates were moving apart, then while these same plates were colliding. During the first phase, 840 to 800 million years ago, eruptions occurred under the ancient Iapetus Sea and on land. Volcanic ash and lava flows deposited underwater and interbedded with layers of mud and sand are now part of the Ashe Formation stretching from Ashe and Watauga Counties in North Carolina into Franklin County, Va. The first eruptions on land occurred about 820 million years ago on the Piedmont Terrane, along the present North Carolina-Virginia border in the environs of Mount Rogers. These eruptions continued for at least 220 million years and deposited some 3,000 meters of volcanic and sedimentary rock.

The second phase of volcanic activity, beginning around 750 million years ago and lasting more than 300 million years, occurred along an arc of island volcanoes on the Avalon Terrane, a collision zone between the Iapetus Sea and the Theic-Rheic Ocean. Intense folding and metamorphism have destroyed most evidence of these eruptions, but the rocks created are present in the Carolina State Belt stretching southward through the midsection of the state. The eastern boundary of the belt is undetermined as it lies beneath the Coastal Plain, while the western boundary roughly passes near Greensboro, Thomasville, Lexington, Salisbury, Charlotte, and into South Carolina. Remnant volcanic necks and masses of igneous rock are evident in Orange and Chatham Counties, suggesting an early center of volcanic activity near Chapel Hill, dated at around 700 million years old, and near Hillsborough, dated at about 650 million years old.

Volcanic eruptions may have occurred during the middle Eocene epoch, about 47 million years ago, in the northern and western regions of the state, but erosion has removed all cones or other evidence of such activity. Also, volcanic ash deposits (bentonite) in the Castle Hayne Formation in the Coastal Plain are not believed to be native to the region, but possibly deposited by winds from a volcanic center in Virginia or from eruptions forming the island of Bermuda. There are no known active volcanoes in North Carolina today despite some geologic instability on the coast.



Fred Beyer, North Carolina, the Years before Man: A Geologic History (1991).

Mary-Russell Roberson and Kevin G. Stewart, The Geologic Story of the Carolinas: A Field Guide (2006).

Additional Resources:

Geological Society of American, Bulletin of the Geological Society of America, volume 20.

Stewart, Kevin G., and Mary-Russell Roberson. 2007. Exploring the geology of the Carolinas: a field guide to favorite places from Chimney Rock to Charleston. Chapel Hill: University of North Carolina Press.

Image Credit:

Ashe formation. Image courtesy of the McKinney Geology Teaching Museum, Appalachian State University. Available from (accessed July 30, 2012).



Hello, my family and I are vacationing on the outer banks this year and I noticed that is quite a lot of black sand on the surface of the beach and underneath. My mother thought this might be due to underwater volcanic activity. We usually vacation on Oak Island, which is not to far from here and I've never seen black sand there. I'm wondering if you can solve this predicament for me, thank you!


Hi, Bailey.

Thank you for this great question. I learned something new.

UNC Press published a book in 2004 titled How To Read a North Carolina Beach. The black sand in question might be "heavy-mineral sand," which can become concentrated when the lighter quartz sand is blown away by the wind. You can read more here (starting on page 29:

I hope this helps you answer your question.

Mike Millner, NC Government & Heritage Library


What would be the reason why the towns/ city are named Asheville, Ashe County, and Asheboro" (Ashe)" North Carolina define as ashe from ash or ashes are the solid remains. Where the name Ashe comes from Respectfully?


Hi Arthur,

Thanks for visiting NCpedia and sharing this question. That's a great question.

The name Ashe is in reference to Samuel Ashe, governor of North Carolina from 1795 to 1798. Ashe was a lawyer and prominent patriot to the American cause. Here is a link to his bio in NCpedia:

I hope this helps!  Please let us know if you have additional questions.

Kelly Agan, Government & Heritage Library


Is Mt. Jefferson in North Carolina a volcano?


Hi Jeremy,

Thanks for visiting NCpedia and sharing your question. That's a great question because the area does contain volcanic deposits, known as the Ashe Metamorphis Suite, although the mountain is not a volcano.

You may be interested in this additional information:

•    You’ll find more information about the state’s geology in the additional resources included with the article. 

•    NCpedia article on the Mt. Jefferson State Natural Area, with discussion of the area’s ecology:

•    Ashe Metamorphic Suite, at Appalachian State:

•    And here is an article from the American Journal of Science, Vol. 284, April/May, 1984 on the subject as well:

I hope this helps! Please reply if you have additional questions.

Best wishes,

Kelly Agan, NC Government & Heritage Library


I found a very large snowflake obsidian in a creek near the Pisgah Forest fish hatchery in the creek near a small waterfall. Isn't that rock from volcanic activity?


Dear Dot,

Thanks for visiting NCpedia and sharing this question.  Unfortuantely, NCpedia does not have any additional information on obsidian.  You may want to check out the book included in the resources -- 

Stewart, Kevin G., and Mary-Russell Roberson. 2007. Exploring the geology of the Carolinas: a field guide to favorite places from Chimney Rock to Charleston. Chapel Hill: University of North Carolina Press.

And here is a link to the book in WorldCat --  You can see if a library near you has the book.

Here is also an online resource from Oregan State University that talks about the formation of  "snowflake" obsidian --

I hope this helps!

Best wishes,

Kelly Agan, Government & Heritage Library


How can I get more detailed information about volcanic activity in the Chapel Hill area?
I've already seen information about the Eno River Basin activity around Hillsborough, and am looking for information that would relate to the Morgan Creek area.


Hi Susan,

Thanks for visiting this article on NCpedia and taking a minute to ask your question. And that's a really good question!  

There are a number of government resources that you may want to start with for both historic and current volcanic and seismic activity in the U.S.

You may also want to contact our reference staff here at the Government & Heritage Library (or the reference staff at your local public library).  They can help you get started in your research. Here's the link to their contact information on our website

A copy of this email is also being sent to the email address provided with your comment.

Good luck in your research!

Kelly Agan, NCpedia Staff


Add a comment

PLEASE NOTE: NCpedia will not publish personal contact information in comments, questions, or responses. If you would like a reply by email, please note thats some email servers are blocked from accepting messages from outside email servers or domains. These often include student email addresses from public school email accounts. If you prefer not to leave an email address, check back at your NCpedia comment for a reply. Please allow one business day for replies from NCpedia. Complete guidelines are available at