BLACKSBURG, Va. (CBSDC) – According to a new study, volcanoes in Virginia are linked to islands on the opposite side of the Atlantic Ocean.
Researchers were hoping to explain the origin of the 48-million-year old volcanoes.
“These young volcanoes are in an area where no one would expect to see volcanic activity,” Sarah Mazza, a geologist at Virginia Tech, and the study’s lead author, told Live Science. “These rocks are our only physical window into processes that helped shape Virginia and even the whole southeastern Appalachia as well.
Geologists thought a hotspot explained the origin of the volcanoes, but Mazza said the results of this study do not agree with a hotspot origin.
Mazza and her team analyzed rocks they collected from the volcanic swarm between Virginia and West Virginia.
The two most prominent examples came from Mole Hill and Trimble Knob. “You probably wouldn’t know they were there unless you talked to a local,” Mazza said.
The researchers concluded that the Virginia volcanoes were not sparked by a hotspot.
They gave three main reasons why this is the case. First, the magma temperature is too low. Second, the magma source is too shallow. Third, they dated the eruptions to between 47 and 48 million years ago; which is at least 10 million years after the hotspot passed through. “That difference is significant enough for us to think this hotspot probably wasn’t the case,” Mazza added.
The researchers proposed that magma reached the surface as pieces of the thick crust beneath Virginia peeled away. Then they believed the magma seeped through the newly thinned crust, reaching the surface through pre-existing crack in the overlying rock.
“I hope this project is a good stepping stone for interpreting what is going on in the crust and the mantle,” Mazza said.
The results were published online in the journal Geology.