Volcanoes Are a Notable Part of Virginia History

By Jim Beard

Although there are no active volcanoes in Virginia now, they are an important part of our geologic history. Around the state, geologists have found lava and ash that has erupted from ancient volcanoes.

Some of the oldest lava flows in Virginia are found in the area around Mount Rogers. At Grayson Highlands State Park, visitors can see lava that is more than 700 million years old. This lava was very stiff and sticky. In some places we can see where the sticky lava has picked up rocks and soil as it flowed over them, just like your bubble gum will pick up sand if you drop it on the beach.

At Shenandoah National Park and elsewhere along the Blue Ridge, lava 550 million years old still contains many features seen in modern lava flows, including gas bubbles and “pillows” formed by underwater eruption.

Layers of volcanic ash are found in the sedimentary rocks of Catawba Mountain in Roanoke County. This ash spewed from volcanoes that may have been hundreds of miles away.

The largest volcanic eruptions in Virginia’s history occurred 180 million years ago. These eruptions marked the birth of the modern Atlantic Ocean. Within 1 million years (and possibly less), eruptions covered not only much of Virginia but large areas of North and South America, Europe and Africa. The evidence of this huge outpouring of lava can be seen in many places around the state, including the Haymarket area of Loudoun County and along U.S. 460 near Farmville.

Monterey is home to a hill called Trimble Knob just outside of town. This hill is the eroded throat of one of the youngest volcanoes in eastern North America. This volcano and others nearby in Highland County and Harrisonburg are a mere 47 million years old.

Virginia science Standards of Learning: 4.8; 5.7; ES.8.

On the Web

U.S. Geological Survey: http://pubs.usgs.gov/gip/volcus/ index.html

National Geographic Kids: www.nationalgeographic.com/ngkids/0106/ volcano/volcano_q1.html

Volcanoes Online: http://library.thinkquest.org/17457/ english.html

Jim Beard is curator of geology at the Virginia Museum of Natural History in Martinsville.

MEMO: SCI-KIDS

Originally published by Special Correspondent.

(c) 2007 Richmond Times – Dispatch. Provided by ProQuest Information and Learning. All rights Reserved.