Geology of the Headwaters of the Big Sandy River

from “The Virginia Headwaters of the Big Sandy River: A Story of Revitalization

and Nature’s Resilience”

Physiographic Province

• Appalachian Plateau Province or Cumberland Mountain Province

Age and Formation

• Estimated 250 million years old, formed during the Paleozoic era

• “Building” known as the Alleghenian Orogeny

Appalachian Plateau Province

• Relatively flat and historically stable

• Composed primarily of sedimentary layers

• Rugged due to dendritic erosion

Sandstone

• Clastic sedimentary rock• Tough and common• Sands deposited by seas

that once covered the area

• Responsible for many of the ridges in the area since it is hard to weather

Shale

• Clastic sedimentary rock formed from clay and silt deposits

• Fragile• Basis for much of the

bedrock faulting during orogeny

Limestone

• Sedimentary rock formed by shells and calcium carbonate

• Various uses: decrease damage of acid rain and risk of fires in mines

Karst Topography

• Created by groundwater that dissolves and erodes limestone beneath the surface

• Forms sinkholes, springs, caves, and streams that sink underground

Dolomite

• Sedimentary rock much like limestone, just higher in Magnesium

• Magnesium commonly extracted from it

• Used to make cement