Chert

 

The sources provide information on the chert found in Pocahontas County, West Virginia, including its composition, properties, and uses.

Types and Locations of Chert:

• Huntersville Chert This is a yellow, gray to dark, sandy chert that contains a sparse marine fauna of Oriskany age. It lies below the black Marcellus shale and above the massive Ridgeley Sandstone. The Huntersville Chert outcrops on either side of Beaver Lick-Browns-Michael Mountains.
• Black Chert Black chert occurs in the Hillsdale Limestone, Patton Limestone, and Sinks Grove Limestone.
• Other Cherts The New Scotland and Shriver Cherts are also referenced in the sources.

Properties and Composition:

• Huntersville Chert On fresh exposure, this chert is tough and irregularly bedded. It breaks down into angular fragments that range in size from three-fourths to three inches in diameter. It contains a small amount of lime and occasional streaks of blue to green phosphatic sandstone. A chemical analysis of chert gravel from the Howard Barlow Farm in Huntersville shows it to contain silica, iron oxide, alumina, calcium oxide, and magnesium oxide.
• The Sinks Grove Limestone contains nodules of black chert that are very resistant and were prized by Native Americans for making artifacts.
• The Hillsdale Limestone contains numerous nodules of gray to black chert.

Uses of Chert:

• Road Material Weathered chert beds, especially the Huntersville Chert, make an excellent road-surfacing material. The weathered talus from the Huntersville Chert contains sufficient iron, lime, sand, and alumina to bind well and has been used extensively for road building in Pocahontas County. State routes 42 and 43 between Marlinton and Green Bank have utilized this material. The chert fragments are found weathered out in loose deposits along the outcrop of the Huntersville Chert member, so the material can be readily handled by steam shovels.
• Lime Source The Patton and Hillsdale Limestones are not uniform in character and contain objectionable chert, making their use as a source of lime quite uncertain.
• Artifacts The chert from the Sinks Grove Limestone was used by Native Americans to make artifacts.
• Aggregate The Hillsdale Limestone is especially well adapted for concrete aggregate and road material due to the chert it contains.
• Other The Huntersville Chert breaks down readily into large deposits of chert gravel suitable for road surfacing. The chert contains lime, iron, and alumina to cement readily under traffic.

Locations and Samples:

• Huntersville The type locality of the Huntersville Chert is in the vicinity of Huntersville, where it has been quarried for road material.
• Howard Barlow Farm A sample of chert gravel from the Howard Barlow Farm in Huntersville was tested for chemical and mechanical properties.
• Sherman Gibson Farm Huntersville Chert beds (Oriskany) from the Sherman Gibson farm at Frost were used to surface State route 42 between Green Bank and Marlinton.
• Burr Post-Office At a point one-half mile northwest of Burr Post-Office, a local measurement of the Huntersville Chert was made.
• Mill Point The Hillsdale Limestone, which contains silicified fossils in chert, can be found 0.5 miles northeast of Mill Point.
• Knapp Creek Huntersville Chert was sampled at the top of a quarry 1.5 miles southwest of Frost.
• State Route 42 Genesee Shale was sampled on State Route 42, north side of Knapp Creek, at Mill Run, 2.0 miles southwest of Frost.