Sandstone
Sandstone is a sedimentary rock composed mostly of sand-sized grains cemented by clay, silica, carbonate, or iron oxide. In most places, the majority of the constituent grains are quartz. Sandstone often contains other mineral grains such as feldspar or mica, and very small fragments of pre-existing rocks. When cemented by silica, sandstone has great strength, making it suitable for structural uses.
Most of the sandstone quarried in Arkansas is crushed and used for aggregate in concrete and asphalt. Large blocks (riprap) are used for fill and in dike and jetty construction. Rough, weathered sandstone blocks and boulders (fieldstone) have been used for years as facing stone on homes and other buildings, and to build other structures such as fireplaces, walls, and walkways. Much flaggy sandstone has been produced from the Hartshorne Sandstone (Pennsylvanian) near Midway in Logan County. Other counties in west-central Arkansas that occasionally produce this type of material are Logan, Sebastian, and Franklin. A substantial tonnage of thin flagstone and dimension stone has been produced in the state since the early 1950’s. A large quantity of natural or rough fieldstone used for rustic construction is obtained from bouldery talus and alluvial deposits throughout the Interior Highlands of Arkansas.
There are practically unlimited quantities of sandstone in the Paleozoic Highland area of Arkansas. An almost unlimited amount of this resource is present in the Boston Mountains and, to a lesser extent, in the Springfield and Salem Plateaus. The important sandstone units are principally in the lower Atoka Formation, Bloyd Shale, Hale Formation, Batesville Sandstone, St. Peter Sandstone, and Everton Formation. These sandstone-bearing units range in age from Ordovician to Pennsylvanian. The Arkansas Valley contains vast quantities of sandstone in the Savanna Formation, Hartshorne Sandstone, Atoka Formation, and Hale Formation (all Pennsylvanian). In the Ouachita Mountain region, sandstone is abundant in the Atoka Formation, Jackfork Sandstone, Stanley Shale, Blaylock Sandstone, Blakely Sandstone, and Crystal Mountain Sandstone. These formations range in age from Ordovician to Pennsylvanian.
Major aggregate quarries produce sandstone-based products near the larger cities and at other strategic sites in the Paleozoic Highlands of Arkansas.
Several criteria must be met to determine the best locations for prime aggregate, such as quality of available rock, closeness to market, and available transportation facilities (highways, barges, or railroads). Future demands for sandstone aggregate sources should continue to expand, notably near our larger communities, near and along the Arkansas River, and in the southern Ouachita Mountains. The nearby states of Louisiana, Mississippi, and Texas have been areas of major markets for high-quality Arkansas sandstone. Production of sandstone used for aggregate is included in the section on Crushed Stone.
References
Croneis, Carey, 1930, Geology of the Arkansas Paleozoic area with special reference to oil and gas possibilities: Arkansas Geological Survey Bulletin 3, 457 p.
Haley, B. R., Glick. E. E., Caplan, W. M., Holbrook, D. F., and Stone, C. G., 1979, The Mississippian and Pennsylvanian Systems in the United States – Arkansas: U. S. Geological Survey Professional Paper 1110-O, p. 1-14.
Hendricks, T. A., and Parks, Bryan, 1950, Geology of the Fort Smith District, Arkansas: U. S. Geological Survey Professional Paper 221-E, 94 p.
Miser, H. D., 1934, Carboniferous rocks of the Ouachita Mountains: American Association of Petroleum Geologists Bulletin, v. 18, p. 30-43.
Stone, C. G., and McFarland, J. D., III, with the cooperation of B. R. Haley, 1981, Field guide to the Paleozoic rocks of the Ouachita Mountain and Arkansas Valley Provinces, Arkansas: Arkansas Geological Commission Guidebook 81-1, 140 p.