"Liesegang banded" sandstone in the Mississippian of Ohio, USA.

The Bowerston Shale Company was founded in the fall of 1929 by Samuel D. Milliken. They have brick manufacturing plants in Bowerston, Ohio and Hanover, Ohio.

The Hanover plant makes bricks using rocks derived from two quarries that I know of - the Hanover Pit and the Frazeysburg Pit. I have visited both, with kind permission of the Bowerston company. The Hanover Pit targets shales of the Vinton Member (Logan Formation), a Lower Mississippian mixed siliciclastics unit. The Frazeysburg Pit targets shales of the Pottsville Group, a Pennsylvanian-aged succession of interbedded shales, limestones, sandstones, coals, flint, clay, and minor ironstone. The shales are excavated at both pits and left in piles in the quarries to weather. Limestones, sandstones, and coals are excluded from the shale piles. Shale material is eventually trucked to the Hanover Plant, where it is processed into bricks.

The rock seen here is from the unusable overburden at the Hanover Pit. The yellowish-brown and brown colored, curving lines and crusts in the rock are iron oxide bands. These features are commonly seen in many porous rocks, particularly sandstones and pebbly sandstones. They have been almost universally referred to as “Liesegang banding”, representing precipitation lines of iron-rich minerals (e.g., hematite, limonite, goethite, etc.) at & along groundwater chemical interfaces. But, according to Neil Wells of Kent State University, the original concept of Liesegang banding (Liesegang, 1896) does not match up with what is seen in the rock record (see Wells et al., 2003).

True Liesegang banding refers to parallel bands of precipitate formed by diffusion along a single chemical gradient during one event. What's seen in the rock record often consists of sets of irregularly concentric iron bands, with different sets of bands quite frequently oriented in different directions, and showing cross-cutting and dissolution of older sets. Iron oxide banding in the rock record is clearly the result of numerous precipitation events over long periods of time by moving groundwater (Wells et al., 2003). Iron oxide mineralization along these bands appears to be induced by the presence of either a redox interface (change from reducing to oxidizing conditions in the groundwater) or a pH interface (change in acidity).

Because Neil Wells is the first (apparently) to point out that what geologists have been calling Liesegang banding really isn’t, a renaming seems to be in order. It was jokingly suggested in 2003 that the iron oxide banding discussed above be called “Wells Banding”. I’m all for that.

Stratigraphy: Vinton Member, upper Logan Formation, Osagean Stage, upper Lower Mississippian

Locality: active quarry, Hanover Pit (Bowerston Shale Company), south of Route 16 & Rock Haven Road, southeast of the town of Hanover, far-eastern Licking County, east-central Ohio, USA (40° 04’ 15.43” North latitude, 82° 14' 44.02" West longitude)

References:

Liesegang, R.E. 1896. Ueber einige Eigenschaften von Gal-lerten [On some properties of gelatin]. Naturwissenschaftliche Wochenschrift 11: 353-362. (see also: Liesegang, R.E. 1945. Geologische Bänderungen durch Diffusion und Kapillarität [Geologic banding by diffusion and capillarity]. Chemie der Erde, Zeitschrift der Chemischen, Mineralogie, Petrographie, Geologie und Bodenkunde 15: 420-423.)