Seismogenic folding in the Mississippian formation of Ohio, USA. This is the Borden Formation, a significant unit in the Lower Mississippian of Kentucky, Indiana, and Ohio. It represents an ancient deltaic succession. Prodeltaic, delta front, and delta top deposits are present in the Borden. Named members in eastern Kentucky and southern Ohio include (from bottom to top) the Henley Member (or Henley Bed), Farmers Member, Nancy Member, Cowbell Member, and Nada Member. Seen here is an interval of soft-sediment deformation within the Cowbell Member. The unit's bedding at this outcrop is folded and chaotic. Such horizons have been called "seismites" or "flow rolls". Seismites are intervals of sedimentary rocks that have been disturbed and deformed by ancient seismic events (earthquakes). In this case, sediments were disturbed, probably liquefied, and moved/flowed. Sediment liquefaction often accompanies significant earthquakes in modern times. Stratigraphy: Cowbell Member, upper Borden Formation, Lower Mississippian. Locality: Portsmouth Bypass roadcut, west of Rose Hill &amp; north of Thomas Hollow Road, northern Scioto County, southern Ohio, USA.
James St. John
CC BY 2.0
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