HELL FOR CERTAIN—A CARBONIFEROUS VOLCANIC ASH IN THE EASTERN USA

The Hell For Certain flint clay bed or tonstein is a new name for the flint clay parting of the Fire Clay coal and the coal's lateral equivalents in the central Appalachian basin. The bed has been mapped in Tennessee, Kentucky, Virginia and West Virginia where it was known as "the flint clay parting" or the "jackrock parting" of the coal. The coal name changes from valley-to-valley or county-to-county, but the names are widely recognized to represent the same coal bed and the flint clay, the same flint clay bed. In practice, the bed is a key stratigraphic horizon used in all these states. "Jackrock" is a mining term and refers to the suitability of the hard flint clay as a floor for mining jacks and other roof support systems.

Numerous researchers in the last two decades have reached the consensus that the widespread bed is an altered volcanic ash, most of the ash altering to kaolinite in the mire environment. The suite of included volcanic minerals and the lack of common resistate sedimentary minerals has been used, among other observations, to support a volcanic origin. Sanidine in the tonstein has been dated by several laboratories and all provide an Ar/Ar date of 311-312 ma, the only confirmed radiometric date for Carboniferous strata in the basin.

The Hell For Certain flint clay or tonstein takes its name from Hell For Certain Creek in northern Leslie County, Kentucky. The Fire Clay (Hazard No. 4) coal was extensively mined in this area. The creek is located in the northern part of the Hyden West 7.5-minute Quadrangle. Outcrops have now been overgrown and access is limited, the creek being the only road in many places. A nearby reference section is a roadcut at mile-marker 40 on the Daniel Boone Parkway reported in Cobb et al, 1981. The name Hell For Certain is appropriate because conditions must have been very difficult during the heavy ash fall.