Petrology and geochemistry of the Fire Clay coalbed, Martin County, Inez 7 ½′ quadrangle, Kentucky, USA

The Middle Pennsylvanian Duckmantian-age Fire Clay coal in the vicinity of Inez, Martin County, Kentucky, USA, is about 80-km northeast of the intensely studied Fire Clay coal in central eastern Kentucky. The moderate-ash, high-S, high volatile B bituminous Martin County Fire Clay coal does not have an obvious volcanic ash parting, one of the major contributors to the rare earth element (REE)-rich central eastern Kentucky Fire Clay coal, and is further from the Pine Mountain thrust fault, the primary driver of hydrothermal metamorphism in the region. Terrigenous input and infiltrational mode of REE emplacement and redistribution were likely factors in the development of the REE chemistry of the Martin County coals, but, without the tuffaceous and strong hydrothermal influences, the overall level of the REE concentration is generally below the levels seen in many other central Appalachian coals.