An Investigation of Lower Wilcox Group Coals in Portions of Avoyelles, Catahoula, Concordia, Grant, Lasalle, and Rapides Parishes, Louisiana

Significant accumulations of lower Wilcox Group coals have previously been reported throughout regional reconnaissance studies in north-central Louisiana. The present study is part of a series of contiguous sub-regional studies that incorporate much higher well densities, evaluate each well log individually for coal presence, and map the structures and thicknesses of the Reynolds and the Russell coal. The thickest coal accumulations are found in paralic lagoon deposits in the northern portions of the study area within Lasalle and Rapides Parishes just south of the Angelina-Caldwell Flexure and ontop of the LaSalle Arch. No lower Wilcox Group coals were found south of Township 2N (latitude 31.100° N) in this study. Lower Wilcox Group strata south of Township 2N are interpreted as a shoreline with marine conditions to the south, not suitable for coal accumulation.