ABSTRACT

Grain-size distribution tests, including parameter comparison plots, equations empirically derived by Sahu (1964), log-log plot of the ratios of selected parameters, CM diagram, and log-probability plots, indicate that the Berne Conglomerate Member of the Logan Formation (Mississippian) of central Ohio probably was deposited in a fluvial-deltaic complex.

Stratigraphers have hypothesized that the conglomeratic unit could be the product of beach, bar, or fluvial-deltaic deposition. Distribution of points in parameter comparison plots relative to previously established environmental boundaries, substantial fine fraction, and configuration of log-probability curves argue strongly against a beach genesis, imply that a bar or spit origin was not probable, and support a fluvial-deltaic origin.

Degree of positive correlation among techniques employed is high and results of the analyses are in accord with recent work by other authors who used sedimentary structures, faunal diversity, and stratigraphic relations to infer a modified deltaic genesis for selected coarse clastic units. Such results appear to strengthen the case for grain-size distribution analysis as one means of paleoenvironment reconstruction and to reiterate the value of multiplicity of approach in the geological sciences.