The source urea of the upper Jackfork Sandstone of the southern Ouachita Mountains of Arkansas has been located by means of Cathodoluminescence (CL) of quartz in conjunction with standard petrography. Comparison of frequency distributions of quartz CL colors between the Jackfork and approximately coeval sandstones of the Black Warrior basin detected genetically based affinities which were not apparent by inspection of gross petrology.
The upper Jackfork was derived from the same source area as the Parkwood Formation of the Black Warrior basin of Alabama. The Parkwood is known to have come from the south, and so the Jackfork did also. The Jackfork represents a deep-water lithologic equivalent of the deltaic and nearshore marine Parkwood, deposited as turbidites in the deeper water of the Ouachita trough.