Heavy-mineral suites in unconsolidated Paleocene and younger sands, western Tennessee

Abstract

Heavy-mineral suites from unconsolidated sands of Wilcox and Claiborne age (Eocene) in the subsurface of western Tennessee were tabulated and compared with heavy-mineral suites obtained from outcropping sands known to be of Midway (Paleocene) and Wilcox age and younger. In the subsurface at Memphis, both pink and colorless garnet are relatively abundant in the Claiborne but rare in the Wilcox. Garnet, however, is very rare in both the Claiborne and the Wilcox in the subsurface 35 miles northeast of Memphis. The mineral is very rare also in the terrace sands of western Tennessee and in samples of the Pliocene(?) and Pleistocene deposits of the Tennessee River in eastern and western Tennessee. It is possible, therefore, that the relative abundance of the mineral garnet is related to the quantity of sediment received from differing source areas in Wilcox and Claiborne times, but that, owing to the shifting of the axis of the embayment, no one source area furnished all the sediment for any formation. Heavy-mineral suites from Pliocene(?) and Pleistocene terrace deposits of the Tennessee River in both eastern and western Tennessee, and heavy-mineral suites from Pliocene(?) deposits of the Mississippi River are much alike, and the only isotropic mineral noted in these sediments was a very rare green mineral. Heavy-mineral suites from Recent deposits of the Mississippi River at Memphis and reported heavy-mineral suites from Cambrian sandstones of Wisconsin and Minnesota differ greatly from heavy-mineral suites of Pliocene(?) terrace deposits of the Tennessee and Mississippi Rivers and include much pink and colorless garnet. The possibility, therefore, is suggested that the Pliocene(?) terrace deposits of the Mississippi River in western Tennessee were derived largely from the basin of the Tennessee River.