Stratigraphy and petrography of the Wytheville formation in southwest Virginia

The Wytheville Formation, a newly recognized rock-stratigraphic unit between the Shady Dolomite and the Rome formations, is composed of carbonate rocks which range considerable in lithology between well-defined lower and upper limits. In a number of sections south of Wytheville, Wythe County, Virginia, the nature of the lithofacies is fully exemplified.

The Wytheville Formation, is composed mainly of rather fine-grained, very dark-gray dolomite, much of which is characterized by white calcite and dolomite veinlets. Several distinctive types of chert and minor but conspicuous quantities of fluorite also occur in the formation. In thin section at least nine lithologies are discernible, including both equigranular and inequigranular dolomites, calcitic dolomites, magnesian limestones, micrites, pelsparites, siliceous dolomites, and impure beds ranging from silty dolomitic shales to dolomitic siltstones.

Between Huddle in Wythe County and Allisonia in Pulaski County, Virginia, the Wytheville Formation includes a prominent but localized limestone lithofacies composed mainly of dark-gray micrites and light-gray pelsparites.

Recognition of the Wytheville Formation will be of significance in locating bodies of underlying Shady Dolomite which is not uncommonly highly mineralized. The separate mapping of the Wytheville may therefore be of economic value.