Geology of the Fall Branch, Tennessee area

This investigation seeks to interpret the stratigraphic and structural relationships of a 43 square kilometer (27 square mile) area at Fall Branch, in northeastern Tennessee. Approximately 2362 meters (7750 feet) of sedimentary rocks ranging from Middle Cambrian to Middle Ordovician in age are exposed in the study area.

Exposures of the Nolichucky Formation consist of three distinct members: a lower shale member; a middle intraclastic and oolitic limestone member; and an upper silty shale member. Detailed examination of the middle limestcne member reveals an offshore depositional environment which became progressively more shallow with time.

The study area is roughly bisected by the northeast Southwest trending trace of the Pulaski thrust fault. Post-Pulaski stress has resulted in the bending of the Pulaski glide plane and subsequent exposure of a window of Sevier Shale near Sulphur Springs.

An exposure of overturned Jonesboro Limestone beds in the northeastern portion of the study area, along Mill Creek, is interpreted to be the result of movement along the Mill Creek thrust fault, which developed in a drag fold along the Pulaski fault.

The southeastern half of the study area is characterized by numerous anticlines and synclines. Many of these folds exhibit bent axial planes indicating that more than one episode of compression was involved in the shaping of these folds.