Mississippian wood-grained chert and its significance in the western interior United States ( Deseret limestone).

Wood-grained chert is nodular chert which has internal light- and dark-colored, concentric, 3-D, compositional banding resembling grain in wood. The light-colored bands are dolomitic and the dark-colored bands are quartzose with carbonaceous matter. It is recognized in the Mississippian Lodgepole, Deseret, and Great Blue Limestones and some correlatives of these formations in Montana, Utah, and Idaho. The Deseret starved basin model provides a paleogeographic framework that restricts the wood-grained cherts in this basin to the foreslope between the oxygenated carbonate platform margin and the anaerobic-dysaerobic deep water basin. Wood-grained chert may mark the approximate position of the lower limit of the pycnocline in the Deseret starved basin.-from Authors