Book Description

The Late Ordovician Ely Springs Dolomite is a widespread, dark gray to black carbonate unit in central-southeastern California, eastern and southern Nevada, and western Utah. It's most closely related lithologic equivalents are the Hanson Creek Dolomite in north-central Nevada and the Fish Haven Dolomite in northwestern Utah and southern Idaho. The Ely Springs Dolomite and its equivalents are miogeosynclinal sediments occurring in the eastern part of the Cordilleran Geosyncline. Although the Ely Springs Dolomite is readily recognizable as a lithologic unit, it has been subdivided on a local basis only and has not been subjected to detailed stratigraphic analysis. It is the purpose of this study to determine whether it might be possible to recognize subdivisions within the Ely Springs Dolomite that would have regional significance for correlation and environmental interpretation. Furthermore, if such subdivisions proved identifiable, it was hoped to develop a more refined explanation for the origin of the Ely Springs Dolomite, determine the environments in which it was deposited, and to accurately place the events leading to its deposition in geologic time. In pursuit of these objectives, thirteen informally defined members have been identified within the Ely Springs Dolomite and their regional extent determined. Ten lithotopes have been recognized and described. Their distribution, within the sequences studied, provides a basis for understanding the paleogeography and succession of environments during deposition of the Ely Springs Dolomite. Conodonts, brachiopods, corals, and algae have been described and provide information concerning correlation and environmental interpretation.