2014 WYOMING STRATIGRAPHIC NOMENCLATURE CHART

In 2014, the Wyoming Geological Association (WGA) published an updated Wyoming Stratigraphic Nomenclature Chart. WGA published its first comprehensive chart for Wyoming in 1969 and used it in its publications through 2010. The working committee began its efforts in 2001 and selected eighteen areas for individual stratigraphic columns – Fish Creek Basin, Absaroka Basin, Big Horn Basin, Northern Powder River Basin West, Northern Powder River Basin East, Southern Powder River Basin, Green River Basin North and West, Wind River Basin, Shirley Basin, Hartville Uplift, Thrust Belt, Green River Basin South, Washakie Basin, Great Divide Basin, Rawlins Uplift, Hanna Basin, Laramie Basin and North Denver Basin. Sixteen authors contributed to the eighteen columns. The columns were constructed to cover from the Holocene into the Precambrian. The chart incorporated the International Commission on Stratigraphy’s Geologic Time Scale 2004 and displayed both global and North American ages. A datasheet was prepared for all units shown on the chart with information on ages, bounding units, lithology, thickness and related unconformities. In addition, fossil, radiometric, economic and other data were included. References were compiled into a summary list and cited on the datasheets. The final chart was published as a 55 by 39 inch, printed color version with an accompanying DVD. The DVD included an interactive chart with index map, linked to the datasheets. Datasheets were presented as pdf and html files and as a database. The chart itself was provided as pdf files and as Adobe Illustrator files. Individual columns were included as separate pdf and Illustrator files. The committee’s intent was to deliver to geologists a useful tool for deciphering Wyoming’s stratigraphic record.