Geology of Lake Pueblo
Lake Pueblo Park has a rich geologic history. The rock layers visible throughout the park reflect a number of interesting geological processes. According to Brad Sageman of Northwestern University three of the most important processes are the following:
Geologists give names to rock layers that can be traced over large areas. The layers visible in Lake Pueblo Park include, in ascending order, the Dakota Sandstone, Graneros Shale, Lincoln Limestone, Hartland Shale, Bridge Creek Limestone, Fairport Chalky Shale, Blue Hill Shale, Codell Sandstone, and Ft. Hayes Limestone. These rock units can be seen along the dam spillway, through Rock Canyon and up into the Liberty Point area on the North side of the dam.
Geologists also define geologic time by designating specific locations that serve as the standards for all other rocks of the same geologic age. Because Lake Pueblo's Rock Canyon area has one of the best exposures, fossil records, and other characteristics it was chosen as a GSSP (Global Boundary Stratotype Section and Point) - an internationally agreed upon stratigraphic section which serves as the reference for a particular boundary on the geologic time scale. Geologists from around the world travel to Lake Pueblo to study this site.
Fossils are quite common on the park, but please remember that collection of rocks or fossils is prohibited.