MS-55 Cenozoic Stratigraphy of Colorado

As a successor to previous Colorado stratigraphy charts (MS-53 Colorado Stratigraphic Chart and MS-54 Cretaceous Stratigraphy of Colorado), this publication resulted from a collaboration between the CGS, USGS, and the Denver Museum of Nature and Science (DMNS). The chart was designed to illustrate Cenozoic stratigraphy spanning the state’s many sedimentary basins. It builds upon the work of dozens of colleagues and updates Richard Pearl’s seminal 1974 stratigraphy chart. The chart leverages the community’s stratigraphic work in both the subsurface and outcrop, and depicts new geochronologic constraints for many units. To facilitate comparison of strata to external forcing factors, the chart employs a linear timescale. Each unit’s dominant depositional environment is depicted, as are major mountain building events, erosional events, and regional unconformities. This high-resolution PDF file may easily be printed up to its original size ~45×26-inches. Digital PDF download. MS-55D

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From the chart itself:

Colorado’s stratigraphy is dominated by gaps. The distribution of strata reflects the tectonic and climatic evolution of each of the region’s basin areas. To foster comparison of these patterns, we have organized the stratigraphy using a linear timescale and illustrated where orogenic uplift has led to removal of strata or nondeposition. Some orogenic features are not illustrated on the chart. In the past ~10 Ma, regional uplift has raised Colorado and ensuing erosion has influenced modern landscape formation. The color scheme for stratigraphic units gives a sense of dominant lithologies and depositional environments across basins. Updates to this chart, as well as additional resources, such as stratigraphic and structural cross-sections, can be found at https://coloradostratigraphy.org. To learn more about the unit names on this chart, resources are available at the U.S. Geological Survey’s Geolex site: https://ngmdb.usgs.gov/Geolex. This chart scaffolds on the work of Richard H. Pearl’s 1977 compilation (Rocky Mountain Association of Geologists, Special Publication 2). This data has been recast against the International Commission on Stratigraphy’s chrono-stratigraphic chart v.2015/01, updated at: https://stratigraphy.org.