PRELIMINARY SURFICIAL GEOLOGIC MAP OF MIAMI COUNTY, KANSAS

Miami County is located in the Osage Cuestas physiographic region of eastern Kansas. Gently dipping Pennsylvanian cyclothemic limestones and shales underlie the entire county and have been eroded to create a hilly to gently rolling landscape with a number of east-facing limestone-capped escarpments. The outcrop belt in eastern Kansas comprises some of the most complete Pennsylvanian strata in the world and provides the global reference standard for the upper part of the Pennsylvanian Sub-system in North America.

Miami County is part of the Greater Kansas City metropolitan area and was the fourth fastest growing county in Kansas between the 2000 and 2010 census years, with a population increase of 15.6% and a projected increase of 26.2% over the next 30 years. Much of the recent growth is in the form of semi-rural housing developments that require septic systems. The suitability of these systems is highly dependent on the local surficial geology, which can change drastically over short distances in a landscape comprised of thin alternating beds of limestone and shale as well as up to 5 m-thick chert gravel deposits that mantle a large part of the upland surface.

The extensive exposures of Pennsylvanian carbonates in Miami County are becoming increasingly important sources of limestone aggregate as urban sprawl envelops potential quarry sites, thereby eliminating them from future use. Miami County and its extensive limestone aggregate resources will become increasingly important in providing for transportation infrastructure needs in the growing Kansas City metropolitan area.

The culmination of mapping efforts by the Kansas Geological Survey resulted in a preliminary 1:50,000-scale geologic map of the county. Additional work has recently been completed that integrates data from 33 cores (comprising 2,346 linear ft), 36 outcrops, and 165 geophysical well logs. Datasets include lithofacies descriptions, chemostratigraphic profiles, gamma-ray logs, and conodont biostratigraphy that were integrated to facilitate stratigraphic correlations. These data greatly improve our understanding of the geology of Miami County and are currently being incorporated into the final version of the county geologic map.