Missouri Geological Survey

What are Geologic Maps?

Missouri STATEMAP Geologic Mapping Project  |  Missouri Geologic Map Index
Where may I purchase geologic maps?

Geologic Maps are the foundation of America's infrastructure.  Learn more.

Geologic maps show the distribution, composition, age and structure (folds, faults, etc.) of the various solid materials that make up Earth's crust.

The two most common types of geologic maps are bedrock maps and surficial materials maps. Bedrock geologic maps show the distribution (outcrop pattern) of competent rock (bedrock). They reveal what the pattern of bedrock would look like if all non-bedrock materials (soil, sediments, etc.) were stripped away from the surface. Surficial materials geologic maps, on the other hand, show the distribution of the various unconsolidated materials (soils, sediments, etc.) that cover bedrock.

Geologic maps are used for decision making in 1) exploration and development of coal, oil and gas, metallic minerals, industrial minerals and groundwater, 2) environmental applications such as: pollution prevention and site clean-up, 3) hazard prevention and protection in regard to landslides, earthquakes, karst problems and ground subsidence, 4) engineering of building foundations, roads and highways, railroads, pipelines, utilities, dams, dikes and locks, 5) city planning in regard to zoning decisions, landscaping and building codes, 6) regional planning in waste disposal, transportation and industrial permits, and 7) property valuation in regard to property tax assessment and land acquisition. In short, geologic maps promote sound decision-making in a broad spectrum of activities that are directed towards benefiting man and protecting the environment. The information provided by geologic maps facilitates wise management of the land and its resources.

Geologic maps are normally drawn on topographic base maps that show natural features, cultural features and topographic contours. The scales of topographic base maps and thus the geologic maps drawn on them vary from small-scale to large-scale. Small-scale maps depict large areas in a general manner, whereas large-scale maps depict small areas in much greater detail. Map scales of 1:100,000 or less are generally considered small scales. Map scales larger than 1:100,000 are generally considered large scales. Most modern geologic maps are drawn at large scale on 1:24,000-scale 7.5 minute topographic quadrangle base maps.

Studies show that a 1:24,000-scale geologic map is worth approximately 29 times the cost that one would have to spend gathering the field data and compiling it onto a map.

MGS has been creating and archiving geologic maps of Missouri for more than 100 years. The collection presently contains more than 1,200 individual geologic maps that cover most of the state. These maps were produced by a variety of agencies and individuals, including MGS, U.S. Geological Survey, professors, students and consultants. Map scales range from small to large. It is worth noting that during the past one dozen years, MGS staff have produced 82 detailed 1:24,000-scale geologic maps through the STATEMAP component of the National Cooperative Geologic Mapping Program as administered by the USGS.

Using our Web pages you can locate, view and purchase many of the geologic maps that MGS maintains in its archival collection located in Rolla, Missouri. They are available by calling 573-368-2125 or by visiting our Publications Desk or you may order them from our online store. To locate our office, view this online map.


Availability of Maps

Some quadrangles are not yet available online, while others are presently in-work or have yet to be scheduled for completion. To view listings of available quads, see the listing to the right and click on the quad name of interest.

Current Map Indexes

Future Map Indexes