About Geologic Maps

---

Geologic maps are an important source of natural resource information. Whether you are a contractor responsible for a major civil engineering project, or a business considering erecting a new facility, or simply a future homeowner intending to dig a foundation or drill a water well, intelligent planning and problem solving begins with a geologic map!

We strongly recommend reading "Reading Maps with a Critical Eye: Becoming an Informed Map Reader" by the Maine Geological Survey, to get the most out of a geologic map. It is an excellent and concise guide to the different kinds of geologic maps and how to use them.

Benefits of Geologic Maps

Along with other types of geospatial data, geologic maps are essential for evaluating and predicting the consequences of natural and human-induced activities. Such information used in the early stages of planning produces long-term benefits and reduces costs associated with unwanted outcomes after project completion.  Indicated below are just a few of the uses where geologic maps and information are indispensable.

Evaluation of geologic hazards Environmental assessments and protection planning Planning transportation and utility routes Development and protection of groundwater Site selection for landfills, treatment facilities, schools, waste disposal sites Exploration, development and management of natural resources such as sand and gravel and aggregate Regulatory decision making Earth science research Land use planning

Without a doubt, for these uses and for many more, intelligent planning and problem solving begins with a geologic map!

Types of Geologic Maps

There are basically two types of maps. Bedrock geologic maps show the type, age and distribution of bedrock near the earth’s surface.  Surficial geologic maps show the type and distribution of deposits on the earth’s surface that lie on top of the bedrock.