Using Geologic Maps

The distribution of materials at and below the land surface affects everyone who lives on this planet. In Maine, earth materials control everything from searching for ground water to siting a house foundation to protecting the environment to mining for precious gems. To make informed decisions, there needs to be a system which portrays the complicated pattern of rocks and earth materials which form the land surface. Geologic maps fill this need, portraying information such as the distribution of rock types and unconsolidated materials such as clay, sand, and gravel; landslide and erosion hazards; ground water availability; and much more. Browse the following pages to find out how to become a more informed reader of geologic maps.

Reading and Understanding Geologic Maps

Reading Maps with a Critical Eye: Becoming an Informed Map Reader

Use the links in the following table to learn more about the geologic maps produced by the Maine Geological Survey. The columns are as follows:

Description - description of the map series, and links to the map explanation and sidebar.
How to read - tips on how to read the geologic map.

Bedrock Geology
Map series	Description	How to read
Bedrock	Yes	Yes

Coastal Marine Geology
Map series	Description	How to read
Bluffs	Yes	Yes
Marine Geologic Environments	Yes
Coastal Sand Dune Maps	Yes	Yes
Inner Continental Shelf	Yes

Economic Geology
Map series	Description	How to read
Peat Resource Evaluation	Yes

Geologic Hazards
Map series	Description	How to read
Landslide Hazards	Yes	Yes
Landslide Susceptibility	Yes

Surficial Geology
Map series	Description	How to read
Surficial - detailed	Yes	Yes
Surficial - reconnaissance	Yes
Surficial - 1:250,000	Yes
Surficial Materials	Yes	Yes

Water Resources
Map series	Description	How to read
Sand and Gravel Aquifers	Yes	Yes
Bedrock Ground-Water	Yes
National Wetlands Inventory	Yes

Last updated on October 12, 2011

MAINE GEOLOGICAL SURVEY

Using Geologic Maps

Reading and Understanding Geologic Maps