A geologic map is actually a form of topographic map, but in this case it shows the type of sediment or rock outcrops exposed at the Earth’s surface, along with the contour lines. The information on these maps can range from the rock type and age to the orientation of rock layers and major (and sometimes minor) geologic features.

Who uses these maps? Most geologists involved in almost every phase of field geology use geologic maps. For example, petrologists use these maps to determine the location of possible economic resources, such as metal ores, water, or oil. Ceomor· phologists use such maps to detect potential hazards in various areas, such as areas prone to earthquakes, flooding, or landslides. Occasionally, geologic profiles are also provided on these maps to help scientists understand, for example, the rock underlying an area.