How are Geologic Maps Used?
Basically, geologic maps show distributions and arrangements of geological features. You can tell where certain rocks and features are located on a standard map. Although maps are completely covered with color, in reality, on average, only about 1% of the rocks in an area are exposed. The great majority of the bedrock is covered by soil and consequently not observable. Certainly, some areas have much greater exposure but only in certain regions. Some maps have special shading to show the exposures in an area but most don’t. Exposures on most maps are marked by the structural symbols (strike and dip symbols) but only a representative set of these symbols are included on maps. Therefore the amount of rock that is visible in an area may not be determined. The bands of color or pattern on the map represent a certain geologic unit. They are either single rock types or groups of closely related rock types. Contacts between units are marked with lines that are defined by the certainty of the
