ABSTRACT
This chapter provides a basic grounding in the principles of geology and explains how to apply them. Geologic maps provide information about how rocks are distributed and deformed. The rocks are usually shown as various colors superimposed on a topographic map. "Topo maps" show the ground surface by means of contours of equal elevation. Sometimes, geology is posted directly on air photos or satellite imagery instead of topographic maps. There are general geologic maps as well as specialized geologic maps for many purposes. The chapter describes different types of geological maps, which include standard geological maps, geological hazards maps, seismic hazard maps, paleogeographic maps, soil maps, groundwater or potentiometric surface maps, structure contour maps, mineral alteration maps and so on. Geologic maps are published by the US Geological Survey (USGS) and the Bureau of Land Management (BLM), the Geological Survey of Canada, and other geological surveys.
