THE HISTORY, EVOLUTION, AND IMPORTANCE OF GEOLOGICAL MAPS

The use of visual materials to communicate and understand geologic concepts is the foundation of the geological sciences. The use of such material extends back to Georgius Agricola's work in the 16th century. In the 17th century, Martin Lister proposed that soil types in Britain could be plotted on a topographic map. In 1717, Luigi Marsili sketched the distribution of gypsum deposits near Bologna in a single shaded area representing connected gypsum beds in folded sedimentary rocks. In 1757, a naval cartographer created a map of Heligoland upon which he extended the boundaries of four distinct rock units to locations offshore, likely creating the first true geological map. Thirty years later, Jean-Etienne Guettard was asked to create the equivalent of a geologic map of France, but abandoned the project after 11 years of work. In 1815, William Smith published his map of the strata of England and Wales, providing a template for future geological maps. Today, the science of geological mapping is a complex field combining modern technologies with traditional field tools. In addition to traditional bedrock maps, geological maps include geomorphic, resource, and groundwater maps, and a host of variations on the theme of understanding and envisioning the three-dimensional Earth in a two-dimensional space. Uses of geological maps are as varied as are the maps themselves. Geological maps are essential in the search for raw materials, energy resources, and fertile land. These maps provide insight into surficial processes, help geologists, planners, and policy makers recognize and assess natural hazards, and provide critical information used to direct planned development. Geological maps give insight into changes in Earth's surface and provide data that is critical to taking a proactive approach with respect to natural and anthropogenic changes. Geological maps are central to our efforts to understand Earth and the processes at work upon and within our planet. The next-generation of geological maps must be flexible enough to provide the foundation for academic and applied study and at the same time be accessible to non-geologists, providing new knowledge to hikers, bikers, rock-hounds, and others. Making these maps accessible to non-geologists will be critical for the future of publicly-funded geological mapping programs.