MANAGEMENT OF GEOLOGIC TAXONOMIES IN THE NATIONAL GEOLOGIC MAP DATABASE PROJECT

Traditionally, taxonomies (terminological hierarchies) are used to describe and interpret geological phenomena such as lithology, structural features, geologic age, and geologic origin. Terminology for these properties usually consists of discrete quanta, possibly multiple; as well, terminology for continuous properties such as color, grainsize, hardness, and modal composition may be expressed via named ranges. In most cases, therefore, the descriptive terminology relating to phenomena depicted on a geologic map can be selected from taxonomic lists. The National Geologic Map Database (NGMDB) project—a cooperative endeavor between the U.S. Geological Survey and the Association of American State Geologists—is interacting with the North American Data Model (NADM) technical teams to develop science language for such taxonomic lists. To date, more than 45 taxonomic categories have been defined that are relevant to describing and interpreting igneous, sedimentary, metamorphic, and surficial earth materials as well as geologic structures. Some of these categories are relatively flat, short word-lists; others present terminological taxa having deep, rich structure. To comply with the unique purviews of Federal and State geologic mapping agencies, extensions and/or revisions of the basic terminology almost certainly will be required. Simply managing this welter of science language, in particular making the necessary correlations among old, new, and continuously evolving terms, is a sizable task. A standardized and managed science language is essential, however, to creation of shared geologic map databases, as envisioned by NGMDB and NADM. This poster presents an overview of taxonomy management, conceptually and technically, and demonstrates some of the software tools that have been developed to facilitate use of taxonomies throughout the NGMDB project.