THE U.S. NATIONAL GEOLOGIC MAP DATABASE

When scientific results are communicated to colleagues, decisionmakers, and the public, the information should be organized and presented so it is clearly and readily understood. Communication is greatly facilitated by the use of widely accepted, standard science terminology and methods. When analytical data and field observations are interpreted to produce a geologic map, the geologist needs to rely on established classifications and nomenclature to describe earth materials.

In the United States, the U.S. Geological Survey and the Association of American State Geologists are mandated by law to build the National Geologic Map Database (NGMDB). Recognizing that standardized geoscience information is necessary for building a national-scale database, the law also mandates the NGMDB to develop the necessary technical and scientific standards. The NGMDB provides access to geoscience maps and associated information, including: 1) various Web-accessible databases (e.g., a Map Catalog of bibliographic information about geoscience maps, a Geologic Names Lexicon, a prototype Paleontology database, and a prototype Image Library of geologic maps); 2) a comprehensive standards-development effort (including development of a standard science language for describing the lithology of earth materials); and 3) eventually, an online database of map information in GIS format.

Two aspects of this project may be of particular interest to Quaternary geologists: 1) the development of a standardized lithologic classification that is compatible with concepts and mapping of Quaternary deposits (for example, “till” requires special consideration because it connotes not just a lithology, but also degree of stratification and environment(s) of deposition), and 2) the compilation of Quaternary information in the U.S. Geologic Names Lexicon is less comprehensive than for older units, given the inherent challenges in correlating and classifying Quaternary units. We solicit comments and guidance about these two efforts, and the overall plan for building the NGMDB. Information about the NGMDB is available at http://ncgmp.usgs.gov/ngmdbproject/.