NATIONAL-SCALE 3D MAPPING -- WHAT APPROACH MIGHT BE FEASIBLE FOR THE UNITED STATES?

Since the beginnings of geological surveys in the United States in the 1800s, stratigraphic studies and geologic mapping have been conducted and published. The result is a substantial body of readily available knowledge regarding the regional geologic framework; that is, the Nation’s geology in three dimensions. It is widely recognized that national, regional, and local 3D mapping is urgently needed in order to address societal issues, as well as to provide a general understanding and visualization of the upper portion of Earth’s crust.

In order to contribute to improved understanding of the Nation’s geologic framework, the USGS and the Association of American State Geologists (AASG) are mandated by Congress to provide a National Geologic Map Database (NGMDB, http://ngmdb.usgs.gov/) of standardized, spatial geoscience information, for use by the public and by scientists alike. The NGMDB provides access to >21,000 publications containing stratigraphic columns and cross sections, a subset of which could be used as source information to compile a generalized depiction of the Nation’s 3D geology. The challenge is scientific, not technological – for example, which source publications should be used, how many subsurface horizons should be modeled regionally or (if feasible) nationally, and so forth. Discussion of the feasibility of this work has begun; this presentation will focus on various possible approaches to this work at a generalized, national scale.