ARRANGEMENTS FOR SEAMLESS 3D GEOLOGICAL MAPPING

Research, mapping, monitoring, modeling, and management contribute to benefits. Geology is mapped by administrators, geologists, and information professionals. In federal systems, subnational surveys focus on completeness, and the federal role can be research, technology, and mapping needed to ensure consistency. Procedures are mature for static paper-format maps. Concurrently, all information is transitioning to regularly-updated, multi-resolution, machine-readable, seamless, standardized databases. Nations now foresee a national 3D geology and a 4D digital twin that will house observations and inferences, while supporting monitoring and management. Our work thus consists of publications, standards, and seamless databases. Paper maps are the best reference within a map area, as seamless will never capture everything. Standards will ensure interoperability. Jurisdiction-wide seamless geology is a synthesis of published maps, with steps toward harmonization and facilitation of query. Reconciliation of maps may require fieldwork, if the basis of the mapping differed. Seamless does not have authors, it undergoes audits, and contributors receive credit. In 3D, a layer is a 2D map polygon whose thickness can be mapped, which becomes removable by mapping extent, thickness, properties, heterogeneity, and uncertainty. In layers, we map strata, and in basement, we map structures, then discretized properties. Cross-sections are needed to resolve stratigraphic issues. 3D requires a jurisdictional commitment to databases, collections, and geophysical surveys, with emphasis on public-domain drillhole data. Horizontal resolution is about 100 km for global, 10 km for continental, 1 km for national, 100 m for detailed, and 10 m for soil mapping. Soil mapping is used by modelers to infer properties for the 1^st meter. Status mapping based on local judgement will help to clarify goals, to monitor and manage our progress, to stimulate funding, and to cause us all to strive. We are ready to build seamless 3D from mature 2D for continental resolution, after regional experts clarify what will be layers, and what will be basement. We can begin national resolution seamless 3D within a few years, when we have seamless 2D surficial and bedrock. Detailed seamless will now focus on 2D, and seamless 3D may be geostatistical.