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Spatial Data Development and Analysis - Geologic Map Databases

Task Objectives

As noted at the 2007 Updated National Mineral Resource Assessment--Planning Phase Project Workshop, geology is the one critical data input required to conduct deposit-model-based mineral resource assessments. Geologic maps are not a single data type, however, but rather a broad thematic class of spatial data. The kind of detailed homogeneous structured data that a national assessment would ideally use does not exist and is not likely to exist within the life of the current national assessment effort (e.g. complete national 100K digital geologic mapping conforming to a standard data model). The Mineral Resources Program did complete compilation of a digital geologic map database for the conterminous U.S. (the State Geologic Map Compilation database - SGMC) and completed a similar compilation for much of Alaska. In addition, to national level geologic spatial data, assessment work will require more detailed regional mapping to assist permissive terrain definition. During the Updated National Mineral Resource Assessment--Planning Phase Project, we will continue to develop and enhance our existing national level data, create derivative products, and respond to specialized requests from the deposit modeling and assessment related Tasks of the project. In particular, given limited staff resources, it is important that this SubTask address, to the greatest possible extent, specific data requirements defined by the assessment related activities of the Updated National Mineral Resource Assessment--Planning Phase Project.

• Continue to develop and maintain the State Geologic Map Composition database.
• Develop an integrated system for utilizing the State Geologic Map Composition database and other geologic spatial data.
• Develop enhanced attribution for the State Geologic Map Composition database (e.g. additional attribution for intrusive rock polygons or polygons containing black shales)
• Cooperate with other Updated National Mineral Resource Assessment--Planning Pase Project Tasks and other Mineral Resources Program-funded Projects to address spatial data requirements and utilization.
• Catalog and acquire other national and regional geologic compilations and datasets needed for the Updated National Mineral Resource Assessment.

Statement of Work

1. State Geologic Map Compilation Database (SGMC).
   This activity continues development and maintenance of the State Geologic Map Compilation database prepared by the National Surveys and Analysis Projects (1997-2007). All of the SGMC data will be delivered through a centralized site available through the Mineral Resources Program spatial data portal (http://mrdata.usgs.gov/).
   
   During 2008 the SubTask will:
   • Convert the existing Arc/Info coverages to Geodatabase format, and begin to operate the database in a more integrated manner.
   • Begin to look at an attribution schema that integrates state level geologic units into a national legend structure, and design a set of ArcMap styles so that multistate blocks of data will display properly.
   • Add the new state geologic map database for Nevada (1:250K).
   • Assess the need to integrate surficial geologic state maps that were not included in the existing SGMC database.
   • Begin to develop specific derivative maps from the database (e.g. a greenschist facies map, map of the Precambrian, carbonate rocks, etc.)
2. Intrusive rock compilation.
   This work would include updating the data model, integrating existing databases, and compiling states for which no data is available. The basic approach is to add attribution, polygon by polygon, for intrusive rocks from the SGMC map database, although some modifications or additions of polygons may be required. Existing intrusive rock databases include those compiled by the National Surveys and Analysis Projects (Utah, Texas, and the Phanerozoic intrusions of Colorado ), the Headwaters Project (western Montana and northern Idaho), and Great Basin Metallogeny Project (northern Nevada); we will need to reattribute these databases to our data model, which may entail significant work.
3. Black Shale pre-compilation
   One of the priorities for evaluating the national endowment of economically and strategically important black shale-hosted resources, as well as determining the environmental characteristics associated with these sedimentary units, is to compile the extant information on black shale-bearing units as a georeferenced database. Developing information concerning the spatial distribution and chemical characteristics of black shale units will be emphasized. First, we will evaluate what data are available and determine the magnitude of the data compilation effort required to prepare derivative products, including regional map compilations and geochemical databases for black shale units. During the first year of this SubTask we will gather data and develop a strategy and plan for how best to accomplish database compilation.
4. National and regional map compilations.
   This activity consists of systematically identifying national and regional geologic maps, map compilations, and geologic databases of potential value to the Updated National Mineral Resource Assessment. Examples might include a regional basement map of the mid-continent, the lithotectonic map of the Appalachian Orogen, igneous rock databases such as NAVDAT (The western North American Volcanic Rock and Intrusive Rock Database), and so on. These map compilations characterize lithostratigraphy, stratigraphic facies, major structures, metamorphic grade, terranes, depth to basement, and so on. In particular, we are interested in maps that might allow geologic characterization of covered terranes. Activities might include cataloging the existence of paper maps of interest, acquiring and warehousing digital maps and databases as appropriate, and possibly digitizing analog maps of significant value.

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