Related science-language activities

Science language bibliography

In a precedent-setting effort, in 1999 the British Geological Survey (BGS) issued four reports that presented a rock-classification for earth materials to be used in geologic-map databases. SLTT used these four reports as a starting point for our deliberations. We adopted major elements of the BGS approach, but found that in order to accommodate North American geologic-mapping traditions and approaches we had to develop slightly modified terminology and taxonomic hierarchies.

• BGS science language for igneous materials (Gillespie and Styles, 1999)
• BGS science language for metamorphic materials (Robertson, 1999)
• BGS science language for sedimentary materials (Hallsworth and Knox, 1999)
• BGS science language for surficial and man-made materials (McMillan and Powell, 1999)

SLTT activities benefitted from a series of International Union of Geological Sciences (IUGS) sub-commissions chartered to develop uniform classifications of earth materials:

• Igneous materials: A long-standing IUGS Subcommission on the classification of plutonic and volcanic igneous rocks has led to a widely accepted standard (IUGS, 1973; MacDonald, 1974; Heiken and Wohletz, 1985; Schmid, 1981; Foley and others, 1987; Streckeisen, 1974, 1976, 1978, 1979; Le Bas and others, 1986; Le Maitre and others, 1989; Le Bas and Streckeisen, 1991).
• Metamorphic materials: An IUGS Subcommission on the classification of metamorphic rocks is underway, and is stimulating wide-ranging discussion of terminology for the naming, description, and genesis of metamorphic rocks.
• Sedimentary materials: An IUGS Subcommission on the geology of sedimentary materials is in the initial phases of its activities.

Science language for glacial sedimentary materials

The International Union for Quaternary Research [INQUA] in the 1970’s sponsored a Commission on Genesis and Lithology of Glacial Quaternary Deposits (Commission C-2). The results of Commission C-2 were published in Goldthwait and Matsch (1988; see Commission summaries in Goldthwaite and others, 1988, p. vii-ix, and Dreimanis, 1988, p. 19-25). The SLTT used this document to develop science language for sedimentary materials of glacial origin.

Geological Survey of Canada (GSC) science language

Concurrent with SLTT activities, the Geological Survey of Canada (GSC) is developing science language for use by GSC projects producing digital geologic-map databases. Through a series of projects, GSC has investigated approaches to developing geological map databases, including prototype data models and user interfaces. Bedrock and surficial geological maps have to date been addressed separately. As part of data modeling, based on variants of NADM, several approaches have been tested to enable interoperability among maps that use varied, usually undefined and sometimes inconsistent science language, particularly for the earth-material constituents of map units.

Two main approaches have been tried, both relying on map context and geological experience as guides to the authors’ meaning. For surficial geological maps, the uncontrolled and variable terminology is reinterpreted within a controlled set of defined terms (a translation, in effect). For bedrock maps, earth material names are “reverse-engineered” into the properties (genetic process, composition, texture, etc.) implied by each name (single word or phrase), using sets of keywords for these properties (Davenport and others, 2002). In both approaches, a hierarchical organization of terms is applied wherever possible to allow for categorization at variable levels of precision in accordance with the information available, and to enable efficient querying of the databases.

For bedrock maps, Struik and others (2002) followed a different approach, recognizing that earth material names are multi-dimensional and can be organized in a variety of hierarchies depending on the choice of criteria (genetic process, composition, texture, etc.). The earth material names that Struik and others (2002) considered were uncontrolled terms gleaned from several published geological maps, but were neither exhaustive nor representative of the entire collection of published maps for Canada. This approach has been extended to collect earth material names in a master list as additional maps are brought into the database, and associate controlled keywords for earth material properties to each unique term (single word or phrase) through a data model that supports multiple ontologies (Davenport, in prep.). This enables map units to be searched or grouped by one or several of these keywords. User interfaces have been written to streamline the analysis of map unit descriptions, extraction of earth material types, and the assignment of keywords.

Federal Geographic Data Committee (FGDC) science language

Within the United States, an important science-language activity is occurring under auspices of the Federal Geographic Data Committee (FGDC) Geologic Data Subcommittee. The FGDC has developed a draft cartographic standard for polygon, line, and point symbols that depict geologic features on geologic maps and digital displays. Although primarily concerned with cartographic technical specifications, the FGDC cartographic standard contains science-language concepts that ultimately must be integrated with and enlarged upon by the NADMSC SLTT group.