GeoRef Subject Categories

Subjects Covered

Subcategories

01A-General mineralogy
01B-Mineralogy of silicates
01C-Mineralogy of non-silicates

Includes

physical, optical, and chemical properties of naturally occurring inorganic minerals and related synthetic minerals, mineral crystallography, including crystal structure, determination of lattice parameters and unit cells, the bonding of atoms and molecules, crystal form and symmetry, collecting minerals, as well as non-mineral gems such as amber and jet

Subcategories

02A-General geochemistry
02B-Hydrochemistry
02C-Geochemistry of rocks, soils, and sediments
02D-Isotope geochemistry

Includes

abundance of elements, organic materials, water, trace elements, isotopes, geochemical processes and properties, geochemical cycles, geochemical surveys analytical methods such as chemical, spectroscopic, thermal, and X-ray and electron microscopy instruments used for analysis

Includes

determination by absolute age methods, including radiometric and radiogenic dating; establishing the chronology of events by methods such as lichenometry, racemization, tree rings, hydration of glass, varves, paleomagnetism, tephrochronology, thermoluminescence, radiation damage, fission-track dating and particle-track dating

Includes

of the planets, asteroids, the Moon and moons of other planets, planetary composition, evolution, surface features, structure, motions

Exclusions

astrophysics and extraterrestrial physics

Subcategories

05A-Igneous and metamorphic petrology
05B-Petrology of meteorites and tektites

Includes

igneous rocks, metamorphic rocks, metasomatism metamorphism, phase equilibria, magmas, lava, intrusions, inclusions, ancient volcanology

Subcategories

06A-Sedimentary petrology
06B-Petrology of coal

Includes

sedimentary rocks, sediments, sedimentation, diagenesis, sedimentary structures, genesis of peat, lignite and coal, clay mineralogy, chemical properties of clay minerals

Includes

continental shelf, continental slope, ocean floors, ocean waves (sediment transport), ocean circulation (sediment transport), reefs (modern)

Exclusions

patterns of ocean circulation
marine biology
wave propagation

Includes

Archaea, Bacteria, life origin, paleontological textbooks, paleontological glossaries, fossil collecting, problematic fossils, ichnofossils (if not related to a specific fossil group)

Includes

algae, Angiospermae, Bryophyta, Cyanobacteria, Fungi, Gymnospermae, Hepaticae, lichens, nannofossils, palynomorphs, Plantae, Pteridophyta

Includes

Annelida, Archaeocyatha, Arthropoda, Brachiopoda, Bryozoa, Cnidaria (Coelenterata), ebridians, Echinodermata, Foraminifera, Graptolithina, Hemichordata, Insecta, Mollusca, Ostracoda, Porifera, Radiolaria, scolecodonts, Silicoflagellata, Thecamoeba, Tintinnida, Trilobita

Includes

Acanthodii, Agnatha, Amphibia, Aves, Chondrichthyes, Chordata, Conodonta, fish, fossil man, Heterostraci, Mammalia, Osteichthyes, Osteostraci, Placodermi, Reptilia, Tetrapoda

Includes

lithostratigraphy (age relationships of rock strata), biostratigraphy, evolution of land masses (continental drift), paleomagnetism, paleogeography, biogeography, paleoclimatology

Includes

area studies dealing with several aspects of geology, entries that might be placed in three or more fields, guidebooks, road logs, bibliographies of geology of an area

Includes

separately published geologic maps, geologic maps with explanatory texts, separately published geologic charts, methodology of geologic mapping

Includes

biography (if not related to a specific field), bibliography (if not related to a specific field), popular geology, elementary geology (textbooks), general mathematical principles, annual reports of geologic surveys and associations, historical accounts, education-curricula, enrollments, directories to geology departments, geology as a profession-career opportunities, forensic geology-geology applied to crime solving

Includes

classical tectonics (regional and local structures resulting from solid-rock movements), faults, fractures, folds, orogeny, geosynclines, deformation, structural analysis, epeirogeny, foliation, lineation

Special Note

Before 1975 the following subjects were found in Structural geology; they are now found in other fields:

Field 05-batholiths, dikes, intrusions, stocks and volcanism
Field 06-breccia, sedimentary structures
Field 12-paleogeography, sea-level changes, unconformities
Field 18-crust, diapirs, geodesy, isostasy, Mohorovicic discontinuity
Field 22-nuclear explosions
Field 23-cratering, cryptoexplosion features
Field 24-glaciers

Subcategories

17A-General geophysics
17B-Geophysics of minerals and rocks

Includes

experimental and theoretical studies of physical properties of rocks, transition states of various compounds under elevated temperature and pressure (applied to core and mantle composition), magnetic and electrical properties of minerals and melts that relate to the Earth's magnetic field; history, development and education in geophysics (since 1981 in Field 18), magnetic and gravity fields of the Earth (since 1981 in Field 18)

Exclusions

Meteorology, magnetosphere, astrophysics, aeronomy and solar physics

Includes

worldwide structure of the Earth, plate tectonics, continental drift sea-floor spreading, paleomagnetism, structure of core, crust and mantle, Mohorovicic discontinuity

Special Note

Prior to 1975 the following subjects were found in Solid-Earth Geophysics; they are now found in other fields:

Field 20-Geophysical surveys
Field 19-Seismology

Includes

earthquakes and elastic waves, including seismograms, wave velocity, seismic sources, seismicity, microearthquakes, microseisms, mechanism of tsunamis and volcanic earthquakes

Includes

applied studies not related to a specific subject including: well-logging, remote sensing, magnetotelluric surveys, gravity surveys, electrical surveys, magnetic surveys, seismic surveys, electromagnetic surveys

Includes

ground water-geochemistry, movement, resources, mathematical models, thermal waters, springs, geysers, fumaroles, soil-water regimes, surface water-chemistry, sediment transport, hydrologic cycle (from 1969 to 1974, fewer references to surface water were included)

Exclusions

biology of surface water, hydraulics

Includes

climate change, ecology, geologic hazards-earthquakes, floods, land subsidence, landslides, debris flows, tsunamis, volcanoes, groundwater pollution conservation, land use, pollution of surface water (seldom covered) reclamation

Special Note

With the growth of the environmental sciences, inclusion of environmental topics has increased dramatically in recent years.

Includes

genesis and evolution of features on the Earth's surface-meteor craters, cryptoexplosion features, eolian features, erosion features, fluvial features, frost action, lacustrine features, mass movements, shore features, solution features, and volcanic features

Includes

the last 2.6 million years of Earth's history, including: archaeology, glacial geology, stratigraphy, palynology, modern volcanology, sea-level changes

Includes

soils-genesis, morphology, evolution, chemistry, erosion and classification

Exclusions

agricultural studies

Subcategories

26A-General economic geology--geology of deposits
26B-General economic geology--economics

Includes

commodity studies-more than one type of commodity mining geology

Subcategories

27A-Geology of metal ore deposits
27B-Economics of metal ores

Includes

metal ores-genesis, resources, economics, exploration, production and utilization (includes uranium)

Subcategories

28A-Geology of nonmetal deposits
28B-Economics of nonmetal deposits

Includes

nonmetal deposits-genesis, resources, economics, exploration, production, and utilization

Subcategories

29A-Geology of energy sources
29B-Economics of energy sources

Includes

petroleum, natural gas, coal deposits (economic studies), oil shale geothermal energy, oil sands

Includes

waste disposal, reclamation, structures-dams, foundations, highways, marine installations, nuclear facilities, reservoirs, tunnels, underground installations and waterways when geologic subjects such as rock and soil properties are discussed

List A - GeoRef Categories/Subjects Covered

General notes

These thesaurus lists, lists A-R, are used by GeoRef indexers for selecting index terms and by searchers for additional information not necessarily found in individual term records in the body of the Thesaurus. In most cases, an hierarchical list is given. In some cases, an alphabetical or other list is provided.

The notes under Searching attempt to guide the searcher in the use of the list. Searchers might also read the notes on Indexing for further clues but should be aware that these notes reflect current practice which in some cases differs from past practice. Further notes on specific terms are in the body of the Thesaurus and additional notes on searching are in the GeoRef Thesaurus, 11th edition Introduction section on searching beginning on page x. Information specific to searching and the individual list topics is included, e.g., a section including commodities begins on page xi.

Under Indexing the current indexing practice is given. These notes should be read along with the instructions under the individual terms in the body of the Thesaurus.

Subject categories

All references included in the GeoRef database are assigned one or occasionally several specific categories. The list of Subjects Covered shows the categories, lettered subcategories, and major topics as well as related topics in other fields, exclusions, and notes on changes in scope.

Generally one major code is selected with the intention of targeting the article to a particular audience. Similar topics are sometimes found under different codes, such as reclamation under both environmental geology and engineering geology. The indexer generally chooses one over the other and rarely may choose to include the article under both topics.

Searching

Beginning in 1981, the specific letter-coded categories are used. The categories may be used in searching both as words (phrases) or codes.

Single words from the codes are often included in the default subject search field. Thus a search for earthquake engineering can be accomplished by combining variant forms of “earthquake” which may be found in the Basic Index available on a searching platform, with “engineering” (either searched in the category field or the default subject search field).

Categories may also be used to eliminate unwanted aspects from a search. A search on magmas, for example, could be restricted to Earth-bound processes by using the Boolean Not with “extraterrestrial”. To distinguish papers on commodities, the user may restrict the category to economic geology, e.g. copper AND economic in category. For geochemical papers, one might want to exclude economic in the category.

When searching categories, keep in mind that certain categories are not used with Quaternary geology 24. Therefore if the searcher wants to include those articles, the search could include the topic as an index term with Quaternary geology as the category, or with Quaternary as an index term, e.g.: igneous rocks and 05* in category; OR igneous rocks and Quaternary in category.

For specific field identifiers, see the documentation for the individual retrieval system. For more information regarding the application of each category code, see Subjects Covered above.

Indexing

In some categories, such as Geochemistry 02, Paleontology 08-11, and Economic Geology 26-29, there is a general category which is used for articles on the discipline or technique, or when more than one of the topics are included in the same article, e.g. when both hydrochemistry 02B and soils 02C are included, then 02A would be selected as the geochemistry category.
Seismology applied to hazards engineering is used with Engineering geology 30, otherwise, seismology is usually placed under geologic hazards in Environmental geology 22, or in Geophysics, seismology 19.
Quaternary geology is placed in category 24 rather than petrology (05, 06), paleontology 08-11, stratigraphy 12, structural geology 16, solid-Earth geophysics 18, geomorphology 23, or soils 25.
Extraterrestrial geology 04 is used alone. If an Earth process or meteorites are discussed in the same record, other categories such as 02 Geochemistry may be used as well.
Areal geology 13 is used where the article deals with three or more separate topics and is concerned with an area.
Areal geology, maps and charts 14 is used for discussions of mapping and maps larger than a standard manuscript page.
General geophysics 17B is used where geophysics of rocks and minerals are related to the Earth’s core or mantle.
Geomorphology 23 papers on landforms use many of the common feature names, such as deltas. Other topics are indexed using environment or sedimentation terms.
Economic geology 26-29 papers which focus on economics rather than geology of the commodity are designated with a B code, e.g. 26B-29B. Articles with a commodity economics focus are rarely covered unless they occur with another topic of interest.