Part Two II › Division I I › Section 214 214

The Earth's Constituent Minerals and Rocks

Subject Outline

AThe mineral constituents of the Earth
- 1The chemical composition, internal structure, and morphology of minerals
- 2The physical properties of minerals: cleavage; hardness; tenacity; specific gravity; magnetic, optical, and radioactive properties
- 3Classification of minerals in terms of crystal structure and chemical composition
  - aThe principal nonsilicate minerals
    - iNative elements
    - iiSulfides and sulfarsenides
    - iiiSulfosalts
    - ivOxides and hydroxides
    - vHalides
    - viCarbonates
    - viiNitrates and iodates
    - viiiBorates
    - ixSulfates
    - xPhosphates, arsenates, and vanadates
    - xiMolybdates, tungstates, and chromates
  - bThe silicate minerals
    - iSilicate structure and composition: the basic structural unit, the silicon-oxygen tetrahedron
    - iiIsolated and double tetrahedral group silicates
    - iiiRing silicates
    - ivChain silicates
    - vSheet silicates
    - viFramework silicates
- 4The occurrence of minerals in nature
  - aThe major rock-forming mineral groups
    - iThe olivines; e.g., forsterite, fayalite
    - iiThe pyroxenes; e.g., augite, jadeite
    - iiiThe amphiboles; e.g., hornblende, actinolite
    - ivThe micas; e.g., muscovite, biotite
    - vThe feldspars; e.g., orthoclase, albite
    - viThe feldspathoids; e.g., nepheline, leucite
    - viiThe silica minerals; e.g., quartz, tridymite
    - viiiThe clay minerals; e.g., kaolinite, illite
    - ixThe carbonates; e.g., calcite, dolomite [see A.3.a.vi., above]
    - xThe garnets; e.g., almandine, pyrope
    - xiOther major rock-forming minerals; e.g., magnetite, pyrite
  - bThe occurrence of mineral associations and phase equilibrium
    - iIn igneous and metamorphic rocks
    - iiIn sedimentary rocks and precipitates
    - iiiIn the Moon, planets, and meteorites [see also 133.C., 133.E.6.]
  - cOre deposits: concentrations of metals and metalliferous minerals [see also 724.C.3.]
  - dMinerals of gem quality
BRocks and other constituents of the Earth's crust
- 1Igneous rocks
  - aProperties of igneous rocks: composition, texture, and structure
  - bClassification of igneous rocks
  - cFormation of igneous rocks: magmas [see also 212.D.4.]
  - dDistribution and abundance of igneous rocks
  - ePrincipal families of igneous rocks
    - iThe intrusive igneous rocks that result when magma cools and solidifies below the surface of the Earth; e.g., granite, gabbro, diorite
    - iiThe extrusive igneous rocks that form from magma that erupts at the surface of the Earth; e.g., basalt, rhyolite, andesite
    - iiiThe pyroclastic igneous rocks that form from deposits of explosive volcanic eruptions; e.g., pumice, tuff, scoria
- 2Sedimentary rocks
  - aProperties of sedimentary rocks: texture and mineralogical and geochemical composition
  - bClassification systems: clastic, nonclastic
  - cSedimentary structures
  - dSedimentary environments: marine, nonmarine
  - ePrincipal types of sedimentary rocks
    - iConglomerates, breccias, and other heterogeneous clastic rocks (e.g., tillites)
    - iiSandstones: arenites and wackes
    - iiiMudrocks, including shales
    - ivLimestones and dolomites
    - vSiliceous rocks
    - viPhosphorites
    - viiEvaporites [see also 724.B.1.b.]
    - viiiIron-rich sedimentary rocks
    - ixOrganic-rich sedimentary rocks [see 5., below]
  - fDistribution of sedimentary rocks through time
- 3Metamorphic rocks
  - aMetamorphic variables: temperature, pressure, and rock composition
  - bTextural and structural features
  - cOrigin of metamorphic rocks
  - dRocks of the principal facies
  - eDistribution of metamorphic rocks
- 4The rock associations formed in different environments of the Earth's crust
  - aIn the oceanic regions: basaltic lavas, reef limestones, abyssal sediments of the deep oceans
  - bIn the stable continental regions: conglomerates, sandstones, evaporites, coal measures
  - cIn the continental borderlands: sandstones, shales, limestones
  - dIn the island arcs: andesite and spilite lavas, ultrabasic intrusive rocks, graywackes, shales
  - eIn the major mountain ranges: regionally metamorphosed rocks, granitic batholiths, early-stage basalts and peridotites, late-stage andesite lavas
  - fIn the piedmont regions that are adjacent to mountain ranges: gabbros, basalts, arkoses
- 5Fossil fuels
  - aCoals [see also 724.B.1.b. and C.2.]
  - bPetroleum [see also 122.G.1.a. and 724.B.2.and C.1.]
  - cTar sands and oil shales [see also 724.B.2.and C.1.]
  - dNatural gas [see also 122.G.1.a. and 724.B.2.]
COccurrence of the elements in the Earth and its envelope [see also 121.D.1.]
- 1Core
- 2Mantle (depleted and undepleted)
- 3Crust: igneous, sedimentary, and metamorphic rocks; soils
- 4Hydrosphere [see 222.B. and C.]
- 5Atmosphere [see 221.A.]
- 6Biosphere: selective concentration of elements by plants and animals