Coal that has vitrinite mean random reflectance greater than 2.0% (determined in conformance
with ISO 7404-5). Less than 12-14 percent volatiles (dry, ash free), greater than
91 percent fixed carbon (dry, ash free basis). The highest rank coal; very hard, glossy,
black, with semimetallic luster, semi conchoidal fracture.
Economic commission for Europe, committee on Sustainable Energy- United Nations (ECE-UN),
1998, International Classification of in-Seam Coals: Energy 19, 41 pp; see also Neuendorf
et al. 2005; http://en.wikipedia.org/wiki/Coal#Types_of_coal; Eberhard Lindner; Chemie
für Ingenieure; Lindner Verlag Karlsruhe, S. 258
A metamorphic rock of roughly basaltic composition, defined by the presence of glaucophane
with lawsonite or epidote. Other minerals that may be present include jadeite, albite,
chlorite, garnet, and muscovite (phengitic white mica). Typically fine-grained, dark
colored. Category for rocks commonly referred to as blueschist.
Fabric is weakly developed in this rock in many cases, so the fabric categories 'foliated
metamorphic rock, 'schist' or 'granofels' may apply.
A consolidated organic sedimentary material having less than 75% moisture. This category
includes low, medium, and high rank coals according to International Classification
of In-Seam Coal (United Nations, 1998), thus including lignite. Sapropelic coal is
not distinguished in this category from humic coals. Formed from the compaction or
induration of variously altered plant remains similar to those of peaty deposits.
Rock consists of more than 50 percent particles of indeterminate pyroclastic or epiclastic
origin and less than 75 percent particles of clearly pyroclastic origin. commonly
the rock is laminated or exhibits size grading. (based on LeMaitre et al. 2002; Murawski
and Meyer 1998).
volcaniclastic sedimentary rock
In practice, it is likely that any rock for which there is suspicion that it may consist
of redeposited pyroclastic material, usually based on sedimentary structures, irrespective
of the presence or percentage of clearly epiclastic particles, would be called a tuffite.
50 percent cutoff with epiclastic rock is in contrast with LeMaitre et al., but is
used for consistentency with other sedimentary rock categories following the pattern
that the rock name reflects the predominant constituent.
Alkali olivine basalt is silica-undersaturated, characterized by the absence of orthopyroxene,
absence of quartz, presence of olivine, and typically contains some feldspathoid mineral,
alkali feldspar or phlogopite in the groundmass. Feldspar phenocrysts typically are
labradorite to andesine in composition. Augite is rich in titanium compared to augite
in tholeiitic basalt. Alkali olivine basalt is relatively rich in sodium.
The definition of tholeiite and alkali basalt here are more prescriptive than those
found in most reference authorities. This is to actually provide some descriptive
criteria to allow assignment of rocks on a hand sample basis to the tholeiite or alkali
basalt categories if detailed petrographic or chemical data are available.
http://en.wikipedia.org/wiki/Basalt; Carmichael, I.S. Turner, F.J., Verhoogen, John,
1974, Igneous petrology: New York, McGraw HIll Book Co., p.42-43.
Metamorphic rock mainly consisting of green, brown or black amphibole and plagioclase
(including albite), which combined form 75 percent or more of the rock, and both of
which are present as major constituents. The amphibole constitutes 50 percent or more
of the total mafic constituents and is present in an amount of 30 percent or more;
other common minerals include quartz, clinopyroxene, garnet, epidote-group minerals,
biotite, titanite and scapolite.
Coutinho et al. 2007, IUGS SCMR chapter 8 (http://www.bgs.ac.uk/SCMR/)
Fine-grained igneous rock with less than 20 percent quartz and less than 10 percent
feldspathoid minerals in the QAPF fraction, in which the ratio of plagioclase to total
feldspar is greater 0.65. Includes rocks defined modally in QAPF fields 9 and 10 or
chemically in TAS field O2 as andesite. Basalt and andesite, which share the same
QAPF fields, are distinguished chemically based on silica content, with basalt defined
to contain less than 52 weight percent silica. If chemical data are not available,
the color index is used to distinguish the categories, with basalt defined to contain
greater than 35 percent mafic minerals by volume or greater than 40 percent mafic
minerals by weight. Typically consists of plagioclase (frequently zoned from labradorite
to oligoclase), pyroxene, hornblende and/or biotite. Fine grained equivalent of dioritic
Note the mela-andesite and leuco-basalt categories are not recommended in this system.
If chemical analytical data are available to constrain the silica content, the basalt
or andesite category should be used.
Leucocratic phaneritic crystalline igneous rock consisting essentially of plagioclase,
often with small amounts of pyroxene. By definition, colour index M is less than 10,
and plagiclase to total feldspar ratio is greater than 0.9. Less than 20 percent quartz
and less than 10 percent feldspathoid in the QAPF fraction. QAPF field 10, 10*, and
Light coloured crystalline rock, characterized by a fine grained allotriomorphic-granular
(aplitic, saccharoidal or xenomorphic) texture; typically granitic composition, consisting
of quartz, alkali feldspar and sodic plagioclase.
Fine-grained or porphyritic igneous rock with less than 20 percent quartz, and less
than 10 percent feldspathoid minerals, in which the ratio of plagioclase to total
feldspar is greater 0.65. Typically composed of calcic plagioclase and clinopyroxene;
phenocrysts typically include one or more of calcic plagioclase, clinopyroxene, orthopyroxene,
and olivine. Includes rocks defined modally in QAPF fields 9 and 10 or chemically
in TAS field B as basalt. Basalt and andesite are distinguished chemically based on
silica content, with basalt defined to contain less than 52 weight percent silica.
If chemical data are not available, the color index is used to distinguish the categories,
with basalt defined to contain greater than 35 percent mafic minerals by volume or
greater than 40 percent mafic minerals by weight.
Foiditoid that contains less than 90 percent feldspathoid minerals in the QAPF fraction,
and has a plagioclase to total feldspar ratio that is greater than 0.5, with greater
than 10 percent normative olivine.
Highly aluminous material containing abundant aluminium hydroxides (gibbsite, less
commonly boehmite, diaspore) and aluminium-substituted iron oxides or hydroxides and
generally minor or negligible kaolin minerals; may contain up to 20 percent quartz.
commonly has a pisolitic or nodular texture, and may be cemented.
Sediment composed of greater than 50 percent material of biogenic origin. Because
the biogenic material may be skeletal remains that are not organic, all biogenic sediment
is not necessarily organic-rich.
Corresponding biogenic sedimentary material and biogenic sedimentary rock categories
are not included based on the interpretation that biogenic sedimentary rock will be
in a different category, e.g. carbonate sedimentary rock or organic rich sedimentary
Sedimentary rock that consists of at least 50 percent silicate mineral material, deposited
directly by biological processes at the depositional surface, or in particles formed
by biological processes within the basin of deposition.
based on NADM SLTT sedimentary; Hallsworth and Knox 1999
Coal that has vitrinite mean random reflectance greater than 0.6% and less than 2.0%
(determined in conformance with ISO 7404-5), or has a gross calorific value greater
than 24 MJ/kg (determined in conformance with ISO 1928). Hard, black, organic rich
sedimentary rock; contains less than 91 percent fixed carbon on a dry, mineral-matter-free
basis, and greater than 13-14 percent volatiles (dry, ash free). Formed from the compaction
or induration of variously altered plant remains similar to those of peaty deposits.
Economic commission for Europe, committee on Sustainable Energy- United Nations (ECE-UN),
1998, International Classification of in-Seam Coals: Energy 19, 41 pp; see also http://en.wikipedia.org/wiki/Coal#Types_of_coal;
Eberhard Lindner; Chemie für Ingenieure; Lindner Verlag Karlsruhe, S. 258
andesitic rock that contains more than 8 percent MgO. Typically consists of phenocrysts
of protoenstatite, orthopyroxene, clinopyroxene, and olivine in a glassy base full
of crystallites, and exhibits textures characterisitc of rapid crystal growth.
Sedimentary carbonate rock with preserved biogenic texture, whose original components
were bound and encrusted together during deposition by the action of plants and animals
during deposition, and remained substantially in the position of growth.
Coarse-grained material composed of angular broken rock fragments; the fragments typically
have sharp edges and unworn corners. The fragments may be held together by a mineral
cement or in a fine-grained matrix, and consolidated or nonconsolidated. Clasts may
be of any composition or origin. In sedimentary environments, breccia is used for
material that consists entirely of angular fragments, mostly derived from a single
source rock body, as in a rock avalanche deposit, and matrix is interpreted to be
the product of comminution of clasts during transport. Diamictite or diamicton is
used when the material reflects mixing of rock from a variety of sources, some sub
angular or subrounded clasts may be present, and matrix is pre-existing fine grained
material that is not a direct product of the brecciation/deposition process.
Fault material with features such as void spaces (filled or unfilled), or unconsolidated
matrix material between fragments, indicating loss of cohesion during deformation.
Includes fault-related breccia and gouge.
Mudstone that consists of greater than 50 percent carbonate minerals of any origin
in the mud size fraction.
Not a subcategory of carbonate sedimentary rock because definition does not specify
'carbonate minerals of intrabasinal origin', but is agnostic on origin of carbonate.
Schnurrenberger et al. 2003 point out that it is very difficult (at least in lacustrine
rocks) to distinguish chemically precipitated or diagenetic carbonate from primary
biogenic carbonate. This distinction between biogenic, detrital, and pedogenic or
authigenic carbonate material is thus not a good one to use in a general purpose classification
system. Schnurrenberger, D., Russell, J. and Kelts, K., 2003, Classification of lacustrine
sediments based on sedimentary components: Journal of Paleolimnology, v.29, p141-154.
Mudstone that contains between 10 and 50 percent carbonate minerals in the mud size
fraction. Carbonate origin is not specified.
Carbonate-rich mudstone' definition limits carbonate to mud-size fraction to avoid
overlap with 'impure carbonate sedimentary rock'. If carbonate minerals are in sand
or gravel size fractions, use 'impure carbonate sedimentary rock'. The operational
test typically used to identify this category is if the rock fizzes when hydrochloric
acid is applied. The '10 percent carbonate' criteria is a fuzzy boundary.
Sediment in which at least 50 percent of the primary and/or recrystallized constituents
are composed of one (or more) of the carbonate minerals calcite, aragonite and dolomite,
in particles of intrabasinal origin.
Sedimentary material in which at least 50 percent of the primary and/or recrystallized
constituents are composed of one (or more) of the carbonate minerals calcite, aragonite
and dolomite, in particles of intrabasinal origin.
Particularly for fine-grained sedimentary rocks, distinction of 'intrabasinal' versus
'clastic' genesis can be very interpretive. In practice the use of clastic mudstone
terminology as opposed to carbonate mudstone terminology may be dermined by a priori
knowledge about the rock being categorized. If it is associated with other clastic
rocks, the clastic categories will be favored, if with cabonate rocks, the carbonate
categories will be favored. Carbonate rock subcatgories are defined on two orthogonal
dimensions--mineralogy (calcitic vs. dolomitic vs non-carbonate impurities), and texture.
The texture categories used here are those of Dunham (1962), and involve grain size
(matrix vs. grains/allochems), fabric (matrix vs. grain supported), and genesis (bound,
frame, or fragmental). The textural approach used for carbonate rocks is conceptually
incompatible with that used for clastic sedimentary rocks, which is solely grain size
or mineralogy based. This leads to problems in the vocabulary for rocks of mixed siliclastic/carbonate
mineralogy (grainstone vs. sandstone, carbonate mudstone vs. carbonate rich mudstone,
how to accomodate marlstone...).