Simple Lithology

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piedra / wacke
definition Clastic sandstone with more than 10 percent matrix of indeterminate detrital or diagenetic nature. Matrix is mud size silicate minerals (clay, feldspar, quartz, rock fragments, and alteration products). more like this
example graywacke more like this
note Distinction from mudstone is based on inference that less that 50 percent of the mud size fraction (matrix) is original mud size detrital particles. May also grade into diamictite or conglomerate based on size distribution of discernible particles. If more than 50 percent of rock is detrital particles of intrabasinal orgin and carbonate composition, categorize as carbonate wackestone. Term is typically applied to diagenetically altered volcanic-lithic clastic rocks in which the definition of the original clasts has been obscured. Suggested boundaries between wacke and arenite range from 5 to 15 percent matrix. See Dickinson (1970) for discussion of interpretation of undiscernible matrix in diagenetically altered lithic clastic rocks. Dickinson, W.R., 1970, Interpreting detrital modes of graywacke and arkose: Journal of Sedimentary Petrology, v. 40, p. 695-707. more like this
source Pettijohn, Potter, Siever, 1972, Sand and Sandstone: New York, Springer Verlag, 681 p. more like this
type
Resource
Concept
broader clastic sandstone
narrower wacke
in scheme simplelithology
unconsolidated material
definition compoundMaterial composed of an aggregation of particles that do not adhere to each other strongly enough that the aggregate can be considered a solid in its own right. more like this
narrower anthropogenic unconsolidated material
broader unconsolidated material
natural unconsolidated material
broader unconsolidated material
narrower tephra
source This vocabulary more like this
type
Resource
Concept
broader compound material
narrower unconsolidated material
in scheme simplelithology
ultramafic igneous rock
definition Igneous rock that consists of greater than 90 percent mafic minerals. more like this
example alkremite more like this
narrower hornblendite
broader ultramafic igneous rock
komatiitic rock
broader ultramafic igneous rock
peridotite
broader ultramafic igneous rock
pyroxenite
broader ultramafic igneous rock
source LeMaitre et al. 2002; Gillespie and Styles 1999 more like this
type
Resource
Concept
broader igneous rock
narrower
ultrabasic igneous rock
ultramafic igneous rock
in scheme simplelithology
ultrabasic igneous rock
definition Igneous rock with less than 45 percent SiO2. more like this
source after LeMaitre et al. 2002 more like this
type
Resource
Concept
broader igneous rock
in scheme simplelithology
tuffit / tuffite
definition 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). more like this
example volcaniclastic sedimentary rock more like this
note 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. more like this
source LeMaitre et al. 2002; Murawski and Meyer 1998 more like this
type
Resource
Concept
broader rock
narrower tuffite
in scheme simplelithology
tuff breccia agglomerate or pyroclastic breccia
definition Pyroclastic rock in which greater than 25 percent of particles are greater than 64 mm in largest dimension. Includes agglomerate, pyroclastic breccia of Gillespie and Styles (1999) more like this
source Schmid 1981; LeMaitre et al. 2002 more like this
type
Resource
Concept
broader pyroclastic rock
narrower tuff breccia agglomerate or pyroclastic breccia
in scheme simplelithology
travertine
broader chemical sedimentary material
narrower travertine
limestone
narrower travertine
definition Biotically or abiotically precipitated calcium carbonate, from spring-fed, heated, or ambient-temperature water. May be white and spongy, various shades of orange, tan or gray, and ranges to dense, banded or laminated rock. Macrophytes, bryophytes, algae, cyanobacteria and other organisms often colonize the surface of travertine and may be preserved, to produce the porous varieties. more like this
example
calcareous sinter more like this
onyx marble more like this
tufa more like this
source Neuendorf et al. 2005; http://en.wikipedia.org/wiki/Travertine; Chafetz, H.S., and Folk, R.L., 1984, Travertine: Depositional morphology an dthe bacterially constructed constituents: J. Sed. Petrology, v. 126, p.57-74. more like this
type
Resource
Concept
in scheme simplelithology
trachytoid
definition Fine grained igneous rock than contains less than 90 percent mafic minerals, less than 10 percent feldspathoid mineral and less than 20 percent quartz in the QAPF fraction and has a plagioclase to total feldspar ratio less than 0.65. Mafic minerals typically include amphibole or mica; typically porphyritic. Includes rocks defined modally in QAPF fields 6, 7 and 8 (with subdivisions) or chemically in TAS Field T as trachyte or latite. more like this
example
basaltic-trachyandesite more like this
benmoreite more like this
hawaiite more like this
mugearite more like this
potassic-trachybasalt more like this
shoshonite more like this
trachyandesite more like this
trachybasalt more like this
trachydacite more like this
trachyte(TAS) more like this
narrower alkali feldspar trachytic rock
broader trachytoid
latitic rock
broader trachytoid
trachytic rock
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader fine grained igneous rock
narrower
tephritoid
trachytoid
in scheme simplelithology
trachytic rock
definition Trachytoid that has a plagioclase to total feldspar ratio between 0.1 and 0.35. QAPF fields 7, 7', and 7*. more like this
narrower foid bearing trachyte
broader trachytic rock
quartz trachyte
broader trachytic rock
trachyte
note LeMaitre et al. (2002) used 'trachyte' to refer to QAPF fields 7, 7', and 7* in the text (p. 30) as well as to the more restrictive category (QAPF field 7 only). The term Trachytic rock is introduced here to label this more general category of trachyte. more like this
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader trachytoid
in scheme simplelithology
trachyte
definition Trachytoid that has a plagioclase to total feldspar ratio between 0.1 and 0.35, between 0 and 5 percent quartz in the QAPF fraction, and no feldspathoid minerals. QAPF field 7. more like this
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader trachytic rock
in scheme simplelithology
tonalite
definition Granitoid consisting of quartz and intermediate plagioclase, usually with biotite and amphibole. Includes rocks defined modally in QAPF field 5; ratio of plagioclase to total feldspar is greater than 0.9. more like this
example
plagiogranite more like this
trondhjemite more like this
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader granitoid
narrower tonalite
in scheme simplelithology
tholeiitic basalt
definition Tholeiitic basalt is defined here to contain 2 pyroxene phases and interstitial quartz or tridymite or cristobalite in the groundmass. Pyroxene (augite and orthopyroxene or pigeonite) and calcium-rich plagioclase are common phenocryst minerals. Olivine may also be a phenocryst, and when present, may have rims of pigeonite. Only in tholeiitic basalt is olivine in reaction relationship with melt. Interstitial siliceous residue may be present, and is often glassy. Tholeiitic basalt is relatively poor in sodium. This category includes most basalts of the ocean floor, most large oceanic islands, and continental flood basalts such as the Columbia River Plateau. more like this
note Definition of tholeiite and alkali basalt here are more proscriptive 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. more like this
source 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. more like this
type
Resource
Concept
broader basalt
narrower tholeiitic basalt
in scheme simplelithology
tephritoid
alt label
tephritic rock more like this
definition Fine grained igneous rock than contains less than 90 percent mafic minerals, between 10 and 60 percent feldspathoid mineral in the QAPF fraction and has a plagioclase to total feldspar ratio greater than 0.5. Includes rocks classified in QAPF field 13 and 14 or chemically in TAS field U1 as basanite or tephrite. more like this
narrower basanite
broader tephritoid
phonolitic basanite
broader tephritoid
phonolitic tephrite
broader tephritoid
tephrite
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader fine grained igneous rock
in scheme simplelithology
tephritic phonolite
definition Phonolitoid that has a plagioclase to total feldspar ratio between 0.1 and 0.5. Broadly corresponds to TAS tephriphonolite of TAS field U3. more like this
example tephriphonolite more like this
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader phonolitoid
narrower tephritic phonolite
in scheme simplelithology
tephritic foidite
definition 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 less than 10 percent normative olivine more like this
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader foiditoid
narrower tephritic foidite
in scheme simplelithology
tephrite
definition Tephritoid that has a plagioclase to total feldspar ratio greater than 0.9, and contains less than 10 percent normative (CIPW) olivine. more like this
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader tephritoid
in scheme simplelithology
tephra
broader natural unconsolidated material
pyroclastic material
narrower tephra
definition Unconsolidated pyroclastic material in which greater than 75 percent of the fragments are deposited as a direct result of volcanic processes and the deposit has not been reworked by epiclastic processes. Includes ash, lapilli tephra, bomb tephra, block tephra and unconsolidated agglomerate. more like this
narrower ash and lapilli
broader tephra
ash breccia bomb or block tephra
broader tephra
source Hallsworth and Knox 1999; LeMaitre et al. 2002 more like this
type
Resource
Concept
in scheme simplelithology
syenogranite
definition Granite that has a plagiolcase to total feldspar ratio between 0.10 and 0.35. QAPF field 3a. more like this
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader granite
narrower syenogranite
in scheme simplelithology
syenitoid
definition Phaneritic crystalline igneous rock with M less than 90, consisting mainly of alkali feldspar and plagioclase; minor quartz or nepheline may be present, along with pyroxene, amphibole or biotite. Ratio of plagioclase to total feldspar is less than 0.65, quartz forms less than 20 percent of QAPF fraction, and feldspathoid minerals form less than 10 percent of QAPF fraction. Includes rocks classified in QAPF fields 6, 7 and 8 and their subdivisions. more like this
narrower alkali feldspar syenitic rock
broader syenitoid
monzonitic rock
broader syenitoid
syenitic rock
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader phaneritic igneous rock
narrower syenitoid
in scheme simplelithology
syenitic rock
definition Syenitoid with a plagioclase to total feldspar ratio between 0.1 and 0.35. Includes rocks in QAPF fields 7, 7*, and 7'. more like this
narrower foid bearing syenite
broader syenitic rock
quartz syenite
broader syenitic rock
syenite
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader syenitoid
in scheme simplelithology
syenite
definition Syenitic rock that contains between 0 and 5 percent quartz and no feldspathoid mineral in the QAPF fraction. Defined modally in QAPF Field 7. more like this
source LeMaitre et al. 2002 more like this
type
Resource
Concept
broader syenitic rock
in scheme simplelithology
spilite
definition Altered basic to intermediate composition fine-grained igneous rock in which the feldspar is partially or completely composed of of albite, typically accompanied by chlorite, calcite, quartz, epidote, prehnite, and low-tempaerature hydrous crystallization products. Preservation of eruptive volcanic features is typical. more like this
example
meta-andesite more like this
metabasalt more like this
source Fettes and Desmon, 2007; Best, M.G., 1982, Igneous and metamorphic petrology: New York, W.H. Freeman and company, p. 398; Neuendorf et al. 2005, p. 619. more like this
type
Resource
Concept
broader metasomatic rock
narrower
skarn
spilite
in scheme simplelithology
slate
definition compact, fine grained rock with an average grain size less than 0.032 millimeter and a well developed schistosity (slaty cleavage), and hence can be split into slabs or thin plates. more like this
source NADM metamorphic rock vocabulary SLTTm1.0; Neuendorf et al. 2005 more like this
type
Resource
Concept
broader foliated metamorphic rock
narrower slate
in scheme simplelithology
skarn
alt label
exoskarn more like this
tactite more like this
definition Metasomatic rock consisting mainly of Ca-, Mg-, Fe-, or Mn-silicate minerals, which are free from or poor in water. Typically formed at the contact between a silicate rock or magma and a carbonate rock. more like this
source Fettes and Desmons, 2007, p195 more like this
type
Resource
Concept
broader metasomatic rock
in scheme simplelithology
siltstone
alt label
Silt bearing mudstone more like this
definition Mudstone that contains detectable silt. (see comments) more like this
example siltstone more like this
note Use of 'dectable silt' in the criteria for this category is based on the observation that in practice, distinction of claystone from 'siltstone' is typically based on a qualitative assessment of 'grittiness' (e.g. rubbing with fingers, or chewing); the property that these tests can determine is the presence or absence of silty particles in the material. Quantitative grain size analysis in the the clay/silt fraction of a lithified sediment is difficult at best, and of questionable significance because diagensis has altered the size and mineralogy of original sedimentary particles. more like this
source This vocabulary more like this
type
Resource
Concept
broader clastic mudstone
narrower siltstone
in scheme simplelithology