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
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 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