Modifications of the "Quantitative System of Classification of Igneous Rocks"

1912 ◽  
Vol 20 (6) ◽  
pp. 550-561 ◽  
Author(s):  
Whitman Cross ◽  
J. P. Iddings ◽  
L. V. Pirsson ◽  
H. S. Washington
Keyword(s):  
Igneous Rocks

Multidimensional classification of magma types for altered igneous rocks and application to their tectonomagmatic discrimination and igneous provenance of siliciclastic sediments

Lithos ◽  
2017 ◽  
Vol 278-281 ◽  
pp. 321-330 ◽  
Author(s):  
Surendra P. Verma ◽  
M. Abdelaly Rivera-Gómez ◽  
Lorena Díaz-González ◽  
Kailasa Pandarinath ◽  
Alejandra Amezcua-Valdez ◽  
...  
Keyword(s):  
Igneous Rocks ◽  
Siliciclastic Sediments

scholarly journals Suggestions regarding the Classification of the Igneous Rocks

1900 ◽  
Vol 8 (1) ◽  
pp. 1-31
Author(s):  
William H. Hobbs
Keyword(s):  
Igneous Rocks

Chlorite crystallinity as an indicator of metamorphic grade of low-temperature meta-igneous rocks: a case study from the Bükk Mountains, Northeast Hungary

Clay Minerals ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 205-222 ◽  
Author(s):  
P. Árkai ◽  
D. Sadek Ghabrial
Keyword(s):  
Low Temperature ◽  
Electron Microprobe ◽  
Metamorphic Grade ◽  
Igneous Rocks ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Facies Classification ◽  
Increasing Temperature ◽  
Relative Differences

AbstractX-ray diffraction chlorite crystallinity (ChC) indices and major element chemical compositions of chlorites and bulk rocks were determined and correlated in meta-igneous rocks from different Mesozoic formations in various tectonic units of the Bükk Mountains, NE Hungary. The rocks, of basic to acidic compositions, range from ocean-floor metamorphic prehnite-pumpellyite facies (diagenetic zone) through regional metamorphic prehnite-pumpellyite facies (anchizone) up to the regional metamorphic pumpellyite-actinolite and greenschist facies (epizone). As in the case of meta-sedimentary rocks, chlorite crystallinity can be applied as an empirical, complementary petrogenetic tool to determine relative differences in grades of low-temperature meta-igneous rocks. Electron microprobe and XRD data show that ChC is controlled mainly by the decreasing amounts of contaminants (mixed-layered components or discrete, intergrown phases of mostly smectitic composition) in chlorite with advancing metamorphic grade, up to the epizone. The apparent increase in calculated Aliv content of chlorite with increasing temperature is related to the decrease of these contaminants, as stated earlier by Jiang et al. (1994). On the basis of the significant correlations found between ChC and temperatures, derived by the chlorite-Aliv geothermometer of Cathelineau (1988), both methods may be used for estimating the approximate temperatures of metamorphism, in spite of the contrasting interpretation of chemical data from chlorites obtained by electron microprobe analyses. After determining the effects of changing bulk chemistry on chlorite composition and ChC, the chlorite crystallinity method may complement the correlation of the illite crystallinity-based zonal classification of meta-sediments and the mineral facies classification of meta-igneous rocks.

A Quantitative Mineralogical Classification of Igneous Rocks: Revised

1920 ◽  
Vol 28 (2) ◽  
pp. 158-177
Author(s):  
Albert Johannsen
Keyword(s):  
Igneous Rocks

A Quantitative Mineralogical Classification of Igneous Rocks: Revised

1920 ◽  
Vol 28 (3) ◽  
pp. 210-232
Author(s):  
Albert Johannsen
Keyword(s):  
Igneous Rocks

Of the American Quantitative Igneous Rock Classification: Part 5

2012 ◽  
Vol 31 (1) ◽  
pp. 1-41 ◽  
Author(s):  
Davis Young
Keyword(s):  
Igneous Rock ◽  
Essential Elements ◽  
Igneous Rocks ◽  
Single Individual ◽  
Chemical Analyses ◽  
Rock Classification ◽  
Natural Classification ◽  
Quantitative Classification ◽  
The Creation

The preference of the authors of the quantitative igneous rock classification for an artificial rather than a natural system, coupled with their invention of a new nomenclature to accompany the classification, indicates that some essential elements of scientific work are not empirically ascertained but are proposed and accepted (or rejected) by the relevant scientific community as a matter of free choice. The use of igneous rocks as exemplars in the education of novice geology students is discussed. It is claimed that the CIPW classification could not have been produced by a single individual geologist. The factors that allowed for the collective success in the creation of the quantitative classification are examined.Upon publication of their monumental quantitative chemico-mineralogical classification (CIPW 1902, 1903), C. W. Cross, J. P. Iddings, L. V. Pirsson, and H. S. Washington immediately received numerous letters of congratulation. Initial published reviews ranged from highly supportive to suspicious. To help buttress their classification, Washington (1903) published a compilation of igneous rock chemical analyses and Iddings (1903) published several diagrams to drive home the point that a natural classification of igneous rocks was not feasible. Led by Washington, Pirsson, and Cross, several geologists began using the CIPW classification in their petrological studies and some contributed new sub-rang names. In the meantime, Iddings worked on the first volume of a projected two-volume work on igneous rocks based on the quantitative CIPW scheme. Unsympathetic to artificial, overly precise classifications, Harker in particular rejected the CIPW system and its norm calculations and European geologists generally were unenthusiastic. Cross (1910b) offered a major rebuttal to the criticisms, particularly those of Harker, in which he challenged the likelihood of producing a valid natural classification of igneous rocks. Iddings (1913) published the second volume on igneous rocks in which he developed an elaborate correlation between the old qualitative system and the new quantitative CIPW scheme. Washington and Pirsson produced many more petrological studies of Mediterranean volcanic rocks, New Hampshire, and Hawaii that incorporated the quantitative system. Washington (1917) produced a vastly expanded compilation of chemical analyses arranged in accord with the CIPW system. Criticisms, however, continued to mount from Fermor, Daly, Shand, and others, while Tyrrell and Johannsen were lukewarm toward the new classification. The criticism that the CIPW system was of little value in fieldwork repeatedly surfaced. Dissatisfaction with the quantitative scheme led to the publication of many new classifications by geologists, such as Hatch, Winchell, Lincoln, Shand, Holmes, Johannsen, and Niggli. With the creation of satisfactory quantitative mineralogical classifications, the increasing ability to determine the proportions of minerals quantitatively, and the death of Iddings and Pirsson, enthusiasm for the CIPW system gradually began to wane. By the 1960s the classification had become a thing of the past. The value of the norm calculation, however, gained recognition and has survived to the present, assisted no doubt by the capability for doing the necessary calculations by computer.

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