Classificació TAS: diferència entre les revisions
Contingut suprimit Contingut afegit
Línia 42:
== Ús de la classificació TAS ==
Abans d'utilitzar TAS o qualsevol altra classificació, però, cal tenir en compte les següents paraules de Johannsen (1937).
Before using the TAS or any other classification, however, the following words of Johannsen (1937) should be kept in mind.
Many and peculiar are the classifications that have been proposed for igneous rocks. Their variability depends in part upon the purpose for which each was intended, and in part upon the difficulties arising from the characters of the rocks themselves. The trouble is not with the classifications but with nature which did not make things right. … Rocks must be classified in order to compare them with others, previously described, of similar composition and appearance. If this cannot be done on a genetic basis, then an artificial system must answer in order to serve as a card index to rock descriptions. Although this may be an evil thing, it is, at least, the least of several evils.
The subtitle of the classification chapter by Johannsen (1937) is "Chacun a son goût" (to each his own taste).
| |||