# name
A chemical approximation to the modal QAPF and normative Q' (F')-ANOR classification of the igneous rocks based on their SiO2-CaO-K2O content

# metadata.dc.description.abstract[].value
Magmas can form plutonic or volcanic rocks of the same chemical composition. The modal composition of the plutonic rocks can be quantiﬁed but in the case of volcanic rocks this is not always possible, because of its aphanitic texture and presence of glass. These characteristics prevent a mineralogical classiﬁcation in equivalent diagrams for both types of rocks. To resolve this problem, the IUGS recommends the use of chemical TAS diagram in cases where obtaining the modal composition is not possible, in an attempt to adjust its nomenclature to that represented in the QAPF modal diagram. A best approximation is obtained with the normative diagram Q'(F')-ANOR in which the anorthite and the orthoclase are used as a discriminating factor. In this work, the chemical SiO2-100·CaO/(CaO+K2O) diagram is presented, which largely reproduces the aforementioned normative classiﬁcation but in a simpliﬁed form since it uses only three discriminating chemical components (SiO2, CaO and K2O). The delimitation and nomenclature of the ﬁelds has been undertaken empirically using as an example the normative diagram and plotting the analyses of typical igneous rocks. The approximate limit of silica saturation has been drawn as a straight line joining the feldspathic compositions, between orthoclase and anorthite

# metadata.dc.source[].value
Articles publicats en revistes (Educació Lingüística, Científica i Matemàtica)

# metadata.dc.title[].value
A chemical approximation to the modal QAPF and normative Q' (F')-ANOR classification of the igneous rocks based on their SiO2-CaO-K2O content