BGS Rock Classification Scheme - Text search results
45 records found. Please click on a code for a "thumbnail" definition.
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| Description | Code |
|---|---|
| Alkali-feldspar-syenite - A type of syenitic-rock. In the Rock Classification Scheme, it is a coarse-grained crystalline igneous rock whose mineral mode plots in field 6 of the quartz - alkali feldspar - plagioclase - feldspathoid (QAPF) diagram. British Geological Survey Research Report RR/99/06, section 5.1 and figs. 9, 11, 12. | AFSY |
| Foid-bearing-alkali-feldspar-syenite - A type of syenitic-rock. In the Rock Classification Scheme, it is a coarse-grained crystalline igneous rock whose mineral mode plots in field 6' of the quartz - alkali feldspar - plagioclase - feldspathoid (QAPF) diagram. British Geological Survey Research Report RR/99/06, section 5.1 and figs. 9, 11, 12. | FBAFSY |
| Foid-bearing-syenite - A type of syenitic-rock. In the Rock Classification Scheme, it is a coarse-grained crystalline igneous rock whose mineral mode plots in field 7' of the quartz - alkali feldspar - plagioclase - feldspathoid (QAPF) diagram. British Geological Survey Research Report RR/99/06, section 5.1 and figs. 9, 11, 12. | FBSY |
| Foid-syenite - A type of foid-syenitic-rock. In the Rock Classification Scheme, it is a coarse-grained crystalline igneous rock whose mineral mode plots in field 11 of the quartz - alkali feldspar - plagioclase - feldspathoid (QAPF) diagram. British Geological Survey Research Report RR/99/06, section 5.1 and figs. 9, 11, 12. | FDSY |
| Foid-syenitic-rock - A type of coarse-grained normal crystalline rock. In the Rock Classification Scheme, this class includes nepheline-syenite, nepheline-monzosyenite and similar rocks. The term may be used as a field classification when an accurate mineral mode from thin section examination is not available. British Geological Survey Research Report RR/99/06, section 5.1 and figs. 9, 10. | FDSYR |
| Foid-monzosyenite - A type of foid-syenitic-rock. In the Rock Classification Scheme, it is a coarse-grained crystalline igneous rock whose mineral mode plots in field 12 of the quartz - alkali feldspar - plagioclase - feldspathoid (QAPF) diagram. British Geological Survey Research Report RR/99/06, section 5.1 and figs. 9, 11, 12. | FMZSY |
| Kalsilitic rock - A type of exotic crystalline igneous rock. In the Rock Classification Scheme, it is defined as a rock that contains more than 10% modal kalsilite. Kalsilite is a very rare mineral, and its presence is sufficiently important to merit defining rocks with notable kalsilite as a separate group. In the present scheme a threshold value of 10% modal kalsilite has been adopted, the same as the threshold for melilitic rock and leucitic rock. Kalsilite behaves metastably and only rarely survives slow cooling, so virtually all rocks containing kalsilite are fine- or very fine-grained lavas. Coarse-grained rocks containing kalsilite (e.g. kalsilite-bearing syenite and kalsilite-bearing-biotite pyroxenite) have been reported from Russia; however they are extremely rare. British Geological Survey Research Report RR/99/06, section 6.3. | KALR |
| Meta-alkali-feldspar-syenite | MAFSY |
| Alkali-feldspar-microsyenite - A type of microsyenitic-rock. In the Rock Classification Scheme, it is the medium-grained equivalent of alkali-feldspar-syenite. British Geological Survey Research Report RR/99/06, section 5.1. | MCAFSY |
| Foid-bearing-alkali-feldspar-microsyenite - A type of microsyenitic-rock. In the Rock Classification Scheme, it is the medium-grained equivalent of foid-bearing-alkali-feldspar-syenite. British Geological Survey Research Report RR/99/06, section 5.1. | MCFASY |
| Foid-bearing-microsyenite - A type of microsyenitic-rock. In the Rock Classification Scheme, it is the medium-grained equivalent of foid-bearing-syenite. British Geological Survey Research Report RR/99/06, section 5.1. | MCFBSY |
| Foid-microsyenite - A type of foid-microsyenitic-rock. In the Rock Classification Scheme, it is the medium-grained equivalent of foid-syenite. British Geological Survey Research Report RR/99/06, section 5.1. | MCFDSY |
| Foid-micromonzosyenite - A type of foid-microsyenitic-rock. In the Rock Classification Scheme, it is the medium-grained equivalent of foid-monzosyenite. British Geological Survey Research Report RR/99/06, section 5.1. | MCFMSY |
| Foid-microsyenitic-rock - A type of medium-grained normal crystalline rock. In the Rock Classification Scheme, it is the medium-grained equivalent of foid-syenitic-rock. The class includes nepheline-microsyenite and similar rocks. The term may be used as a field classification when an accurate mineral mode from thin section examination is not available. British Geological Survey Research Report RR/99/06, section 5.1. | MCFSYR |
| Nepheline-microsyenite - A foid-microsyenite in which the dominant feldspathoid mineral is nepheline. It is the medium-grained equivalent of nepheline-syenite. British Geological Survey Research Report RR/99/06, section 5.1. | MCNSY |
| Quartz-alkali-feldspar-microsyenite - A type of microsyenitic-rock. In the Rock Classification Scheme, it is the medium-grained equivalent of quartz-alkali-feldspar-syenite. British Geological Survey Research Report RR/99/06, section 5.1. | MCQASY |
| Quartz-microsyenite - A type of microsyenitic-rock. In the Rock Classification Scheme, it is the medium-grained equivalent of quartz-syenite. British Geological Survey Research Report RR/99/06, section 5.1. | MCQSY |
| Microsyenite - A type of microsyenitic-rock. In the Rock Classification Scheme, it is the medium-grained equivalent of syenite. British Geological Survey Research Report RR/99/06, section 5.1. | MCSY |
| Leucomicrosyenite | MCSYL |
| Melamicrosyenite | MCSYM |