| | Classification of Igneous Rocks - flow chart (Site not responding. Last check: 2007-11-02) |
 | | One criticism of the IUGS classification of rocks, discussed by Le Bas and Streckeisen (1991), is that it is deficient in a strong genetic component. |
 | | Lamprophyres are mesocratic to melanocratic igneous rocks, usually hypabyssal, with a panidiomorphic texture and abundant mafic phenocrysts of dark mica or amphibole (or both) with or without pyroxene, with or without olivine, set in a matrix of the same minerals, and with feldspar (usually alkali feldspar) restricted to the groundmass. |
 | | Rocks falling in the shaded areas of the triangular diagrams may be further subdivided according to the diagram within the shaded rectangle. |
| www.geol.lsu.edu /henry/Geology3041/lectures/02IgneousClassify/IUGS-IgneousClassFlowChart.htm (10379 words) |