rock diagram
1.According to the constructive principles of these diagrams, the following aspects must be thought carefully: the rock types to be studied must be the same or nearly the same as those that can be discriminated by the diagram; To avoid mixed or incorrect signals that could be produced, two or more such diagrams shall have to be jointly used; For special rock types, such as A-type granites or potassic igneous rocks, special discriminative diagrams have to be determined and selected respectively; The samples to be studied can not be altered; In general, the diagrams must be used carefully with Archean samples; The petrotectonic assemblage or an expert system are recommended to be used together with the discrimination diagrams.
