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 強(qiáng)調(diào)指出:所采集的樣品必須新鮮(無(wú)蝕變或極弱蝕變) 、非堆晶的巖石;選擇的判別圖解必須與判別的巖石類(lèi)型相一致,即對(duì)花崗巖類(lèi)要用花崗巖的判別圖解,不能用玄武巖的判別圖解;對(duì)特殊類(lèi)型巖石要選擇專(zhuān)門(mén)用于該類(lèi)型巖石的判別圖解,如堿性花崗巖,鉀質(zhì)火成巖;要應(yīng)用多種圖解綜合判斷;不能用單個(gè)樣品,而應(yīng)作多個(gè)樣品分析;要注意所選擇判別圖解的特別說(shuō)明等。