Igneous Identification Based on Hierarchical Decomposition

It is essential to identify the lithology of igneous rocks in formation evaluation,whereas the igneous rocks include so various categories that it is hard to distinguish each of them at one time.The proposed measures in this paper may provide another effective method to identify lithology in Dixi Area in Jungger Basin.Firstly established is the hierarchy of lithologic identification by the help of cross plot,and then aligned is the sequence of identified rocks,finally recognized are the corresponding igneous rocks in the established sequence.The hierarchy principle is that,the rock lithology with big acid-base difference is firstly identified from others;rocks with the same lithology are not discriminated by the crossplots,thus,being helpful to next fine lithology discrimination.In this discrimination,if a certain kind of rock can be directly identified from other rocks,it is identified directly without using the given sequence or hierarchy.There are 15 kinds of igneous rocks and 2 kinds of sedimentary rocks were identified,and the coincidence rate is 80.15% comparing with the thin section analysis.The volcanic tuff and volcanic breccia are more difficult to recognize and have a higher error rate than the other igneous rocks′.