The application of radar chart in geoscience and its significance

The radar chart method is a very common method among all the multi-statistic charts that can project the status of each index to the two-dimensional plane, and it gets its name for its similarity with the images shown on radar navigation screens. Now, although the radar chart method has already been broadly used in evaluating company performance, financial situations, human resources, risk and so on, it is seldom applied in the geosciences, especially petrology, minerology, geochemistry, structural geology, and geophysics. Compared with traditional basalt discrimination diagrams, the radar chart has advantages in comprehensive analyses, for each of its axes can represent not only data information but also geological phenomena and geological background information. Radar charts can combine all kinds of different indicators, which means they share a same thinking mode with the prevalent analytical method called Big Data analytics. Radar charts can represent not only data information but also other scientific factors, such as observations and geological records, which give it more advantages in composite analyses. The scope of the application of radar charts is scalable, meaning they can be used to analyze global statistical information or just evaluate the data of a particular region. The number of factors of every radar chart varies but usually ranges from three to ten or more. The practical uses of radar charts cannot be fully illustrated, thus, only a few geological examples are presented in this paper in an effort to explain their priority in classification. The research shows that radar charts can simplify the usage of different diagrams in the geosciences by considering the most typical indicators of different problems. For example, when discriminating the tectonic settings of the basalts, a five-dimensional radar chart containing the factors of La N /Yb N , Th/Ta, Yb N , Sr N /Nd N , and Pb N /Ce N can clearly discriminate the tectonic settings of the basalts into MORB, OIB, IAB, CRB and CFB. A radar chart containing the factors of FeO * /MgO, 10000Ga/Al, Zr+Nb+Ce+Y, Na 2 O+K 2 O/CaO, Sr, and Yb can also easily distinguish A-type granites from other types, and a radar chart containing the typical ore-forming elements can separate ore-bearing rocks from normal rocks. Meanwhile, the superiority of radar charts is also shown in their ability to simplify the discriminative process of the tectonic settings of clastic rocks and hot-water deposition characteristics according to their different features (i.e., major elements, trace elements, and their ratios), They can also be used to trace the mineral sources of ore-deposit and fluvial sediments, make comparisons between trace elements of the south Yellow Sea, contrast the differences in the mineral assemblages of shales, and identify ophiolites based on their trace elements and mineral assemblage features. However, all the factors used in the radar charts are picked based on the knowledge that has already been accepted by experts in geological field. Overall, radar charts have no fixed limitations, and they can be used flexibly. One of the significant features of radar charts is that they allow for boundless imagination and creativity, which means different researchers can design their unique radar charts based on different scientific issues. The radar chart method is just a simple method aimed at simplifying complicated scientific issues and making it easy to observe and solve problems. Although radar charts also have drawbacks (e.g., the data materials should be normalized to a certain scale and the user should possess comprehensive knowledge about the specific field), they still have promising prospects in the geosciences field and are worth being popularized.