A study of diamond indicative minerals in the depth and periphery of Xiyu, Mengyin County, Shandong Province: Metallogenic properties of kimberlite predicted by diamond indicating minerals

The garnet, chromite and chromic diopside in kimberlite are important indicative minerals in search for diamond deposits. According to the content of the indicative minerals, the existence and ore-bearing potential of the primary diamond deposits in kimberlite can be roughly deduced. Group G10 in garnet shows the existence of diamond in kimberlite. The higher the content is, the higher the diamond grade in the rock mass is. From G10_Xiyu% ＜ G10_Changma%, we can infer C_Xiyu＜C_Changma, and the fact proves that it is true; chromite of Group S1, S2 and S6 are associated with diamond, and chromite of Group S6 with 62 and Group S7 with 1 in Xiyu mining area is related to deep source xenoliths peridotite, which is almost from kimberlite, and has important indication significance; The more the content of chromic diopside with Cr₂O₃ ≥ 1.2% is, the higher the diamond grade is. By statistical analysis, the content of Cr₂O₃ ≥ 1.2% in surface chrome-diophanite is slightly greater than that of deep rock pipe, and the average grade of the deep orebody in Xiyu mining area is slightly lower than that in the surface orebody, which shows that the ore-bearing potential of kimberlite can be qualitatively deduced by chromic diopside. In combination with the geological work of CSAMT and drilling, the primary diamond deposits were found below-205m in the deep of the Xiyu rock pipe group, the Red Flag 15-1 rock veins were found in the periphery through the channel exploration projects, and 18 diamonds were obtained in the selection of ore samples. This proves the effectiveness and feasibility of qualitatively predicting the metallogenic properties of kimberlite with the method of indicative minerals of diamond.