## 5 Discussion
### Exploration Significance  
According to the results of SWIR spectroscopy, the mineralized area in this study mainly involved illitization and chloritization. They are widely distributed in andesite, andesitic crystal tufaceous breccia, gabbroic diorite, and diabase of the study area. In borehole ZK2115-1, Pos2200 exhibited a steady change, in which the Al-OH absorption peak at 122.5-128.35 m had a slight tendency to decrease. At the depth ranges of 122.5-128.35 m, 200 m, and 300-350 m, the illite's crystallinity index was greater than 1.0, while the chlorite's crystallinity index was greater than 3.0 when the depth ranges were 122.5-200 m and 350 m (Figure 11, left). At the 122.5-128.35 m deep mineralized zone, the primary rock was andesite. In the fractures, we found yellowish calcite-quartz veins. Along the calcite veins, we observed scattered occurrences of pyrite and sphalerite in spots, blocks, and sparsely disseminated forms. There was a strong chloritization, so the rock was fragmented. A number of calcite-quartz veins developed at 127-127.75 m, indicating a good mineralization. At 247.20-248.40 m, the lead-zinc mineralization was present, with speckled pyrite, galena, and sphalerite occurring along the calcite-quartz veins in fractures. At 257-257.7 m, the rock was loosely cemented and was made up of chloritized and illitized manganese rhodochrosite (Figure 10d), along with a network of fine-grained quartz-calcite veins. In the ZK20(0)1'02 section, muscovitic illite most probably occurred within 48.9 to 54.8 m and 80 to 86.6 m from the surface (Figure 7). At the interval of 48.9 to 54.8 m, the dominant minerals included Fe-chlorite, illite, and calcite. The 80-86.6 m interval comprised Fe-Mg chlorite, illite, and smectite (Figure 10e). The strongest mineralization occurred at the depth of 48.9 to 54.8 m, with a remarkable Pb of 29.35%, Zn of 12.14%, Ag of 301 g/t, and Cu of 0.2%. Figure 10: Photographs of major mineralization and alteration relationships in the Jiawula deposit: (**a**) smoke gray comb quartz, granular galena can be seen; (**b**) quartz vein filled with hydrothermal breccia, massive galena pyrrhotite cement, visible Fe-chlorite breccia; (**c**) yellow-green strong illite dacite porphyrite, late ferrochlorite network veins, fine-grained pyrite cluster spots can be seen along the chlorite edge; (**d**) rhodochroite and chlorite surrounding andesite; (**e**) illite and montmorillonite in the andesitic tuff in the outer zone of the ore body; (**f**) diffuse planar kaolinite in andesite. Q—quartz; Py—pyrite; Po—pyrrhotite; Gn—galena; Chl—chlorite; Ill—illite; Rho—rhombosite; Mon—montmorillonite; Kao—kaolinite. In borehole ZK13'03, Pos2200 exhibited a steady variation. However, at the depth of 120.6-137.25 m, the illite crystallinity, Pos2350, and chlorite crystallinity increased significantly (Figure 11, right). The interval from 130.15 to 135.27 m was mineralized. Its rock type was andesite, with strong chloritization, illitization, and kaolinization (Figure 10f). Fine veins of lead galena, sphalerite, and pyrite developed along the fractures. At 130.15-130.50 m, there was the development of quartz veins and abundant pyrite, lead galena, and sphalerite occurring along the fractures. They occurred in blocks and densely disseminated forms, The lead-zinc-iron mineral veins were later intersected and cut by quartz veins. From 133.18 to 134.58 m, lead galena, sphalerite, and pyrite developed along the fractures in veins or disseminated forms. According to our comprehensive analysis, the lead-zinc mineralization is closely linked to the later-stage fracturing alteration in the diabase and andesite and a high illite crystallinity index (>1.1) [6; 7; 8]. The content of Pb-Zn-Ag is generally higher when the Fe-OH absorption peak wavelength of chlorite (>2254) and the crystallinity index (>3.0) are larger [13; 14; 15; 16; 17; 18; 19; 20]. Moreover, the dominant chlorite is Fe-chlorite.