The pyrite is related to sericitization
, the sphalerite is related to kaolinization and seritization, and the galena is related to chloritization and epidotization (Figure 5).
Plagioclase crystals show various degrees of sericitization
, but some display relict zoning and twinning (Fig.
The mineral composition of the main components in rocks adds no information: total sericitization
and regenerational displacement of quartz in the final lithification process mask the primary characteristics of rock formation.
In active orogenic belt hydrothermal fluids alter feldspar and plagioclase into extremely fine grained quartz and mica in the form of muscovite or sericite by sericitization
while the same fluids alter biotite and garnets into chlorite by chloritization.
Often is this alteration accompanied by sericitization
and argilization of plagioclase.
It originated by massive sericitization
These features likely reflect hydrothermal alteration (e.g., silicification, sericitization
, and chloritization), as indicated by petrographic observation, and are not the result of magmatic fractionation.
continues into the orebody and K-silica alteration is sometimes developed in association with high grade ore.
Wall-rock alteration is intense and consists of silicification, sericitization
, chloritization, carbonatization, and kaolin, followed by epidotization with pyrophyllite.
Albitization and sericitization
of plagioclase led to the mobilization of Ca whereas elevated concentrations of K and Ba seem to be related to the newly formed hydrothermal K-feldspar.
The hydrothermal alterations associated with Ag-Pb-Zn mineralization in the Zhijiadi deposit mainly include silicification, carbonation, sericitization
, and chloritization.
Within the Central Zone, Main Stage veins are enclosed by broad envelopes of pervasive sericitization
with silicification immediately adjacent to the veins.