However, some hydrothermal alterations like saussuritization and sericitization
are observed in these rocks on small scale.
, hematization, argillitization and chloritization alterations are observed in wall rocks around mineralizations (Table 2).
As uranium start to deposit in reducing environment so the plant remains in host rocks are replaced by iron oxides and other minor alterations like argillization, sericitization
, calcitization, sulfidization, zeolitization, baritization etc.
The samples differ in their degree of sericitization
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.
The clay mineral suite and the clay contents are consistent with feldspar alteration mechanisms associated with sericitization
Laterally extensive sericitization
and chloritization affect the Contact Unit's basal footwall breccia.
Hydrothermal alteration in the Big Chief area is limited to weak sericitization
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
, and chloritization), as indicated by petrographic observation, and are not the result of magmatic fractionation.