3b) and gold mineralization mainly occurs with silicification and pyritization
. Altered rock type is strongly associated with intense silicification, pyritization
, chloritization and illitization and its protolith are commonly volcanic breccia and tuff (Fig.
During the early stage of the diagenetic period, recrystallization of quartz and extensive pyritization
took place and the purple sandstone was discolored and changed into the light grey sandstone zone in the red-bed type copper deposits, Chuxiong basin.
Crystallographic and chemical variations during pyritization
in the upper Barremian and lower Aptian dark claystones from the Lower Saxonian Basin (NW Germany): Sedimentology, 37, pp.
of the coastal sediments in the Kelantan plains in the Malay peninsula during the Holocene.
Volcanic tuffs also show alterations and plant remains show pyritization
. At the site of uranium mineralization no color or mineral change occurs.
These facies revealed the signs of diagenetic alteration caused by the micritization dissolution cementation pyritization
recrystallization physical and chemical compaction and fracturing.
The brown colour of the burrow cover may be caused by pyritization
Huerta-Diaz MA, Morse JW (1992) Pyritization
of trace metals in anoxic marine sediments.
The mineralizations are silicification, ferritization, pyritization
, malachitization, and chalcopyritization.
of a thick zone that has taken place beneath an erosion surface may represent a significant hiatus associated with the erosion event .
Roychoudhury AN, Kostka JE, Van Cappellen P (2003) Pyritization
: a palaeoenvironmental and redox proxy reevaluated.