Abstract:

The Daping gold deposit,Yunnan,is dominantly hosted by diorite.From the distal wallrock to the vein,alteration zonings of autometamorphic diorite,choritization and carbonatization form.The later two zones are closely related to g old mineralization,gradually changing with different  width.SiO2,Al₂O₃,Na₂O,FeO,Fe₂O₃,MnO,CaO,MgO,H₂O+,Li,W,Ta,Zr,V,Sc,Sn,Mo,Cr,Co,Ni,Cu,Pb,Au and LREE decrease in chloritization zone; in contrast,K₂O,P₂O₅,Ba,HREE (including Y),Ag and Zn increase. In the carbonat izat ion prosess,SiO₂,Al₂O₃,Na₂O,K₂O,Ba,HREE(including Y),Mo,Sn,Pb,Zn and Ag are taken out;FeO,Fe₂O₃,MnO,CaO,MgO,H₂O⁺,P₂O₅,Li,Ta,Zr,V,Sc,Cr,Co,Ni,Au and LREE are taken in;W and Cu are basically unchanged.δ¹⁴C,(⁸⁷Sr/⁸⁶Sr),∈Nd (0) and fSm/Nd of the ferro dolmite of the ore vein are separately -4.81‰ which is near to the value of deep carbon,0.709019±72,-17.34 and -0.34,indicating a derivation of crust.Thestronger the rock is altered,the bigger the δ¹⁸O of the rock is,by that means the altering hy drothermal fluid is not meteoric,The value range of δ³²S of sulfides (including pyrite,galena,chalcopyrite and blende) is between -4.0 to -11.1‰ the Σ³⁴S of the hydrothermal fluid increases from early mineralization stage to late stage.

Key words: Wallrork alteration, Isotopes, Gold deposit