GEOCHEMISTRY OF THE XIAOXINANCHA GOLD-COPPER DEPOSIT IN JILIN PROVINCE

The Xiaoxinancha gold-copper deposit in Hunchun, Jilin Province is of a large-sized epithermal gold-copper associating type, jointly controlled by intrusive rocks, strata and structures, with superimposed enrichment. The orefield consists of southern section and northern section. The mineralization is developed mainly in the NNW-trending fault belt and the contact zone of intrusive rock in diorite and plagiogranite, as Au-Cu-bearing quartz sulfide veins and closely spaced veinlets. The stream sediment anomalous elements are Au, Cu, Ag, Bi, Zn, Mo and/or W, Sb, As. Soil anomalous elements include Cu, Mo, Au, Ag and Bi. The lithogeochemical anomalies involve the elements of Au, Cu, Ag, Bi, Ta, Ba, Sr and/or As, Sb, Zn, Co, Ni, W, Mo. The vertical zonation series of primary halo are presented as (Bs, Sr) -As-Ag-Pb-SnW-Au-Bi-Cu-Sb-Co-Te-Ni-Zn-Mo. The horizontal zonation series of primary halo in the southern section are shown as AuCu-Bi-Te-Ag-Pb-Zn-As-Co-Ni-W-Sb-Mo-Sn; while those in the northern section, Au-Cu-Bi-Te-Ag-As-Sb-Mo-Pb-Zn-CoW-Ni-Sn. The geochemical characteristics of the deposit and the zonation of anomalies indicate that the denudation in the northern section is greater than that in the south. The orebodies in the northwest of the orefield is more greatly denudated than in the southeast, suggesting a prospecting potential in the south of the orefield.