| Wenzhangzi gold deposit locates at the eastern of Ya n-Liao fold belts in the northern of North China Plate, the contact region of Shanhaiguan uplift and western Liaoning depression. The area developed Archaeozoic metamorphic rock series, and experienced multiple tectonic magmatic activitives from Middle-Late Proterozoic to Mesozoic, to developed many fault structures, complex geological background, and superior metallogenic geological conditions.Based on analyses and studies of predecessors’ achievements, this thesis studied the characteristics of ore bodies, ores and wall rock alteration, and summarized the geological characteristics and ore-controlling regularity of Wenzhangzi gold deposits by analyzing the relationship among the formation, structure and magmatic rocks and gold mineralization; this thesis summarized metallogenic epoch, temperature, materials sources and environment of Wenzhangzi gold deposit by analyzing main elements, REE and trace elements and studying S, Pb, H and O stable isotopes and fluid inclusions; this thesis established ideal genetic model of Wenzhangzi gold deposit by studying regional metallogeny, sources of materials, metallogenic tectonic environment and regional mineralization zoning and referring to the existing deposit genetic model related to intrusions. This study determined metallogenic characteristics and genesis of Wenzhangzi gold deposit, and provided certain theoretical guidance for exploration and production as well as provided further theoretical basis for the study in western Liaoning gold deposits, and concluded the following results:(1) Lanqi Formation andesite of the middle Jurassic was the main occurrence horizon of shallow orebodies in Wenzhangzi gold deposits, and deep orebodies mainly occurred in the fracture zones within granodiorites, and the best accommodation spaces was the composite parts between the contact zone of andesites and granites and nearly EW compressive shear structural; regional circular structures related to intrusions and the existing NWW linear structures could be used as a significant channel ore-guide channel, and ore veins (bodies) mainly distributed along nearly EW compressive shear fracture tectonic belts, and they were discontinuity along the strike and trend Because of tectonic intumescence and swell-shrink.(2) Multivariate statistical analysis of trace element indicated that the best elements combination of front halo was As-Sb-Zn, superore halo was Au-Ag-Cu-Pb-Zn, and tail halo was Mn-V-Sr-Mo-Cr;(3) Geochemical characteristics of main elements, REE and trace elements indicated that the sources of Lanqi Formation andesite of the middle Jurassic, Yanshanian granodiorites and gold-bearing quartz veins were similar, being different manifestations of the same evolution series, and Wenzhangzi gold deposit was the final product of intermediate to acidic magmatism;(4) S isotope showed S came from deep; Pb isotope showed the characters of mixture of old Pb and lead Pb; H and O isotopes indicated that the ore-forming fluid was the mixture of magmatic water and atmospheric water, and inclusions homogenization temperature (169.4-238℃) showed that mineralization temperature was low-middle;(5) Comprehensive studies showed Wenzhangzi gold deposit a low-middle temperature hydrothermal deposit related to Yanshanian intermediate to acidic magmatic-hydrothermal activities, and ore-forming materials came from basic-ultrabasic gold-iron construction forming from Archean mantle-derived eruption, and metallogenic epoch was the middle-late Yanshan movement(129.81-136.16Ma), and metallogenic environment was the tectonic system transition period of North China Plate. |
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