Study On Mineral Chemistry And Genesis Of Pyrite In Xiaoyingpan Tellurium Gold Deposit,Hebei Province

This study takes Xiaoyingpan gold deposit as research objectives,which is located in the Xuanhua area,Zhajiakou region,Hebei province.The origin of the deposit is still controversia.Based on the microscopic observation and backscattered electron images,the pyrites in the sulfide-polymetallic stage are divided into three types: 1)euhedral,colloidal pyrites(PyⅠ);2)euhedral and cyclic,central euhedral and external porous pyrites(PyⅡ);3)fragmented pyrites(PyⅢ).Insitu LA-ICP-MS results indicate that Ni is enriched in the PyⅠ,Zn、As contents in the PyⅠare relatively higher than PyⅡ and PyⅢ,Co,Bi,Cu,Pb,Ag contents in PyⅠare lower than those in PyⅡ,but relatively higher than those in PyⅡ,Cu,Pb,Ag,Mo are enriched in the PyⅡ,the main ore-forming elements are relatively lower in the PyⅢ other than Au;Au and Ag are formed as inclusions in PyⅠ,part of the gold are existed as sub-microscopic or nano particles,silver is formed as Ag-Au or Sb-Bi inclusions in the PyⅡ.The results show that As is always below or only marginaly higher than detection limits,and plays an insignificant role in gold mineralization,highlighting the role of Te as important scavengers in enrichment Au.There may be existed in Ag-Au microscopic inclusions or native gold particles.Porous texture is common in the PyⅡ,indicating that fluids are permeated in the PyⅡ,hydrothermal fluids bring plenty of gold and other elements,which represents the main gold deposition stage.Integrate the previous results,we can conclude that ore-forming materials are mainly mantle-origin,mantle-branch structure is the key factor controlling the ore material rising from the deep earth,while ore forming fluids are mixed dominantly by magmatic-hydrothermal origin.