Abstract:

Taking the Linjiasandaogou and Xiaotongjiapuzi gold (silver) deposits as examples, authors systematically summarize the metallogenetic conditions and geological characteristics of gold (silver) mineralization in the region. Fluid inclusions and stable isotope composition in the intrusion related to the deposit, wall rocks and ores are also analyzed. The results show that gold deposits in this area mainly occur in the clastic-carbonatite formation of the 6th rock segment in the Yangjiagou Formation of the Dashiqiao Sub-Group, and the Tangjiagou Formation clastic of Gaixian Sub-Group. Ore-hosting rocks mainly include silicated marble, leptynite and schist. Types of wall-rock alteration include silication, sericitization, pyritization and carbonatization. Such gold minerals as native gold mostly occur as microscopic and invisible gold minerals. Both homogenization temperature (100-200℃) and salinity (w(NaCl)=1.91%-9.73%) of mineralizing fluids are low. The δD values of oreforming fluids in the quartz from the ore change from -48.0‰ to -93.0‰, and the calculated values of δ¹⁸O_H2O from -8.63‰ to +1.31‰, which shows that the mineralizing fluid was derived from the geothermal water and connate water. The mean value of sulfur isotope (δ³⁴S) in the ore is +8.61‰，and those of ore-hosting rocks and metallogenetic intrusion vary from -8.63‰ to +1.31‰, which indicating that most of the sulfur in minerals are from Paleo-Proterozoic strata and Late Indosinian intrusion; the values of ²⁰⁶Pb/²⁰⁴Pb,²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb in gold (silver) ores are 17.664-19.186 7, 15.044-15.883 and 37.693-38.748, respectively. The Pb  has the mixing source of crustal materials with mantle components. The gold (silver) mineralization in Linjiasandaogou-Xiaotongjiapuzi area can be defined as sedimentary metamorphic magmatic hydrothermal superimposed deposit.

Key words: eastern Liaoning, Linjiasandaogou-Xiaotongjiapuzi, gold deposits, metallogenic characteristics, petrogenesis, sedimentary metamorphic-magmatic hydrothermal superimposed deposit