| The Zhujiawa molybdenum deposit is in Huaian County,Zhangjiakou located in the northern margin of the North China platform.It is one of the newly discovered large-scale molybdenum deposits in recent years.The deposit and the Dasuji molybdenum deposit in Zhuozi County of Inner Mongolia and CaoSiyao in Xinghe County discovered in recent years.They are all in the northwest-western Shangdu-Yuxian polymetallic metallogenic belt and have similar metallogenic conditions.However,due to the short discovery time and low degree of research,the molybdenum deposit lacks systematic analysis of the metallogenic regularity,formation age and formation mechanism of molybdenum deposits.In particular,the genetic type of the molybdenum deposit has not been clearly determined.Therefore,the study of the ore-forming type of the deposit has important practical significance for regional guidance and prospecting.Based on the existing exploration results in the mining area,the source of ore-forming materials is determined by the analysis of ore S,isotope,trace elements and rare earth elements.The ore phase and composition of the H-O isotope and fluid inclusions,formation temperature and anion and cation Component analysis is used as a means to determine the properties and sources of ore-forming fluids;the zircon U-Pb dating and molybdenite Re-Os dating are used to determine the formation time of the rock mass and ore body associated with the deposit.Based on the above-mentioned ore-forming elements,ore-forming fluid properties and sources,and metallogenic age analysis,combined with regional tectonic-magmatic evolution,mining tectonic environment,the genetic type of the deposit was determined.The S isotope and H-O isotopes of the Zhujiawa molybdenum deposit show that the ore-forming materials are mainly derived from the deep magma of the upper mantle or the lower crust,and the fluid inclusion characteristics(envelope mineralogy,temperature,salinity and composition)of the deposit show high temperature.High salinity characteristics with magma source characteristics.The trace elements and rare earth elements of the deposit show that the rock mass,the ore body and the old stratum have homology,and the H-O isotope shows some atmospheric precipitation properties,indicating that the Archean old stratum and the medium-acid rock mass provide the Zhujiawa molybdenum deposit.Mineralization material,and in the later stage of mineralization,the deposit is affected by atmospheric precipitation,and the source of ore-forming fluid is converted into a mixed source.According to the zircon U-Pb isotope and molybdenite Re-Os isotope dating results,the rock mass associated with mineralization is formed between(144.8±1.1)Ma and(157.48±0.85)Ma,and the ore body is formed at(141.7 ±2.9)Ma,both of which are continuous events and are in the Yanshanian period.According to the current analysis results,it is compared with the Caosiyao super-large molybdenum mine in Xinghe County,Inner Mongolia,and the Jiajiaying medium-type molybdenum deposit in Xuanhua County,Hebei Province.The genetic type of the Zhujiawa molybdenum deposit is a porphyry deposit.Based on this,the metallogenic model of the Zhujiawa molybdenum deposit is established and the prospecting mark is established,which provides a theoretical basis for the subsequent prospecting work. |
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