Geological Characteristics Of Magmatites And Their Relationship With Epithermal Gold Deposit In Northern，Heilongjiang

The research work studies in this dissertation studies the geological characteristics,petrography, geochemical characteristics, Characteristics of oxygen fugacity, andtectonic setting of the Mineralization-related magmatic rocks in the EasternHeilongjiang Sandaowanzi, Dongan, wulaga gold. the main conclusions and originalaspects of the present dissertation are summarized as follows:（1）Magmatic rocks are considered to be I-type, high K, calc-alkali granites, andrich in large lithophile elements such as Rb、Th、U、K, depleted in high strengthelements as Nb、Ta、P、Ti、HREE, with a weak abnormity in Eu（;2）LA-MC-ICPMSzircon U-Pb results show that the diagenetic age of magmatic rocks can be dividedinto two areas：Early Mesozoic(190～160Ma), Affected by the subduction of thePacific Ocean, Diagenetic time earlier than mineralization. Adamellite ofSandaowanzi is considered to be type I to type A transitional granite and age is188.2±0.6Ma. Coarse grain alkali granite of Dongan is considered to be late-orogenicgranitic rocks and age is187.2±0.6Ma. The late Mesozoic, the diagenesis andmineralization occurs after the closure of the paleo Asian Ocean, intra continentalextensional environment. Mineralization ages of Sandaowanzi, Dongan, wulaga areconcentrated in the120～100Ma. The age of active continental margin arc type Igranodiorite of Wulaga is107.74±0.4Ma, fine grained alkali granite of Dongan isconsidered to be post-orogenic granitic rocks (3) Adamellite of Sandaowanzi formedearlier than mineralization，Alkali granite of Dongan is the surrounding rock of goldmine, The two stages of alkali granite intrusion are conducive to the enrichment andmineralization of gold. Granodiorite of Wulaga is the metallogenic geological body,provides some ore-forming materials. Distribution patterns of the rare-earth elementin magmatic rocks and ores likeness, speculate that they are homologous magmaticrocks.（4）Magma in the strong oxidation (lg (O2)=-9.4～-14.59), hightemperature (T=680℃～863℃) environment, the range of Oxygen fugacity inMH-FMQ(Magnetite-hematite-fayalite-magnetite-quartz), High Ce abnormity inzircon and Eu negative anomaly in the trace elements of whole rock, also reflect thatthe diagenetic physical and chemical conditions is in oxidizing environment, I typegranite with high oxygen fugacity is beneficial to the formation of the Au mine.