黑龙江鹿鸣钼矿床地质特征及成矿年龄

Geological characteristics and ore-forming age of Luming Mo deposit in Heilongjiang Province

黑龙江鹿鸣钼矿床位于小兴安岭-张广才岭多金属成矿带翠宏山-二股成矿亚带中南段。矿化发生在花岗岩体内，矿石为石英细脉浸染状的花岗斑岩、二长花岗岩，围岩蚀变具有岩浆热液蚀变的分带特征。成矿作用与花岗岩浆侵入活动密切相关，矿床成因类型为斑岩型。岩石地球化学研究表明，矿区花岗斑岩、二长花岗岩具有同一岩浆来源，属于“A”型花岗岩，是在伸展大地构造环境背景下岩浆侵入形成的岩体。通过锆石SHRIMPU—Pb年龄测定，获得二长花岗岩年龄为（201．1±3．90）Ma和（176．2±4．3）Ma，获得花岗斑岩年龄为（182．3±4．0）Ma，确定鹿鸣钼矿床的成矿年龄在182～176Ma之间，成矿时代为燕山早期。

The Luming molybdenum deposit is located in the middle-south segment of the Cuihongshan-lc.rgu ore- forming subbelt along the Xiao Hinggan Mountains-Zhangguangcai Mountain polymetallic belt. Mo mineralization occurs in granitic pluton and monzonitic granite, and wall rock alterations are characterized by zoning of magmatic hydrothermal alterations. Mineralization is closely related to the intrusion of granitic magma. The ore deposit is genetically of the porphyry type. Petrogeochemical studies show that the granite porphyry and the monzonitic granite have the same magmatic source and belong to ＂A＂-type granite, formed by magmatic invasion in the background of stretching geotectonic environment. SHRIMP U-Pb dating yielded the age （201.1 ± 3.90） Ma and （176.2 ± 4.3） Ma for monzonitic granite and （182.3 ± 4.0） Ma for granite porphyry, suggesting that the Luming Mo deposit was formed between 182 and 176 Ma, belonging to Early Yanshanisn period.