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现代地质 ›› 2025, Vol. 39 ›› Issue (03): 598-611.DOI: 10.19657/j.geoscience.1000-8527.2025.032

• 机器学习与矿物学应用 • 上一篇    下一篇

黑龙江争光金矿床角闪辉长岩锆石U-Pb定年、Hf同位素组成及找矿意义

刘宝山1(), 寇林林1,*(), 李成禄2, 王泽宇1, 罗建2, 张春鹏1, 杨元江2, 韩仁萍1   

  1. 1.中国地质调查局沈阳地质调查中心,辽宁 沈阳 110034
    2.黑龙江省自然资源调查院,黑龙江 哈尔滨 150036
  • 出版日期:2025-06-10 发布日期:2025-07-03
  • 通信作者: *寇林林,女,正高级工程师,1983年出生,主要从事矿产地质调查及综合研究工作。Email:koulinlin@126.com
  • 作者简介:刘宝山,男,正高级工程师,1970年出生,主要从事地质矿产调查及成矿规律研究工作。Email:liubaoshan1111@163.com
  • 基金资助:
    中国地质调查局项目“大兴安岭成矿带战略性矿产调查”(DD20240061);“东北地区铜金稀有金属战略性矿产地质调查”(DD20230028)

Zircon U-Pb Dating, Hf Isotope Composition and Prospecting Significance of Diorite Porphyry in the Zhengguang Gold Deposit, Heilongjiang Province

LIU Baoshan1(), KOU Linlin1,*(), LI Chenglu2, WANG Zeyu1, LUO Jian2, ZHANG Chunpeng1, YANG Yuanjiang2, HAN Renping1   

  1. 1. Shenyang Geological Survey Center, China Geological Survey, Shenyang, Liaoning 110034, China
    2. Research Institute of Regional Geological Survey of Heilongjiang, Haerbin, Heilongjiang 150036, China
  • Published:2025-06-10 Online:2025-07-03

摘要:

通常中基性脉岩与金矿床有着密切的成因关系,正确认识二者的联系,对找矿勘查有着一定的指示意义。争光角闪辉长岩隐伏产于争光金矿区,位于大兴安岭东坡多宝山矿集区内。通过开展锆石U-Pb定年及Hf同位素组成分析,获得角闪辉长岩锆石年龄为(117.3±2.4) Ma,并存在两组(468~484) Ma和(489~550) Ma的捕获岩浆锆石年龄,指示岩脉形成于早白垩世。锆石Hf 同位素显示εHf(t)= -2.33~12.78,样品投点落于大兴安岭早白垩世火山岩带范围内,Hf 同位素数值变化较大,以正值为主,与来源于幔源岩浆经地壳物质加入的混染有关,fLu/Hf为-0.96~-0.90,二阶段模式年龄集中在533~1316 Ma。轻、重稀土分馏明显,曲线右倾,Nb、Sr、Zr亏损,Th、Ta、Nd富集,Zr(26.6×10-6~35.8×10-6)、Hf(1.39×10-6~2.08×10-6)、Cr(102×10-6~360×10-6)含量变化及La/Nb(142.5~214.8)、Zr/Ba(0.16~0.19)比值特征反映出幔源岩浆特点,形成于伸展的构造背景。角闪辉长岩与嫩江—黑河成矿带三道湾子等金成矿作用及与成矿相关的闪长质脉岩形成同一时期(110~125) Ma,同处于伸展环境,暗示该脉岩对争光矿区调查早白垩世金成矿作用具有一定的指示作用。

关键词: 角闪辉长岩, 锆石U-Pb定年, Hf同位素, 金矿床, 大兴安岭, 黑龙江

Abstract:

Mafic-ultramafic dykes often have a close genetic relation with Au deposit.Properly understanding this relationship can provide a centain degree of guidance for mineral-prospecting.The concealed hornblende gabbro of Zhengguang is located within the Zhengguang gold mining area, situated on the eastern slope of the Greater Khingan Mountains in the Duobaoshan ore concentration district.Through conducting zircon U-Pb dating and Hf isotope composition analysis, the age of the hornblende gabbro zircon was determined to be (117.3±2.4) Ma. Additionally, two groups of captured magmatic zircon ages were identified, ranging from (468-484) Ma and (489-550) Ma, indicating that the dike was formed during the Early Cretaceous period.The zircon Hf isotopes exhibit εHf(t) values ranging from -2.33 to 12.78. The sample data points fall within the range of the Early Cretaceous volcanic rock belt of the Greater Khingan Mountains. The Hf isotope values show significant variation, predominantly positive, which is associated with contamination from mantle-derived magma mixed with crustal materials. The fLu/Hf ratios range from -0.96 to -0.90, and the two-stage model ages are concentrated between 533 and 1316 Ma.The light and heavy rare earth elements show significant fractionation, with the curve leaning to the right. There is depletion in Nb, Sr, and Zr, while Th, Ta, and Nd are enriched. The contents of Zr (26.6×10-6-35.8×10-6), Hf (1.39×10-6-2.08×10-6), and Cr (102×10-6-360×10-6) vary, and the ratios of La/Nb (142.5-214.8) and Zr/Ba (0.16-0.19) reflect characteristics of mantle-derived magma, indicating formation in an extensional tectonic setting. The hornblende gabbro and the gold mineralization in the Nenjiang-Heihe metallogenic belt, such as that in the Sandaowanzi area, as well as the dioritic dikes associated with mineralization, were formed during the same period (110-125 Ma) and under similar extensional tectonic settings. This suggests that these dikes may serve as indicators for the Early Cretaceous gold mineralization in the Zhengguang mining area.

Key words: diorite porphyry, zircon U-Pb dating, Hf isotope, gold deposit, Greater Khingan Mountains, Heilongjiang Province

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