吉林省白山市板庙子金矿床地质、地球化学特征及成因研究

发布时间：2018-09-12 09:53

【摘要】：板庙子金矿床位于白山市以北5km～8km，是目前正在勘探、开采的大型金矿床。 矿区地层有老岭群和青白口系，F102是重要控矿构造，F100是重要容矿构造。矿石矿物有自然金、褐铁矿、毒砂、赤铁矿、黄铁矿、胶状黄铁矿等；矿石具有镶边、填隙等结构；矿石构造主要有角砾状构造、浸染状构造、胶状构造、星点状构造等，围岩为硅化构造角砾岩，成矿期主要有：石英—金—黄铁矿阶段、石英—金—浸染状黄铁矿阶段、重晶石—玉髓—金—赤铁矿阶段、黄铁矿—白铁矿阶段。 与板庙子金矿成矿有关的岩体为中侏罗世花岗闪长斑岩岩体，岩石化学及岩石地球化学的研究表明，刚玉含量6.30～8.73，Al2O3含量17.27%～17.85%，A/CNK值为1.49～1.81，属于强过铝质花岗岩；全碱（Na2O+K2O）值为5.32%～5.60%，平均5.44%；里特曼指数σ=1.13～1.29，＜3.3，是钙碱性岩石；δEu为1.01～1.06，＞1，铕具正异常，表明源区富斜长石；δCe为0.72～0.82，平均0.76，＜1，具负铈异常，铈亏损型，低场强元素Rb、Ba相对富集，Sr亏损；高场强元素P、U、Sm、Th富集，亏损Ti、K，Ti相对亏损，属造山带S型花岗岩，其构造环境位于火山弧环境中，其形成与板块俯冲有密切联系。 气液两相流体包裹体多呈近圆形、椭圆形等，大小2μm～12μm之间，2μm～5μm居多，均一温度140.0℃～243.3℃，平均190.4℃，，属低温；密度0.82g/cm3～0.93g/cm3，平均值0.91g/cm3，属低密度；主成矿期压力9.64Mpa～17.91Mpa，平均值12.51Mpa；盐度1.7%NaCl～3.4%NaCl，平均盐度2.81%NaCl，属低盐度；成矿深度0.96km～1.80km，平均值1.25km，是浅成热液矿床。通过对S同位素分析表明，S来源于海相蒸发岩。 综合研究表明：板庙子金矿为燕山期与造山运动有关的浅成低温热液型矿床。
[Abstract]:Panmiaozi gold deposit is a large gold deposit which is currently under exploration and mining, which is located at 5 km ~ 8 km north of Baishan City. The strata of Laoling Group and Qingbakou system are important ore-controlling structures and F100 is an important ore-bearing structure. Ore minerals include natural gold, limonite, arsenopyrite, hematite, pyrite, colloidal pyrite, etc. The ore has rimmed and interstitial structures; ore structures are mainly breccia structure, disseminated structure, colloidal structure, star dot structure, etc. The surrounding rocks are silicified structural breccia, which are mainly composed of quartz-gold-pyrite, quartz-gold-disseminated pyrite, barite, chalcedone-gold-hematite, pyrite and albite. The ore-forming body of Banmiaozi gold deposit is the middle Jurassic granodiorite porphyry. The petrochemistry and geochemistry show that the content of corundum is 6.30 ~ 8.73% Al _ 2O _ 3 17.27 and 17.85A / CNK is 1.491.81, which belongs to strong peraluminous granite. The total alkali (Na2O K 2O) value is 5.32 and 5.60, with an average value of 5.44. the Ritman index 蟽 1.131.29, < 3.3, is calc-alkaline rock; 未 Eu is 1.01C 1.06, > 1, europium is positive anomaly, indicating that the source region is plagioclase, 未 Ce is 0.720.82 (mean 0.76, < 1), with negative cerium anomaly, cerium depletion type, 未 Ce = 0.72 0.82 (mean 0.76, < 1). The low field strength element Rb,Ba is relatively enriched with Sr depletion, and the high field strength element is rich in Rb,Ba and depleted in Ti,K,Ti. It belongs to the S-type granites of orogenic belt, and its tectonic environment is located in the volcanic arc environment, and its formation is closely related to plate subduction. The gas-liquid two-phase fluid inclusions are almost round and oval in shape, mostly in size of 2 渭 m ~ 12 渭 m ~ (2 渭 m) ~ 2 渭 m ~ 5 渭 m. The homogeneous temperature is 140.0 鈩

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