The Huxu Au-dominated polymetallic deposit is a hydrothermal deposit located in the Dongxiang volcanic basin in the middle section of the Gan-Hang tectonic belt in South China.The orebodies primarily occur within the ...The Huxu Au-dominated polymetallic deposit is a hydrothermal deposit located in the Dongxiang volcanic basin in the middle section of the Gan-Hang tectonic belt in South China.The orebodies primarily occur within the Jurassic-Cretaceous quartz diorite porphyry,while the genesis of this deposit is unclear.This study focused on geological and mineralogical characteristics,in-situ trace elements and S-Pb isotopes of three generations of pyrite of the Huxu deposit to clarify the distribution of trace elements in pyrite,ore-forming fluid and material sources,and genetic types of the deposit.The mineralization stage of the deposit can be divided into quartz-pyrite stage(S1),quartz-pyrite-hematite stage(S2),quartz-polymetallic sulfide stage(S3)and quartz-hematite stage(S4),with the corresponding pyrite being divided into three generations(Py1-Py3).in-situ trace element data of pyrite show that Au in pyrite mainly exists in the form of solid solution(Au^(+)),and the content is relatively low at all stages(0.18 ppm for Py1,0.32 ppm for Py2,0.68 ppm for Py3),while Pb and Zn mainly exist as sulfide inclusions in the pyrite.S-Pb isotopes show that the sulfur and ore-forming material of this deposit are mainly sourced from magma.The mineral association,mineral textures and trace elements in different stages of pyrite indicate that fluid boiling and fluid mixing are the key factors of native gold precipitation in S2 and S4,respectively,while water-rock interaction controlled the precipitation of Pb-Zn sulfides.These integrating with geological characteristics suggests that the deposit should be an intermediate sulfidation epithermal deposit.展开更多
西藏冈底斯成矿带分布着大面积古近纪（70—40Ma）林子宗群火山岩。但如此强烈的火山-岩浆作用，与安第斯成矿带相比（如马力昆带（FranjadeMaricunga）、印地-帕斯瓜带（Franja El Indio—Pascua）），除了碰撞伸展阶段形成的驱龙、甲...西藏冈底斯成矿带分布着大面积古近纪（70—40Ma）林子宗群火山岩。但如此强烈的火山-岩浆作用，与安第斯成矿带相比（如马力昆带（FranjadeMaricunga）、印地-帕斯瓜带（Franja El Indio—Pascua）），除了碰撞伸展阶段形成的驱龙、甲玛等斑岩-矽卡岩型铜多金属矿床外（23—13Ma），“缺位”资源规模大、经济价值高的浅成低温热液型矿床成矿亚系列。该类矿床是剥蚀了，还是没有发现？本文在前人工作基础上，通过详细的地质勘探、地质填图、地质编录、镜下鉴定、能谱和电子探针分析，在南木林盆地斯弄多地区林子宗群陆相火山岩中识别出低硫化浅成低温热液型银铅锌（铟镉金）矿床。矿体由产于流纹斑岩中的隐爆角砾岩型银铅锌矿体、火山机构旁侧的热液脉型银铅锌矿体及断裂上盘的银（铅锌）矿体组成，目前控制Pb＋Zn资源量超过30万吨（331＋332为主）@Pb＋Zn〉5％，Ag资源量超过400吨@Ag〉50g／t。主要金属矿物为方铅矿、闪锌矿、辉银矿、硫砷铜银矿、黄铁矿，微量黄铜矿，主要蚀变组合为：石英一玉髓一碧玉，重晶石．萤石，冰长石．伊利石．绢云母，菱铁矿一菱锰矿；矿石构造以脉状、角砾状、网脉状、条带状、层纹状、皮壳状、块状、浸染状等，发育结晶作用和交代作用形成的矿石结构；近地表发育古热泉喷口，堆积条带状、层纹状硅质沉积物。综合上述地质信息，确定该矿床为典型低硫化浅成低温热液型银多金属矿床。这一重要矿床类型的发现和确定在冈底斯成矿带乃至西藏特提斯成矿省尚属首例，对冈底斯成矿带广泛发育形成于70～40Ma的林子宗群火山岩地区区域找矿具有积极和重要的指导意义，其重要性不容低估。展开更多
基金jointly supported by the foundation from Department of Science and Technology of Jiangxi Province(No.20232BAB213064)National Natural Science Foundation of China(No.42102088)foundation from the State Key Laboratory of Nuclear Resources and Environment(2022NRE33)。
文摘The Huxu Au-dominated polymetallic deposit is a hydrothermal deposit located in the Dongxiang volcanic basin in the middle section of the Gan-Hang tectonic belt in South China.The orebodies primarily occur within the Jurassic-Cretaceous quartz diorite porphyry,while the genesis of this deposit is unclear.This study focused on geological and mineralogical characteristics,in-situ trace elements and S-Pb isotopes of three generations of pyrite of the Huxu deposit to clarify the distribution of trace elements in pyrite,ore-forming fluid and material sources,and genetic types of the deposit.The mineralization stage of the deposit can be divided into quartz-pyrite stage(S1),quartz-pyrite-hematite stage(S2),quartz-polymetallic sulfide stage(S3)and quartz-hematite stage(S4),with the corresponding pyrite being divided into three generations(Py1-Py3).in-situ trace element data of pyrite show that Au in pyrite mainly exists in the form of solid solution(Au^(+)),and the content is relatively low at all stages(0.18 ppm for Py1,0.32 ppm for Py2,0.68 ppm for Py3),while Pb and Zn mainly exist as sulfide inclusions in the pyrite.S-Pb isotopes show that the sulfur and ore-forming material of this deposit are mainly sourced from magma.The mineral association,mineral textures and trace elements in different stages of pyrite indicate that fluid boiling and fluid mixing are the key factors of native gold precipitation in S2 and S4,respectively,while water-rock interaction controlled the precipitation of Pb-Zn sulfides.These integrating with geological characteristics suggests that the deposit should be an intermediate sulfidation epithermal deposit.
文摘西藏冈底斯成矿带分布着大面积古近纪（70—40Ma）林子宗群火山岩。但如此强烈的火山-岩浆作用，与安第斯成矿带相比（如马力昆带（FranjadeMaricunga）、印地-帕斯瓜带（Franja El Indio—Pascua）），除了碰撞伸展阶段形成的驱龙、甲玛等斑岩-矽卡岩型铜多金属矿床外（23—13Ma），“缺位”资源规模大、经济价值高的浅成低温热液型矿床成矿亚系列。该类矿床是剥蚀了，还是没有发现？本文在前人工作基础上，通过详细的地质勘探、地质填图、地质编录、镜下鉴定、能谱和电子探针分析，在南木林盆地斯弄多地区林子宗群陆相火山岩中识别出低硫化浅成低温热液型银铅锌（铟镉金）矿床。矿体由产于流纹斑岩中的隐爆角砾岩型银铅锌矿体、火山机构旁侧的热液脉型银铅锌矿体及断裂上盘的银（铅锌）矿体组成，目前控制Pb＋Zn资源量超过30万吨（331＋332为主）@Pb＋Zn〉5％，Ag资源量超过400吨@Ag〉50g／t。主要金属矿物为方铅矿、闪锌矿、辉银矿、硫砷铜银矿、黄铁矿，微量黄铜矿，主要蚀变组合为：石英一玉髓一碧玉，重晶石．萤石，冰长石．伊利石．绢云母，菱铁矿一菱锰矿；矿石构造以脉状、角砾状、网脉状、条带状、层纹状、皮壳状、块状、浸染状等，发育结晶作用和交代作用形成的矿石结构；近地表发育古热泉喷口，堆积条带状、层纹状硅质沉积物。综合上述地质信息，确定该矿床为典型低硫化浅成低温热液型银多金属矿床。这一重要矿床类型的发现和确定在冈底斯成矿带乃至西藏特提斯成矿省尚属首例，对冈底斯成矿带广泛发育形成于70～40Ma的林子宗群火山岩地区区域找矿具有积极和重要的指导意义，其重要性不容低估。
