滇西北红山铜多金属矿床的成因类型:黄铁矿和磁黄铁矿LA-ICPMS微量元素制约
发布时间：2018-08-21 08:27
【摘要】：红山大型铜多金属矿床位于云南中甸地区,包括红山、红牛和恩卡3个矿段,矿体主要呈层状-似层状产于石榴石夕卡岩、角岩、大理岩和硅质岩之中,或者呈细脉浸染-网脉状赋存于深部隐伏花岗斑岩体之中。目前学术界关于该矿床的成因类型仍然存在不同认识,本文使用激光剥蚀电感耦合等离子体质谱仪(LAICPMS)对矿区硅质岩、夕卡岩矿石中的黄铁矿和磁黄铁矿进行了微区原位成分的测试,进而根据微量元素特征来约束矿床的成因。分析结果表明,不同产状的黄铁矿具有明显不同的微量元素组成,硅质岩中的黄铁矿相对富集Ti、Mn、Ni、As、Pb、Bi、Te、Ag和Sb等微量元素,Co/Ni比值小于1,表现为典型同生沉积黄铁矿的微量元素特征;而夕卡岩矿石中的黄铁矿则相对富集Co和Cu,亏损As、Se和Sb等低温元素,且Co/Ni比值多数大于1,显示高温岩浆热液黄铁矿的微量元素特征。此外,硅质岩中磁黄铁矿的Co、Ni和Se等微量元素组成与黄铁矿的组成十分类似,表明它们的化学组成主要受到沉积环境的控制。夕卡岩中的磁黄铁矿与黄铁矿相比强烈亏损Co,这可能归因于早期黄铁矿沉淀时带走了大量的Co,从而导致残余热液中Co浓度的大幅降低。通过研究,我们还查明红山矿区黄铁矿中的Co、Ni、As和Se等元素主要以固溶体的形成存在,而Pb、Bi、Ag、Cu和Mn等元素则主要以显微包裹体的形式存在。黄铁矿和磁黄铁矿中Pb和Bi均表现为正相关关系,暗示它们可能以显微包裹体或纳米微粒的形式分布于这两种硫化物中。结合野外地质产状与前人已有研究,我们认为红山矿区至少存在两期成矿作用,其中晚三叠世沉积成岩作用形成的黄铁矿富集了一定的Ag、Bi和Pb等成矿元素,而晚白垩世的岩浆-热液活动则带来了大量的Cu和Mo等金属元素,从而在红山矿区形成了复合型的Cu-Mo-Pb-Zn-Ag多金属矿化体系。
[Abstract]:The Hongshan large copper polymetallic deposit is located in Zhongdian area, Yunnan Province, including Hongshan, Hongbiu and Enka ore sections. The orebodies are mainly bedded and bedded in garnet skarn, hornstone, marble and siliceous rock. Or in the deep concealed granitic porphyry as vein-dipping-reticular veins. At present, there is still different understanding about the genetic type of the deposit in academic circles. In this paper, the siliceous rocks in the ore area are treated by laser denudation inductively coupled plasma mass spectrometer (LAICPMS). Pyrite and pyrrhotite in skarn ore were measured in situ and the origin of the deposit was restricted according to the characteristics of trace elements. The results show that the pyrite with different occurrence has different trace element composition, and the pyrite in siliceous rock is relatively enriched in TiMnPbBPbBiTE-Ag and SB, and the ratio of Co / Ni is less than 1, which shows the trace element characteristic of typical synsedimentary pyrite. The pyrite in skarn ore is relatively rich in Co and Cu, depleted in low temperature elements such as As-se and SB, and the Co/Ni ratio is more than 1, which shows the trace element characteristics of high-temperature magmatic hydrothermal pyrite. In addition, the trace element composition of pyrrhotite in siliceous rock is very similar to that of pyrite, indicating that their chemical composition is mainly controlled by sedimentary environment. Compared with pyrite, pyrrhotite in skarn has a strong loss of Co, which may be attributed to the large amount of Coin taken away during the early pyrite precipitation, which leads to a significant decrease in the concentration of Co in residual hydrothermal solution. Through the study, we also find that the elements such as Co-NiAs and se in pyrite of Hongshan mining area mainly exist in the form of solid solution, while the elements such as PbPbBBiAg-Ag-Cu and mn exist mainly in the form of microinclusions. The positive correlation between Pb and Bi in pyrite and pyrrhotite suggests that they may be distributed in the form of microinclusions or nanoparticles. In combination with the field geological occurrence and previous studies, we believe that there are at least two stages of mineralization in Hongshan ore area, in which pyrite formed by late Triassic sedimentary diagenesis has enriched some metallogenic elements, such as Agnb Bi and Pb, etc. During the late Cretaceous magma hydrothermal activity resulted in a large amount of Cu and Mo metal elements thus forming a complex Cu-Mo-Pb-Zn-Ag polymetallic mineralization system in Hongshan mining area.
【作者单位】： 中国地质科学院地质研究所;中国科学院地球化学研究所矿床地球化学国家重点实验室;
【基金】：澳大利亚塔斯马尼亚大学国家优秀矿床研究中心科研基金项目(CODES-P2A3) 国家自然科学基金项目(41373051,41003023) 中国科学院“西部之光”项目
【分类号】：P618.2
，
本文编号：2195134
[Abstract]:The Hongshan large copper polymetallic deposit is located in Zhongdian area, Yunnan Province, including Hongshan, Hongbiu and Enka ore sections. The orebodies are mainly bedded and bedded in garnet skarn, hornstone, marble and siliceous rock. Or in the deep concealed granitic porphyry as vein-dipping-reticular veins. At present, there is still different understanding about the genetic type of the deposit in academic circles. In this paper, the siliceous rocks in the ore area are treated by laser denudation inductively coupled plasma mass spectrometer (LAICPMS). Pyrite and pyrrhotite in skarn ore were measured in situ and the origin of the deposit was restricted according to the characteristics of trace elements. The results show that the pyrite with different occurrence has different trace element composition, and the pyrite in siliceous rock is relatively enriched in TiMnPbBPbBiTE-Ag and SB, and the ratio of Co / Ni is less than 1, which shows the trace element characteristic of typical synsedimentary pyrite. The pyrite in skarn ore is relatively rich in Co and Cu, depleted in low temperature elements such as As-se and SB, and the Co/Ni ratio is more than 1, which shows the trace element characteristics of high-temperature magmatic hydrothermal pyrite. In addition, the trace element composition of pyrrhotite in siliceous rock is very similar to that of pyrite, indicating that their chemical composition is mainly controlled by sedimentary environment. Compared with pyrite, pyrrhotite in skarn has a strong loss of Co, which may be attributed to the large amount of Coin taken away during the early pyrite precipitation, which leads to a significant decrease in the concentration of Co in residual hydrothermal solution. Through the study, we also find that the elements such as Co-NiAs and se in pyrite of Hongshan mining area mainly exist in the form of solid solution, while the elements such as PbPbBBiAg-Ag-Cu and mn exist mainly in the form of microinclusions. The positive correlation between Pb and Bi in pyrite and pyrrhotite suggests that they may be distributed in the form of microinclusions or nanoparticles. In combination with the field geological occurrence and previous studies, we believe that there are at least two stages of mineralization in Hongshan ore area, in which pyrite formed by late Triassic sedimentary diagenesis has enriched some metallogenic elements, such as Agnb Bi and Pb, etc. During the late Cretaceous magma hydrothermal activity resulted in a large amount of Cu and Mo metal elements thus forming a complex Cu-Mo-Pb-Zn-Ag polymetallic mineralization system in Hongshan mining area.
【作者单位】： 中国地质科学院地质研究所;中国科学院地球化学研究所矿床地球化学国家重点实验室;
【基金】：澳大利亚塔斯马尼亚大学国家优秀矿床研究中心科研基金项目(CODES-P2A3) 国家自然科学基金项目(41373051,41003023) 中国科学院“西部之光”项目
【分类号】：P618.2
，
本文编号：2195134
本文链接：https://www.wllwen.com/kejilunwen/kuangye/2195134.html
