CAJ | 학술논문

对安徽新桥矿床进行系统的野外地质调查和矿相学研究发现，层状矿体中的胶状黄铁矿交代矽卡岩磁铁矿矿体，为探讨层状硫化物矿床是早期沉积成因还是岩浆热液成因提供了新的地质约束。对铜陵矿集区内的新桥矿床层状菱铁矿矿体和凤凰山矽卡岩型矿体中的菱铁矿开展了 Fe 同位素组成的对比研究，结果显示：新桥矿床菱铁矿与典型低温热液脉型矿床和沉积铁矿中的菱铁矿在 Fe 同位素组成特征上有所不同，而与凤凰山矽卡岩型矿床中的菱铁矿更为接近；新桥矿床中胶状黄铁矿和菱铁矿相对于磁铁矿富集 Fe 的轻同位素，表明磁铁矿不是过去认为的由胶状黄铁矿和菱铁矿矿胚层经热液改造形成，而是与典型的岩浆热液有关。新桥矿区层状硫化物矿体和矽卡岩型矿体中，近岩体矽卡岩和最早形成的金属矿物磁铁矿比岩体更为富集 Fe 的轻同位素，而赋矿围岩比岩体更为富集 Fe 的重同位素。同时，不同矿化阶段形成的含铁矿物和不同空间位置的硫化物中的 Fe 同位素组成呈现出时空分带现象，Fe 同位素组成的时空演化特征与流体出溶、流体演化非常一致，并且符合同位素分馏的基本理论，表明层状硫化物矿体和矽卡岩型矿体具有相同的成矿物质来源，为同一流体体系演化的产物。新桥矿区岩相学的研究结果和 Fe同位素组成特征均表明，新桥层状硫化物矿床不是海西期喷流沉积成矿作用的产物，而是燕山期热液成矿作用的产物，为一个典型的热液成因矿床。
대안휘신교광상진행계통적야외지질조사화광상학연구발현，층상광체중적효상황철광교대석잡암자철광광체，위탐토층상류화물광상시조기침적성인환시암장열액성인제공료신적지질약속。대동릉광집구내적신교광상층상릉철광광체화봉황산석잡암형광체중적릉철광개전료 Fe 동위소조성적대비연구，결과현시：신교광상릉철광여전형저온열액맥형광상화침적철광중적릉철광재 Fe 동위소조성특정상유소불동，이여봉황산석잡암형광상중적릉철광경위접근；신교광상중효상황철광화릉철광상대우자철광부집 Fe 적경동위소，표명자철광불시과거인위적유효상황철광화릉철광광배층경열액개조형성，이시여전형적암장열액유관。신교광구층상류화물광체화석잡암형광체중，근암체석잡암화최조형성적금속광물자철광비암체경위부집 Fe 적경동위소，이부광위암비암체경위부집 Fe 적중동위소。동시，불동광화계단형성적함철광물화불동공간위치적류화물중적 Fe 동위소조성정현출시공분대현상，Fe 동위소조성적시공연화특정여류체출용、류체연화비상일치，병차부합동위소분류적기본이론，표명층상류화물광체화석잡암형광체구유상동적성광물질래원，위동일류체체계연화적산물。신교광구암상학적연구결과화 Fe동위소조성특정균표명，신교층상류화물광상불시해서기분류침적성광작용적산물，이시연산기열액성광작용적산물，위일개전형적열액성인광상。
Systematical field work and ore microscopy studies have been carried out in the Xinqiao deposit.The fact that the skarn-associated magnetite is cut by the colloidal pyrite in the stratiform ore body provides a new constraint on the ore genesis of the stratiform sulfide ore body in Xinqiao deposit. The Fe isotope compositions of siderite minerals from the siderite ore bodies in Xinqiao and Fenghuagnshan skarn Fe Cu ore bodies were analyzed and compared.Fe isotope compositions of the siderite from Xinqiao deposit are different from those from sedimentary and hydrothermal vein-type deposits,but similar to those from the Fenghuanghsan skarn Fe Cu deposit.Moreover,the fact that the heavy Fe isotope enrichment in magnetite related to siderite and colloidal pyrite indicates that the siderite and colloidal pyrite cannot be altered to be magnetite.Fe isotope compositions in sulfide ores, quartz-monzodiorite stock and limestone wall-rock in Xinqiao strata bound sulfide and skarn ore were examined.Theδ57 Fe values of endoskarn and the earliest formed magnetite are lower than those of the quartz-monzodiorite,while δ57 Fe values of limestone wall-rock are higher than those of the igneous stock.Moreover,such features as spatial and temporal zoning,evolution of Fe isotope are consistent with fluid exsolutionary and evolutionary theory, also accordant with basic theory of Fe isotopic fractionation,which suggests that two types of ores be resulted from the same hydrothermal fluid system and Fe element came from the same magmatic source.The Fe isotope characteristics,together with ore minerals paragenesis relationship,demonstrate that the Xinqiao Cu S Fe Au deposit is a typical hydrothermal skarn deposit,rather than the multi-stage syngenetic-hydrothermal compound deposit.