摘要
智博铁矿是阿吾拉勒铁铜成矿带成矿作用演化的典型代表。本文在详细的野外地质调查和室内研究的基础上,将该矿床的成矿阶段划为岩浆成矿期和热液成矿期两个期次,并将其矿石产状类型划分为块状矿石、浸染状矿石、角砾状矿石、网脉状矿石等。本文选取智博铁矿两期磁铁矿单矿物作为研究对象,通过其稀土微量元素及氧同位素等特征的研究来查明该矿床成矿物质特征及其来源。研究表明,智博铁矿的两期磁铁矿微量元素特征具有一定差异性,岩浆型磁铁矿相对富V、Ni、Ga等元素,而热液型矿石中相对富Co,贫V、Ni。两期磁铁矿单矿物稀土配分模式与矿区火山岩接近,暗示成矿物质与火山岩同源;Y/Ho比值接近球粒陨石,在Y/Ho-La/Ho图中和(La/Sm)_N-(La/Yb)_N图中,两期磁铁矿表现出同源性,暗示矿区内多数矿石的形成与火山岩浆作用有关。岩浆期的磁铁矿δ^(18)O值平均为3.4‰,与基鲁纳型铁矿和拉科铁矿的磁铁矿δ^(18)O非常接近;而热液期的磁铁矿δ^(18)O值平均为4.1‰,比岩浆期磁铁矿的δ^(18)O值范围更大些,可能与热液流体参入及矿物重结晶等因素有关。磁铁矿的地球化学特征及氧同位素均暗示智博铁矿矿石的形成主要与火山-岩浆活动密切相关,但也受到后期热液活动的影响。
The Zhibo iron deposit is a typical ore deposit found in the Awulale iron-copper metallogenic belt,as the representative product of its mineralization. Based on detailed field geological investigation,mineralogy and petrology studies,the metallogenic process of this deposit is divided into two stages,namely the magmatic mineralization and the hydrothermal mineralization. The ores in this deposit can be specifically divided into the massive ore,the disseminated ore,the brecciated ore and the reticular ore,etc. In this paper,the magnetite grains from the two mineralization phases in this deposit are selected to study the contents of their trace elements and oxygen isotopes in order to find out the characteristics and sources of the metallogenic materials. Obvious differences in the contents of trace elements in these two stages of magnetites in the Zhibo iron deposit exist： the magmatic magnetite is relatively rich in V,Ni,Ga; while the hydrothermal ore rich in Co,and poor in V and Ni. The REE distribution patterns of the magnetites from both of the two metallogenic stages are similar to those from the volcanic rocks in the mining area. The Y/Ho ratios in the magnetites are close to the values in chondrites. Furthermore,the Y/Ho-La/Ho and（ La/Sm）_N-（ La/Yb）_N diagrams show that magnetites of these two phases has the same origin,with most magnetites in the mining area having a genesis of volcanic magmatism. The averaged δ^（18）O value of magnetites from the magmatic period is 3. 4‰,which is very close to those of the magnetites of the Kiruna-type and the Laco iron deposit. While the mean δ^（18）O value of the magnetites from the hydrothermal period is 4. 1‰,larger than that of the magmatic magnetites,which may be resulted from influences caused by such factors as fluid involvement and mineral recrystallization. The geochemical characteristics and oxygen isotopes of magnetites indicate that the formation of the Zhibo iron ore is closely related to volcano-magmatism activities and it may also be affected by late stage hydrothermal activities.
作者
王志华
侯岚
高永伟
张振亮
蒋宗胜
张作衡
WANG ZhiHua;HOU Lan;GAO YongWei;ZHANG ZhenLiang;JIANG ZongSheng;ZHANG ZuoHeng(MLR Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposit,Xi＇ an Center of Geological Survey,CGS,Xi＇ an 710054,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2018年第8期2312-2326,共15页
Acta Petrologica Sinica
基金
国家自然科学青年基金项目(41402079、41603050、41602096)
国土资源部公益性行业科研专项课题(201211073-02)
国家重点基础研究发展计划(2012CB416803)联合资助 在野外地质调查研究过程中得到了新疆地质矿产勘查开发局、第三地质大队智博铁矿项目组成员以及和静县凯宏矿业有限公司的大力支持和帮助
审稿专家及编辑部俞良军老师提出许多宝贵意见
在此一并表示衷心的感谢.
关键词
智博铁矿
地球化学
氧同位素
西天山
Zhibo iron deposit
Geochemistry
Oxygen isotopes
Western Tianshan
