江西新余式铁矿田变质作用基本特征
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摘要
江西新余式硅铁质沉积变质铁矿分布于华南加里东造山带北缘,扬子陆块东南缘的逆冲推覆变质岩带内。本文对以往勘查中涉及较少的铁矿床变质作用特征进行研究,介绍了新余式铁矿田含铁岩系变形特征、含铁岩段变质岩石特征、含铁岩系变形与变质作用的相关性以及铁矿形成的过程,认为其原始含铁岩层主要来源于晋宁期形成的古陆块,活动大陆边缘裂陷海槽复理石沉积及海底火山活动提供了部分铁质。原始含铁岩段的铁矿物由下而上随岩类的演变呈现由镜铁矿→磁铁矿→菱铁矿→黄铁矿相序及其变化,主要受沉积时水体深度不同所产生介质的Ph、Eh条件支配,形成从氧化至还原环境的制约所致。含铁岩段经区域变质形成强度规模不等的四期变形,产生多起褶皱叠加并伴随变质作用,低温动力变质变形形成的绿片岩相变质与铁矿成矿关系最为密切。
The Xinyu type ferrosilicine diagenetic metamorphic iron deposit in Jiangxi Province is distributed at the the north margin of Caledonian orogenic belt and in the overthrust metamorphic belt at the southeast margin of Yangtze continental block. This paper studies the characteristics of metamorphism of the iron deposit that have been few dealed with in the previous prospecting, and introduces the deformation features of iron-bearing formation, features of metamorphic rocks of iron-bearing members, interrelation between deformation and metamorphism of the iron-bearing formation and the formation process of iron deposit. It is considered that the primary iron-bearing strata mainly originated from the ancient continental block formed in Jinning period, the flysch sedimentary formation of the rift trough at the active continental margin and submarine volcanic activities also provided part of iron-bearing materials. The iron minerals in the primary iron-bearing members present a phase sequence as specularite-magnetite-siderite-pyrite from below with the variation of rock types, indicating a control by pH and Eh conditions at different water depths during sedimentation caused by variation from oxidation to reducing environment. The iron-bearing members experienced regional metamorphism causing to show four stages of deformation with different intensities and scales, and to produce multiperiodic superimposed folds accompanied by metamorphism, the greenschist facies metamorphism resulted from the low-temperature dynamic metamorphic deformation is most closely related with the iron ore desormation.
The Xinyu type ferrosilicine diagenetic metamorphic iron deposit in Jiangxi Province is distributed at the the north margin of Caledonian orogenic belt and in the overthrust metamorphic belt at the southeast margin of Yangtze continental block. This paper studies the characteristics of metamorphism of the iron deposit that have been few dealed with in the previous prospecting, and introduces the deformation features of iron-bearing formation, features of metamorphic rocks of iron-bearing members, interrelation between deformation and metamorphism of the iron-bearing formation and the formation process of iron deposit. It is considered that the primary iron-bearing strata mainly originated from the ancient continental block formed in Jinning period, the flysch sedimentary formation of the rift trough at the active continental margin and submarine volcanic activities also provided part of iron-bearing materials. The iron minerals in the primary iron-bearing members present a phase sequence as specularite-magnetite-siderite-pyrite from below with the variation of rock types, indicating a control by pH and Eh conditions at different water depths during sedimentation caused by variation from oxidation to reducing environment. The iron-bearing members experienced regional metamorphism causing to show four stages of deformation with different intensities and scales, and to produce multiperiodic superimposed folds accompanied by metamorphism, the greenschist facies metamorphism resulted from the low-temperature dynamic metamorphic deformation is most closely related with the iron ore desormation.
引文
[1]吴富江,张芳荣.华南板块北缘东段武功山加里东期花岗岩特征及成因探讨[J].中国地质,2003,30(2):166-171.
[2]杨明桂,王发宁,曾勇.江西北部金属成矿地质[M].北京:中国大地出版社,2004:12-13.
[3]汤家富,许温复.变质岩构造形迹图册[M].北京:地质出版社,1987:8-12.
[4]何起祥.沉积岩和沉积矿床[M].北京:地质出版社,1987:127-130.
[5]沈其韩.变质矿床成因分类讨论[J].高校地质学报,2007,13(3):371-382.
[6]江西省地质矿产局.江西省区域地质志[M].北京:地质出版社,1984:635-636.
①赣西地质调查大队,江西省新余市良山铁矿区中深部接替资源勘查启示,2010。
①长春地质学院《全国变质图件编制与研究》论文集,1981(内部资料)。
②江西省地质矿产局,江西省区域矿产总结,1989(内部出版)。
[2]杨明桂,王发宁,曾勇.江西北部金属成矿地质[M].北京:中国大地出版社,2004:12-13.
[3]汤家富,许温复.变质岩构造形迹图册[M].北京:地质出版社,1987:8-12.
[4]何起祥.沉积岩和沉积矿床[M].北京:地质出版社,1987:127-130.
[5]沈其韩.变质矿床成因分类讨论[J].高校地质学报,2007,13(3):371-382.
[6]江西省地质矿产局.江西省区域地质志[M].北京:地质出版社,1984:635-636.
①赣西地质调查大队,江西省新余市良山铁矿区中深部接替资源勘查启示,2010。
①长春地质学院《全国变质图件编制与研究》论文集,1981(内部资料)。
②江西省地质矿产局,江西省区域矿产总结,1989(内部出版)。
目录