新疆尼勒克县松湖铁矿床黄铁矿的特征和微量元素地球化学  

Characteristics and trace element geochemistry of pyrite from the Songhu iron deposit, Nilek County, Xinjiang, China

作　　者：单强[1] 张兵[2] 罗勇[1,3] 周昌平[2] 于学元[1] 曾乔松[1] 杨武斌[1,3] 牛贺才[1] 

机构地区：[1]中国科学院广州地球化学研究所,广州510640 [2]新疆维吾尔自治区地质矿产勘查开发局第七地质大队,乌苏833000 [3]中国科学院研究生院,北京100049

出　　处：《岩石学报》2009年第6期1456-1464,共9页Acta Petrologica Sinica

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-YW-107);"十一五"国家科技支撑计划(2006BAB07BO2-03)资助.

摘　　要：松湖铁矿床位于阿吾拉勒地区东部,矿体呈层状产在石炭系阿吾拉勒组火山岩-火山碎屑岩建造中。微量元素地球化学特征显示,松湖铁矿床赋矿围岩形成于岛弧构造环境。松湖铁矿床含有草莓黄铁矿、他形-半自形黄铁矿(含有大量黄铁矿化生物遗骸)和钴黄铁矿三种不同成因的黄铁矿。铁成矿前沉积成因草莓黄铁矿受成矿热液影响发生重结晶,其钴含量及Co/Ni比值明显增大。铁成矿期的他形-半自形黄铁矿和伴生的黄铁矿化生物遗骸具有相对较高的钴含量和Co/Ni比值,显示其成矿流体与火山活动有密切的成因联系,松湖铁矿床后期叠加了铜-钴矿化作用,形成了大量的黄铜矿和钴黄铁矿。钴黄铁矿的钴含量>1%,Co/Ni比值>26,显示该矿床铜、钴的富集过程与后期火山作用有关,该矿床是一个与火山岩有关的沉积型铁矿床,其形成温度为270～325℃。The Songhu iron deposit is located in the eastern part of Awurale region, and its bed-like orebodies occurred in the voleanic-pyroclastic rocks of the Lower Carboniferous Awurale Formation. The volcanic rocks, as the wall/host rocks of the deposit, were formed in an island arc tectonic setting according to their trace element geochemistry. Three genetic types of pyrite have been distinguished in the deposit: the framboidal, the anhedral-subhedral ( with a large amount of pyritized bio-remains), and the cobalt pyrite. The pre-iron ore framboidal pyrite of sedimentary origin recrystallized due to the reworking of ore-forming hydrothermal solution, accompanied by the apparent increasing of its Co content and Co/Ni ratio. The iron ore-stage anhedral-subhedral pyrite and associated pyritized bio-remains possess relatively higher Co contents and Co/Ni ratios, indicating the close relationship between the ore-forming fluid and the magmatic (volcanic) activities. The Songhu iron deposit was superimposed by late stage Cu-Co mineralization, in which a large amount of chalcopyrite and cobalt pyrite were formed. The Co content of cobalt pyrite can be over 1% and its Co/Ni ratio over 26. It is suggested that the process of Cu-Co enrichment in the deposit is closely related to the latter stage of volcanic activity, This deposit could be recognized as a volcanic exhalative sedimentary iron deposit, and its ore-forming temperature ranges from 270 degrees C to 325 degrees C.

关 键 词：松湖铁矿床 黄铁矿 钴含量 Co/Ni比值 火山活动 

分 类 号：P618.31[天文地球—矿床学]