新疆东天山红云滩铁矿床稀土元素特征及其成因意义  

Characteristic of REE of Hongyuntan Iron Deposit in the Eastern Tianshan of Xinjiang and Its Genetic Significance

作　　者：张立成[1,2] 王义天[2] 陈雪峰[3] 马世青[3] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [3]新疆地质矿产勘查开发局第一地质大队,新疆鄯善838204

出　　处：《地球科学与环境学报》2013年第2期32-44,共13页Journal of Earth Sciences and Environment

基　　金：中国地质调查局地质大调查项目(1212011085527)

摘　　要：新疆东天山红云滩铁矿赋存于下石炭统雅满苏组火山-沉积岩系中,矿体呈层状、似层状、透镜状产出,主要受北东向、北北东向压扭性逆断层控制。本研究识别出夕卡岩期、热液期和表生期3个成矿期,进一步划分为4个成矿阶段:无水夕卡岩阶段、退化蚀变阶段(主成矿期)、热液早期阶段及石英-硫化物阶段。岩石及矿物的稀土元素特征表明:夕卡岩期的石榴石稀土元素配分模式呈折线形,具有明显的Eu正异常,显示岩浆热液成因特征,而主成矿期磁铁矿的稀土元素特征显示与石榴石具有同源性。热液期磁铁矿及黄铁矿具有明显的Eu负异常及弱的Ce负异常,表明富Eu成矿流体在夕卡岩期的高温氧化环境下形成了夕卡岩及铁矿体,在热液期则逐渐转变为低温还原环境后形成脉状和浸染状铁矿化及硫化物。成矿地质特征及岩石和矿物稀土元素特征指示红云滩铁矿床是岩浆热液成因的夕卡岩化的产物。Hongyuntan iron deposit in the eastern Tianshan of Xinjiang is hosted in volcanic- sedimentary series of the Lower Carboniferous Yamansu Formation. The ore bodies occur as layered, stratiform-like or lenticular, and are mainly controlled by NE- and NNE-trending compresso-shear thrust faults. The metallogenic periods including skarn, hydrothermal and supergene were recognized, and were further divided into four metallogenic stages including anhydrous skarn, degenerate alteration （principal metallogenic stage）, early hydrothermal and quartz-sulfide. Characteristics of REE of rock and mineral showed that chondrite-normalized REE pattern of garnet during the skarn period was polygonal line shape with obvious Eu positive anomaly, the genetic characteristic was magmatic hydrothermal, and the characteristic of REE of magnetite during the principal metallogenic stage was homogenous with that ofgarnet. Magnetite and pyrite during the hydrothermal period showed obvious Eu negative anomaly and weak Ce negative anomaly, so that Eu-rich ore-forming fluid developed skarn and iron ore body in the high temperature and oxidation environment during the skarn period, and gradually developed vein and disseminated iron mineralizer and sulfide in the low temperature and reduction environment during the hydrothermal period. Characteristics of metallogenic geology and REE of rock and mineral indicated that Hongyuntan iron deposit was the skarnized product with magmatic hydrothermal genesis.

关 键 词：磁铁矿 石榴石 夕卡岩 稀土元素 铁矿床 东天山 新疆 

分 类 号：P611.11[天文地球—矿床学] P618.31[天文地球—地质学]