及其地質(zhì)意義
(1．中南大學 有色金屬成礦預測教育部重點實驗室，長沙 410083；
2．中南大學 地球科學與信息物理學院，長沙 410083；
3．中國五礦邯邢礦業(yè)邯鄲地質(zhì)勘查設(shè)計有限公司，邯鄲 056000)
摘 要: 為了解河北武安礦山村礦田兩類不同就位環(huán)境下的鐵成礦差異，對兩類鐵礦進行了稀土元素地球化學研究；一類為就位于巖體外部接觸帶的玉石洼型鐵礦，另一類為產(chǎn)于巖體內(nèi)部的五家子型鐵礦。前者2件致密塊狀鐵礦樣品的∑w(REE)含量變化范圍為10.195×10−6~11.615×10−6，w(LREE)/w(HREE)比值為11.639~13.160，δ(Eu)為0.844~0.957；后者3件脈狀鐵礦石樣品∑w(REE)含量變化范圍為44.412×10−6~49.840×10−6，w(LREE)/w(HREE)比值為4.387~5.724，δ(Eu)為0.306~0.438。上述5件鐵礦樣品稀土元素分配型式均為銪異常不明顯的右傾曲線，與4件巖體樣品稀土特征基本相似，成礦流體與巖漿流體關(guān)系密切。五家子磁鐵礦稀土總量∑w(REE)較高，具明顯銪負異常，輕、重稀土分餾程度低，與典型矽卡巖就位環(huán)境下的玉石洼鐵礦區(qū)別明顯。結(jié)合礦體產(chǎn)出的野外地質(zhì)特征，推測除矽卡巖成礦機制外，礦山村礦田內(nèi)鐵礦存在與巖漿關(guān)系更密切的成礦機制。
關(guān)鍵字: 礦山村礦田；鐵礦；地球化學；稀土元素；成礦流體；矽卡巖
geological significance of iron deposit in Kuangshancun ore field of
Wu’an County, Hebei Province, China
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
3. Hanxing Mining Geological Exploration Design Co., Ltd., China Minmetals Coporation, Handan 056000, China）
Abstract:In order to clarify metallogenic differences of iron deposit in different locational environments, the contents of rare earth elements of two types of iron ore and wall rock in ore field of Wu’an County, Hebei Province, China, were analyzed. One is two massive iron ore samples which are from the exterior contact zones of Yushiwa ore deposit (∑w(REE)=10.195×10−6−11.615×10−6, w(LREE)/w(HREE)=11.639−13.160, δ(Eu)=0.844−0.957). The other is three veinlet iron ore samples inside of Wujiazi ore deposit which are in the form of xenolith (∑w(REE)=44.412×10−6− 49.840×10−6, w(LREE)/w(HREE)=4.387−5.724, δ(Eu)=0.306−0.438). The REE distribution of the five samples is right deviation, with slightly negative Eu anomalies, and similar with that of the four rock samples, which show that the origin of ore-forming fluids is closely related with magmatic fluids. In contrast, the total contents of rare earth elements of Wujiazi are high with negative Eu anomalies, and the fractionation of LREE and HREE is weak. Combined with field geological operations, it is speculated that Kuangshancun ore field has certain kinds of ore-forming mechanism closely related with magma expect for skarns ore-forming mechanism.
Key words: Kuangshancun ore field; iron deposit; geochemistry; rare earth elements (REE); metallogenic fluid; skarn
