【摘要】 宁芜盆地是长江中下游成矿带的7个矿集区之一,以中生代火山岩和玢岩铁矿的广泛发育为特征。凹山铁矿床位于盆地中部,是宁芜盆地玢岩型铁矿床的重要代表之一。本文首次利用成矿元素Fe的金属矿物对宁芜盆地凹山铁矿床的黄铁矿进行了Re-Os同位素测年,获得凹山铁矿床的黄铁矿Re-Os同位素等时线年龄为127.7±2.6Ma（n=5,MSWD=0.66）,直接代表凹山铁矿床的成矿年龄。¹⁸⁷Os/¹⁸⁸Os初始比值为1.73±0.56,γ_Os（t）值为527.18～535.93,介于地幔与地壳之间,结合已有研究成果,认为凹山铁矿床的成矿物质主要来源于富集地幔,少量来自地壳。更多还原

【Abstract】 Ningwu Basin,which is characterized by widespread porphyritic iron ore deposits,is one of the seven ore concentration areas in the Middle and Lower Yangtze metallogenic belt.The Washan iron deposit,which is one of the important representatives of porphyric iron-ore deposits in Ningwu Basin,is located in the middle of the basin.In this study,the result of Re-Os isotopic dating of pyrites collected from the Washan iron deposit was reported.It is for the first time that the metallogenic age was determined by iron-bearing metallic minerals in Ningwu area.The results show that the Re-Os isochron age of pyrites in Washan iron deposit is 127.7±2.6 Ma（n=5,MSWD=0.66）,which can directly represent the metallogenic age of the Washan iron deposit.The initial ¹⁸⁷Os/¹⁸⁸Os ratio is 1.73±0.56,and the γ_Os（t） values are from 527.18 to 535.93,which are between the value of the mantle and that of the crust.Combined with previous studies,it is suggested that ore-forming materials of the Washan iron deposit was mainly derived from the enriched mantle and partly from the crust.更多还原