关键词: 磁铁富矿, 成因, 成矿模式, 弓长岭

Abstract:

Based on the conclusion of the geological characteristics of Gongchangling iron deposit in Liaoning, this study analyzed the characteristics of major elements, trace elements and REE in magnetite quartzite and magnetiterich ore, and tested their composition of oxygen isotopes. The results show that: (1)the contents of Fe and SiO₂ in magnetiterich ore and magnetite quartzite are much different, while the contents of other elements are less. (2)The characteristics of trace elements in magnetiterich ore and magnetite quartzite are very similar to each other, the most types of REE distribution are also same, too. The main curves of REE distribution are a little bit rightinclined or just flat, and positive Eu anomaly which express the coherence and inheritability of these two ores. (3)The δ¹⁸O variation range of magnetite is -4.5‰ to 1.8‰ in magnetite quartzite, this range includes that of magnetiterich ore, which is similar to the geological occurrence of magnetiterich ore that occurrence in magnetite quartzite. It indicates that magnetiterich ore is formed by rebuilding the magnetic quartzite by hydrothermal water with negative δ¹⁸O. (4)Magnetiterich ore should be formed by metasomatism and desilicification  of hydrothermal metamorphic water(temperature at 500 ℃ or more and low values of δ18O, generally negative) with banded magnetite quartzite.

Key words: magnetite rich ore, genesis, mineralization model, Gongchangling