Characteristics of Rare Earth Elements and Trace Elements in Hanwang Neo-Archaean Banded Iron Formations, Shandong Province
山东韩旺新太古代条带状铁矿的 稀土和微量元素特征

Hanwang banded iron formations (BIF) in Shandong Province constitute a large iron deposit of Anshan type formed in Neo-Archaean. In this paper, petrology and petrochemistry of Hanwang BIF were studied and a comparison was made with other BIF in the world. Petrological studies show that the BIF suffered greenschist facies to low amphibolite facies metamorphism and part of the magnetite was recrystallized whereas the other part of the magnetite preserved the characteristics of chemical sediments. In the diagram of TFe-(CaO+MgO)-SiO2, Hanwang BIF has a consistent distribution area with Wutaishan BIF and other BIF in the world. The REE contents of Hanwang BIF are low, showing characteristics of marine sediments in Archean. In the PAAS-normalized REE pattern, LREE are depleted and HREE are enriched relatively, with strong Eu positive anomaly, obvious Y positive anomaly and no visible Ce anomaly. These Hanwang BIF characteristics are itentical with characteristics of Gongchangling, Wu-taishan and many other Archean BIF in the world. As for trace elements, contents of Ti, V, Co, Ni, Mn, Sr and Ba are low. In trace elements distribution diagram normalized by primary mantle, U, Ta, La, Ce and P have positive anoma-lies, whereas things are just the opposite for K, Nb, Sr, Hf and Zr. The ratios of Sr/Ba, Ti/V and some other elements are also considered in this paper. A comprehensive study of Hanwang BIF shows that its ferruginous material was associated with volcanic hydrothermal solution and was formed in a marine chemical sedimentary environment.