辽宁本溪大台沟铁矿地球化学特征及其地质意义

GEOCHEMICAL CHARACTERISTICS AND GEOLOGICAL SIGNIFICATION OF THE DATAIGOU IRON DEPOSIT IN BENXI, LIAONING PROVINCE

通过主量元素和稀土元素相结合的方法,对大台沟铁矿成矿物质来源提出了有效制约.研究表明:大台沟铁矿化学成分主要由TFe2O3和Si O2组成,并且具有较低的Al2O3和Ti O2含量,这一特征与鞍本地区及山西五台山和冀东迁安地区铁矿一致,表明大台沟铁矿为火山沉积变质铁矿.稀土元素呈现轻稀土亏损、重稀土富集的特征,具有明显的Eu正异常特征,这些特征表明成矿物质来源于火山热液和海水的混合液.

Study on the major and rare earth elements （REE） of Dataigou iron deposit reveals that the average bulk compositions of the banded iron formations （BIF） are rich in TFe203 and SiO2 but low with A1203 and TiO2 contents. These characteristics are consistent with those of the iron deposits in Anshan-Benxi, Wutaishan and Qianan. It shows that the Dataigou deposit is of volcanic-sedimentary metamorphic iron deposit, characterized by depletion of light REE and enrichment of HREE, with distinct positive anomaly of Eu, which indicates that the BIFs are the products of chemical sedimentation from paleo-seawater with significant input of volcanic hydrothermal fluids.