新疆东天山小北矿铁矿地质、地球化学特征及成因

Geological,Geochemical Characteristics and Genesis of XiaoBeiKuang Iron Ore in East Tianshan Mountain,Xinjiang

小北矿铁矿位于新疆鄯善县西南部,阿奇克库都克断裂北侧。矿体受火山机构及火山岩相控制,矿石以致密块状构造为主,浸染状构造次之。金属矿物主要由磁铁矿、赤铁矿、黄铁矿、黄铜矿组成。岩体及接触带常见硅化、绿帘石化、矽卡岩化等。岩石地球化学特征表明,含矿岩性主要为中性-中酸性火山岩,里特曼指数σ为0.54~3.11,属低钾钙碱系列。Zr/Hf平均32.44,Nb/Ta平均16.27,与原始地幔平均值相似。δEu=0.08~0.21,平均0.13,Eu强烈亏损,δCe=0.83~0.97,平均0.91,表明Ce弱亏损。通过矿床地质和地球化学特征研究,初步认为小北矿铁矿属火山沉积-热液充填交代型铁矿。

XiaoBeiKuang iron ore is located in the southwest of shanshan county,Xinjiang,north of aqikekuduke fracture.Ore bodies are controlled by volcanic mechanism and volcanic rock facies, ore with dense block structure is givenpriority to disseminated structure.Metal minerals are mainly magnetite,hematite,limonite,pyrite and chalcopyrite.Rockcontact zone and common silicide,epidotization,skarnization.Petrogeochemical characteristics show that the ore-bearinglithology is mainly the neutral-intermediate-acid volcanic rocks,Rittmann index（σ） for 0.54~3.11, belongs to the low potassiumcalc-alkaline series.Averaged value of Zr/Hf is 32.44,Nb/Ta averaged 16.27,similar to the primitive mantle average.δEu=0.08~0.21,with an average of 0.13, Eu strongly losses, the δCe = 0.83~0.97,averaged 0.91,shows that Ce weaklosses.Based on the geological and geochemical research,preliminary thought the Xiaobeikuang iron ore belongs to volcanicsedimentary-hydrothermal filling metasomatic iron ore.