【摘要】 新疆和静县智博铁矿床位于西天山阿吾拉勒铁矿带东段,矿体呈层状、似层状、透镜状,赋存于下石炭统大哈拉军山组火山岩系中。矿床的成矿过程分为岩浆期和热液期两个成矿期,其中热液成矿期分为硅酸盐-氧化物阶段、硫化物阶段和石英-碳酸盐阶段。磁铁矿石和火山岩围岩稀土元素配分模式均为轻稀土相对富集的平缓右倾型,轻、重稀土元素之间分馏程度强,轻稀土元素及重稀土元素内部分馏程度均较弱,Eu负异常或异常不明显,无Ce异常。矿石和火山岩围岩微量元素配分曲线特征总体上基本一致,相对富集Rb、U等元素,亏损Ba、Ta、Nd、Ti等元素。磁铁矿δ18O值(3.7%~3.9%)与岩浆成因磁铁矿的δ18O值一致,δ32S值整体表现为幔源硫或岩浆硫特征。这些稀土、微量元素及同位素地球化学特征说明本区矿石和火山岩围岩具有同源性,成矿物质来源于大陆岛弧环境下的深源岩浆;该岩浆形成于准噶尔洋洋壳向南中天山-伊犁地块之下俯冲的岛弧环境中,岩浆在上侵过程中发生一定程度的地壳混染。结合矿床地质特征,认为智博铁矿的形成与岩浆活动有关,受矿浆贯入影响,后期热液作用对成矿有一定的贡献。更多还原

【Abstract】 Located in the eastern Awulale metallogenic belt of the western Tianshan Mountains,the Zhibo iron deposit is hosted in the volcanic rocks of the Lower Carboniferous Dahalajunshan Formation. The mineralization process of this deposit can be divided into magmatic and hydrothermal metallogenic periods. Of them,the hydrothermal metallogenic period includes three metallogenic stages: silicate-oxide,sulfide and quartz-carbonate stages. The volcanic rocks and iron ores have the similar distribution patterns of LREE enrichment as a relatively transitional right-dipping pattern with or no negative Eu anomalies and no Ce anomalies. There are some similarities between the volcanic rocks and iron ores in the trace earth element distribution patterns with Rb and U enrichment and depleted Ba,Ta,Nd,and Ti. The δ18O values( 3. 7% ~ 3. 9%) of magnetite are consistent with the δ18O value of magmatic magnetite; and the δ34S value shows a characteristic of mantle sulfur or magmatic sulfur. The analyses of trace,rare earth elements and isotopes of the volcanic rocks and iron ores show that volcanic rocks and magnetite have the same material source. The metallogenic material of the deposit derives from deep magma formed in an island-arc environment. The magma may formed in an island-arc environment where the Junggar oceanic crust was subducted beneath the Middle Tianshan-Yili crust,and the magma underwent contamination with continental crust during upwelling. Combined with the geological features of the deposit,we infer that the formation of Zhibo iron deposit was associated with the magmatism and related with ore pulp penetration,and the late hydrothermalism has some contribution to the mineralization.更多还原