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新疆磁海超大型铁矿区基性岩与铁成矿关系密切,是认识大规模铁成矿及其背景的关键.磁海铁矿区基性岩以辉绿岩为主,辉绿岩中断裂-裂隙控制板状铁矿脉群,单颗粒锆石U-Pb法测得206Pb/238U平均年龄为263.8±3.6Ma(n=11,MSWD=1.3),与二叠纪塔里木、东天山造山带、北山构造-成矿带等区域基性岩同时代.磁海铁矿区基性岩球粒陨石标准化微量元素蛛网图较平坦,Sr、Ba显示弱富集,Nb略亏损,球粒陨石标准化的REE配分曲线平坦,岩浆起源于亏损软流圈地幔,与其所在区域的北山构造-成矿带、东天山造山带、塔里木等地的基性岩均属碱性-钙碱性系列,它们的微量元素组成相近,岩浆性质相似,成生关系密切.磁海铁矿区基性岩可能是二叠纪地幔柱成因塔里木大火成岩省的组成部分,大规模铁成矿于地幔柱背景,北山构造-成矿带可能是塔里木地幔柱的一枝.
The close relationship between basic rocks and iron mineralization in the magnetotestauric iron ore area in the Xinjiang Uygur Autonomous Region is the key to understanding large-scale iron mineralization and its background.The basic rocks in the magnetic sea-iron ore area are mainly diabase, The average age of 206Pb / 238U measured by the single-particle zircon U-Pb method is 263.8 ± 3.6Ma (n = 11, MSWD = 1.3), which is consistent with the Permian Tarim and the East Tianshan Mountains Belt and Kitayama tectonic-metallogenic belt, etc. The normalized trace element cobweb maps of the mafic chondrule melanes in the magnetic-sea iron ore area are flat, while Sr and Ba show weak enrichment, while the Nb is slightly depleted. The chondrules The standardized REE distribution curve is flat. The magma originated from the depleted asthenosphere mantle, and is alkaline-calcareous series with the underlying rocks in the Beishan tectonic-metallogenic belt, the eastern Tianshan orogenic belt and the Tarim, With similar magmatic composition and close genetic relationship.The basic rocks of the magnetic sea iron ore may be part of the Permian mantle plume, a large igneous province, with large-scale iron mineralization on the background of mantle plume and Beishan Tectonic-metallogenic belt may be a branch of the Tarim plume.