重庆高燕锰矿床成矿物质来源及沉积环境  

Ore-forming Material Source and Sedimentary Environment of Gaoyan Manganese Deposit in Chongqing

作　　者：贾伟 陈翠华[1] 张自贤 张燕[1] 宋志娇[1] 尹鑫 赖翔 辜鹰 JIA Wei;CHEN Cui-hua;ZHANG Zi-xian;ZHANG Yan;SONG Zhi-jiao;YIN Xin;LAI Xiang;GU Ying(School of Earth Sciences,Chengdu University of Technology,Chengdu 610059,China;205 Geological Team,Chongqing Bureau of Geology and Mineral Exploration,Chongqing 402160,China)

机构地区：[1]成都理工大学地球科学学院,成都610059 [2]重庆地质矿产勘查开发局205地质队,重庆402160

出　　处：《科学技术与工程》2020年第5期1724-1733,共10页Science Technology and Engineering

基　　金：国家自然科学基金(41372093);四川省科技厅项目(2018JY0477)。

摘　　要：在矿床地质研究基础上,通过对13件锰矿石样品进行系统的主量元素、稀土元素测试及分析,进一步探讨高燕锰矿床的成矿物质来源及沉积环境。结果表明:Mn/Fe平均值为17.34,P/Mn平均值为0.008,(CaO+MgO)/(SiO2-Al2O3)平均值为0.51,因此城口锰矿属于高磷低铁偏酸性锰矿石。Mn含量远高于TFe与MgO含量,可能是Fe^2+、Mg^2+易进入锰矿石的晶格占据Mn^2+的位置而形成完全类质同象的原因;Al和Ti含量相对较低,表明锰矿石沉积水体相对较深或距离陆源较远。高燕锰矿稀土元素总量不大,轻稀土明显较重稀土富集,δEu呈正异常,δCe呈弱的正异常。SiO2/Al2O3、Fe/Ti、(Fe+Mn)/Ti、Al/(Al+Fe+Mn)、La/Ce比值,以及SiO2-Al2O3、La-Ce、La/Yb-REE图解都显示出锰矿沉积过程中有大量热水(液)的注入,受陆源物质的影响程度较小,物源可能来自洋壳深部;锰矿与底板围岩稀土元素配分曲线相似,且锰矿层的产出严格受区域构造、地层、岩性的控制,反映了底板围岩可能为锰矿层的形成提供了部分物质来源;Sm/Nd比值指示锰矿层的沉积类型为壳层源沉积。Mn/Fe、ΣLREE/ΣHREE比值及δCe值,Ce、Eu异常,以及La N/Ce N-Al 2O 3/(Al 2O 3+Fe 2O 3)图解表明城口高燕锰矿床形成于大陆边缘向深海盆地过渡范围内即离岸较远、相对潮湿的深海或深水,还原、成矿温度大于250℃的沉积环境。Based on the geological study of the deposit,the ore-forming materials and sedimentary environment of the Gaoyan manganese deposit were further explored by testing and analyzing the main elements and rare earth elements of 13 manganese ore samples.Results show that the average value of Mn/Fe is 17.34,the average value of P/Mn is 0.008,and the average value of(CaO+MgO)/(SiO2-Al2O3)is 0.51.Therefore,Chengkou manganese ore belongs to high-phosphorus low-iron meta-acidic manganese ore.Mn content is much higher than TFe and MgO content,which may be the reason why Fe^2+and Mg^2+are easy to enter the lattice of manganese ore to occupy the position of Mn^2+and form complete homogeneity.The content of Al and Ti is relatively low,indicating that the sedimentary water body of manganese ore is relatively deep or far from the terrigenous source.The total amount of rare earth elements in Gaoyan manganese ore is not large and,the light rare earth is obviously richer than the heavv rare earth.Delta Eu is a positive anomaly and delta Ce is a weak positive anomaly.The ratios of SiO2/Al2O3,Fe/Ti,(Fe+Mn)/Ti,Al/(Al+Fe+Mn),La/Ce and the diagrams of SiO2-Al2O3,La-Ce,La/Yb-REE all show that.manganese ore injects a large amount of hot water(liquid)during the deposition process,which is weakly affected by terrigenous materials,and the source may come from deep oceanic crust.The REE distribution curve of manganese ore and that of floor rock are similar,and the output of manganese ore layer is strictly controlled by regional structure,stratum and lithology,reflecting that the floor rock may provide some material source for the formation of manganese ore.The Sm/Nd ratio indicates that the deposition type of the manganese ore layer is a shell source deposition.Mn/Fe,ΣLREE/ΣHREE ratio andδCe value,Ce and Eu anomalies,and La N/Ce N-Al 2O 3/(Al 2O 3+Fe 2O 3)diagrams indicate that the Chengkou Gaoyan manganese deposit is formed in the transition from the continental margin to the deep sea basin,that is,far away from the shore,relatively humid

关 键 词：地球化学 沉积环境 物质来源 高燕锰矿床 重庆城口 

分 类 号：P595[天文地球—地球化学]