陕西勉县后沟-大坪山矿区磷、锰分层成矿地质地球化学特征

Geological and Geochemical Characteristics of P and Mn Layering Mineralization of Hougou-Dapingshan Area in Mianxian,Shaanxi Province

后沟-大坪山矿区位于南秦岭磷、锰成矿带的中东段,近年来在下寒武统塔南坡组中发现了3条含磷、锰矿化带,并圈定出多个锰矿体和磷矿体。磷、锰矿体具有多层性,常表现为磷、锰的分层成矿,多呈上锰下磷的空间分布特征。通过分析Ⅱ矿化带内地表和深部样品的常量元素、微量元素和稀土元素的地球化学特征,发现磷、锰矿其物质来源具有一定的相似性,但是磷、锰矿石沉积的氧化-还原条件、沉积区域以及沉积水体条件都存在差别,这可能是引起磷、锰分离单独成矿的主要原因。

Hougou-Dapingshan area,where three manganese（Mn）-phosphor（P） metallogenic belts were discovered recently in Lower Cambrain Tananpo Formation,located in the middle-eastern segment of the South Qinling Mn-P Metallogenic Zone.There were four Mn orebodies and one P orebody in the Ⅱ metallogenic belts.It is often that Mn-P orebodies were separated with a texture of upper Mn seam and lower P seam.The geochemical characteristics of the surface and deep rocks samples of major trace elements from the Ⅱmetallogenic belts were analyzed. The results show that the material source of Mn-P orebodies is similar, but both sedimentary environment including the sedimentary redox conditions, sedimentary area and water body condition is different. These are possible major reasons for P and Mn separate layering mineralization.