东秦岭鱼池正长岩体岩石地球化学特征及稀有金属元素、稀土元素矿化  

Geochemical Charateristics of Yuchi Syenites from East Qinling and the Rare Metal Elements,Rare Earth Element Mineralization

作　　者：吴成斌[1] 侯广顺[1,2] 向世红 齐永安[1] 支风岐 王明国 

机构地区：[1]河南理工大学资源环境学院,河南焦作454003 [2]河南省有色金属地质勘查总院,郑州450052

出　　处：《地质科技情报》2017年第2期58-64,共7页Geological Science and Technology Information

基　　金：国家自然科学基金项目(41003015);河南省博士后基金项目"河南鹤壁地区金刚石成矿潜力地质条件研究"

摘　　要：河南方城鱼池正长岩体属于东秦岭北部富碱侵入岩,为本区出露规模最大的碱性岩体,迄今研究较为薄弱。通过对鱼池正长岩体的主量、稀土和微量元素岩石地球化学成分的系统分析和综合研究,探讨了该岩体岩浆源区特征、构造环境和该地区正长岩体稀有金属、稀土元素含矿性。鱼池正长岩体w(SiO2)为57.35%~61.38%,富碱,高Al,贫Ca、Mg和Ti,A/CNK为0.95~1.07,属于过铝质碱性岩。岩石稀土元素总量较高,(La/Yb)N比值为25.86~35.48,强烈富集轻稀土元素,轻、重稀土元素分馏明显,δEu值为0.48~0.63,具中等负Eu异常。富集大离子亲石元素、相对亏损高场强元素。由此表明:鱼池正长岩体的岩浆物质主要来源于地幔,后经过大量的壳源物质的混染,且岩体形成于板内拉张环境。另外该地区正长岩体w(ZrO2)为0.039%~0.174%,LREEO质量分数为0.026%~0.15%,显示了良好的Zr和LREE等稀有金属元素、稀土元素的矿化信息,具有巨大的成矿潜力。Yuchi syenites, in Fangcheng County, Henan Province, belong to the alkali rocks zone in north- ern part of East Qinling orogenic belt, and are the biggest outcrop stock in the belt. This paper presents the major and trace element characteristics of Yuchi syenites, and discusses its magma source, tectonic en- vironment and the relationship with rare metal elements and rare earth element mineralization. The SiO2 content of Yuchi syenites is 57.35% --61.38%, with enriched alkaline, high Al,and depleted in Ca, Mg and Ti , and hence, belongs to peraluminous alkaline. The rocks have high rare earth elements （REEs） content, and are highly enriched in light rare element, and the light REE. The heavy REE differentiation is obviously high, with LaN/YbN ratio between 25.86--35.48, δEu between 0. 48--0. 63, middle negative Eu anomaly. The rocks are enriched in LILE and are depleted in HFSE. This research shows that Yuchi syenitesrs magma source is derived from mantle, and is extensively assimilated by the continental crust. Yuchi syenites were formed within plate extension environment. The ZrO2 content of Yuchi syenites is 0. 039%--0. 174% and LREEO content is 0. 026%--0.15%. This indicates good Zr and LREE mineraliza- tion and metallogenic potential.

关 键 词：东秦岭 鱼池正长岩体 稀有金属 稀土元素 成矿潜力 

分 类 号：P595[天文地球—地球化学]