嵩山地区海神庙岩体地球化学特征及其地质意义

Geological significance and geochemistry characteristics of Haishenmiao pluton in the Songshan area

通过1∶5万数字填图从原登封杂岩新解体出新太古代海神庙花岗岩体,岩体呈灰白色,中细粒花岗结构,片麻状构造,条带状构造。岩相学特征和主量元素表明其属于TTG岩系,岩石具有高硅（〉68%）、低铝（平均为13.61%〈15%）、富碱（Na2O质量分数3.42%-5.63%）、贫钙镁的特征,δ值为1.14-2.13,显示其钙碱性特征。∑REE偏低,轻重稀土强烈分异,重稀土强烈亏损,Eu出现微弱异常。在初始地幔标准化图解中具有一致明显的Th、K、La、Pb、Nd、Sm正异常以及U、Ta、Nb、P及Ti负异常,高场强元素Zr-Hf轻微负异常或无异常。Sr含量和Sr/Y比值较高,Cr、N、Yb、Y含量较低,与新生代高硅埃达克岩地球化学特征相似,岩石的Nb、Y、Rb、Th、La和Yb之间的关系特征与岛弧火山岩相似。

Haishenmiao granitic pluton is disintegrated from Dengfeng complex rock by 1 I 50000 digital geologicalmapping. Original and tectonic environment are studied by using its petrologic feature, petro-graphicfeatures, and geochemical characteristics. The petrography and major elements indicate that Haishenmiao graniticpluton belongs to TTG gneisses, the concentration of Si02 is greater than 68% , the concentration of Na20is 3 .42% -5 . 63 % , and the concentration of Al2O3 is average 13 . 61 % 〈15% , poor in content of Ca, Mg.The value of δ is 1. 14 -2. 13. Haishenmiao granitic pluton has low ∑REE, with differentiated LREE/HREEpatterns. In the initial standardization diagram of the mantle, it has the similar geochemical characteristics ofthe high Si Cenozoic adakite with high content of S r , high ratio of Sr/Y, low content of Cr, N , Yb,Y , andit also has the similar relational features among Nb, Y ,Rb,Th, La and Yb in the rocks with island arc volcanics.