豫西熊耳山斑竹寺岩体的地球化学特征及地质意义

Geochemical features and geologic implcations of Banzhusi cranite porphyry body in Xiong'er Mountain, western Henan Province

豫西熊耳山已知的121个内生金属矿床（点）均位于经线112°E以西，其东尚未发现内生金属床（点），对位于经线112°E以东燕山期斑竹寺花岗斑岩开展成因研究有助于区域找矿思路的转变。斑竹寺岩体具有高硅、富碱高钾、贫镁低钙的特征，属于高钾钙碱性系列，AVCNK值介于1．02～1．09之间。它的稀土配分模式具有右倾平滑、轻稀土富集、重稀土亏损的特征，（LaMb）w范围为18．48-24．85，无明显Eu异常，微量元素蛛网图中Rb和Th富集，具有明显的Nb、Ta、P和Ti负异常。斑竹寺岩体的Sr含量高、Y及Yb含量低，具有埃达克岩属性，它是加厚大陆下地壳的部分熔融形成的，部分熔融源区残余相矿物包括石榴石和金红石。斑竹寺岩体是早自垩世区域岩石圈拆沉作用的产物，区域上广泛产出与其形成时代相近的成矿作用，它还显示了Au、Db、Zn等成矿元素的异常富集特征，斑竹寺岩体深部及周缘具有较大成矿潜力。

There are 121 endogenetic metal deposits and mineralizaion spots distributed in west of longitude 112° E in Xiong＇ er Mountain, western Henan Province. The endogenetic mineralization, however, was not found in east of longitude 112°E in Xiong＇ er Mountain. It is the petrogenesis of Yanshanian Banzhusi body in east of longitude 112°E in Xiong＇ er Mountain that becomes useful to change prospecting ideals in this area. Banzhusi body is characterized by higher in SiO2 and alkali enriched in K20, lower in MgO and CaO. Compositional spots of Banzhusi body fell into high-K calc-alkaline series in w（SiO2）- w（K2O） diagram. A/CNK ratios of Banzhusi body are from 1.02 to 1.09. In chondrite-normalized REE patter diagram, Banzhusi body samples have shown the characteristics of LREE-enriched, and HREE depleted without obvious Eu anomaly. The （La/Yb）N ratios of Banzhusi body are from 18.48 to 24.85. In spider diagram, the enrichment of Rb, Th, and depletion ofNb, Ta, P and Ti are displayed. Samples of Banzhusi body are higher in Sr, and lower in Y and Yb, which indicated Banzhusi body is Adakite. Banzhusi body is originated from partial melting of the thickened lower crust, and its residual phases of partial melting source include garnets and rutiles. Banzhusi body is products of regional lithosphere delamination in early Cretaceous, and the formation age of Banzhusi body is close to the time of regional endogenetic mineralization. The obvious enrichment in Au, Pb and Zn have been found in Banzhusi body. It was considered that Banzhusi area have large mineralization potential.