福建沿海铝质A型花岗岩的地球化学及岩石成因  

Geochemistry and petrogenesis of aluminous A-type granitesin the coastal area of Fujian Province

作　　者：邱检生[1,2] 王德滋[3] 蟹泽聪史 BrentI A McInnes 

机构地区：[1]南京大学成矿作用国家重点实验室 [2]南京大学地球科学系,江苏南京210093 [3]南京大学地球科学系 [4]日本东北大学理学院矿物岩石矿床研究所 [5]CSIRODivisionofExplorationandMining

出　　处：《地球化学》2000年第4期313-321,共9页Geochimica

基　　金：国家自然科学基金资助项目!(49632080)

摘　　要：:以乌山、金刚山和新村三个典型岩体为例 ,系统研究了福建沿海铝质A型花岗岩的地质和地球化学特征。研究结果表明 ,铝质A型花岗岩常含有锰铝榴石、富锰白云母等特征的富铝矿物 ,化学成分上相对富铝 ,为一套准铝到弱过铝的岩石组合 ,并具有贫磷、贫钛 ,氧化指数较低等特征。与碱性花岗岩相比 ,其Nb、Ta、Zr、Hf、Ga、Y和Zn等元素的含量及稀土总量和Ga/Al比值均偏低 ,但轻、重稀土的分馏程度(尤其是重稀土的分馏程度)较高。两类岩石具有相似的稀土和微量元素分布模式 ,并具有相似的钕同位素组成 ,εNd (t)值分别变化于 -4 28～ -6 12和 -3 45～ -5 21之间 ,表明两者具有相似的岩浆源区 ,均为壳幔物质混熔的产物。根据对两类岩石矿物组合及地球化学特征的综合分析 ,推测岩浆体系中F。The geological and geochemical characteristics of aluminous A type granites in the coastal area of Fujian Province have been studied systematically by citing three rock masses of Wushan, Jingangshan and Xincun as typical examples. Investigation results have shown that the aluminous A type granites often contain aluminous rich minerals, such as spessartine and manganese rich muscovite, etc. Chemically, they are relatively rich in aluminum, and can be ascribed to a suite of metaluminous to weakly peraluminous rock association. They arealso poor in phosphorus and titanium, and have lower Fe2O3/(Fe2O3+FeO) ratios. Compared with the alkaline granites, aluminous A type granites have lower Nb, Ta, Zr, Hf, Ga, Y and Zn contents, ΣREE values and Ga/Al ratios, but higher LREE/HREE ratios, especially (Gd/Yb)N ratios, and display similar REE and trace element distribution patterns. The Nd isotope compositions of aluminous A type granites and alkaline granites are also similar, with εNd(t) values ranging from -4 28～-6 12 and -3 45～-5 21, respectively, which indicates that the source components of them are similar and both were originated from the partial meltingof crust mantle mixing materials. Based on a comprehensive analysis of the mineral associations and geochemical features of the two types of granites, it is conjectured that the different differentiation tendencies resulted from the variant F, Cl contents in magmas may be the main reason that cause the different geochemical characteristics of the two type granites.

关 键 词：铝质A型花岗岩 地球化学 岩石成因论 

分 类 号：P588.121[天文地球—岩石学]