【摘要】 出露于华北克拉通南缘泌阳春水及其附近的黄山、祖师顶和角子山三个花岗岩体主要侵位于汝阳群和新元古代花岗岩中,本文采用锆石LA-ICPMS U-Pb定年方法,获得三个岩体的主体岩性黑云母二长花岗岩的岩浆锆石年龄分别为132.8±0.8Ma、131.9±1.1 Ma和120.9±0.8Ma,代表岩体的结晶年龄。三个岩体的岩性虽有差异,但主体岩性均为黑云母二长花岗岩,主要矿物为微斜条纹长石,暗色矿物为黑云母。三个岩体的地球化学特征均表现为高硅、高钾、贫Mg、贫Ca、高碱度率、高FeO^*/MgO比,和相对富集高场强元素Ta、Zr、Hf以及总体亏损不相容元素Ba、P、Sr、Ti和Nb等特征。SiO₂含量较高且变化范围较宽,K₂O/Na₂O比较高,主要属高钾钙碱性系列,A/CNK在1.023～1.094之间,属弱过铝质,MgO和CaO含量较低。微量（包括稀土）元素特征总体相似,∑REE含量总体较低,LREE相对HREE元素富集,具弱-中等负铕异常,（La/Yb）_N比9.32～42.43,Ga/Al（10⁴Ga/Al）比、Nb/Ta比、Rb/Nb比均与A型花岗岩的类似;t_2DM约为2.0Ga,ε_Nd（t）值在- 12.4～-13.5之间,与秦岭群负片麻岩的相似,(⁸⁷Sr/⁸⁶Sr)_i初始比值在0.70648～0.70823之间,表明物源来源于壳源。综合分析表明,三个岩体的花岗岩均为壳源铝质A2型（PA型）花岗岩,岩浆主要来源于早期俯冲进入华北克拉通南缘下部地壳中的北秦岭古老基底秦岭群负片麻岩的部分熔融以及分异作用,源岩熔融的热量主要由拆沉作用诱发的软流圈上涌物质的底侵作用提供。黄山、祖师顶和角子山三个花岗岩体形成于燕山期古太平洋板块对欧亚板块俯冲引起的岩石圈伸展环境。更多还原

【Abstract】 With the method of single zircon LA-ICP-MS U-Pb dating,the magmatic zircon ages of 132.8±0.8Ma,131.9±1.1 Ma and 120.9±0.8Ma are yield in the biotite-monzonitic granites from Huangshan pluton,Zushiding pluton and Juezishan pluton respectively,which are located around Chunshui,Biyang County,at the south margin of North China Craton and intruded Ruyang Group and the Neoproterozoic granite.The three piutons are all mostly biotite-monzonitic granite lithologically with limited variation, in which microperthite and biotite are conspicuous minerals.They are characterized by high silica,potassium,alkaline contents, FeO^*/MgO ratio and low magnesium and calcium,whereas rich in high field strength dements （HFSE）,such as Ta,Zr and Hf and lack in incompatible elements Ba,P,Sr,Ti,Nb et al.They have high SiO₂ contents with broad variation,low MgO and CaO contents,relatively high K₂O/Na₂O ratios,which indicates high-K calc-alkaline series,and of slight peraluminous.All of them have similar characteristics of trace elements （including REE） patterns by relatively low∑REE contents,moderate light rare earth elements （LREE）/ heavy rare earth elements （HREE） ratios and light to moderate negative Eu anomalies.The ratios of （La/Yb）_N （9.32～42.43）,Ga/Al,Nb/Ta and Rb/Nb are analogous to those of A-type granitoid.The t_2DM andε_Nd（t） values bear an analogy with those of paragneiss of Qinling Group,and they are about 2.0 Ga and vary between -12.4 and -13.5 respectively herein.The high initial ratios of ⁸⁷Sr/⁸⁶Sr （0.70648～0.70823） suggest continent crust involved in their source.Integrated analysis reveals that the three granitic plutons are A2-type （PA-type） granite of crustal origin.The magma was generated by partial melting of the aneient paragneiss of Qinling Group in North Qinling that have been subducted beneath the lower ernst of southern North China Craton and subsequent diffrentiation..Underplating of the upwelled asthenospheric material induced by delamination might have provided heat for the melting. The Huangshan pluton,Zushiding pluton and Juezishan granitoids were formed in the lithosphere extensional setting resulted from the subduction of the Paleo-Paeific Plate beneath the Eurasia Plate.更多还原