华北克拉通南缘大纸房和嵖岈山花岗岩的锆石U-Pb定年、地球化学特征及成因启示  

Zircon U-Pb dating and geochemical features of the Dazhifang and Chayashan granites in the south margin of the North China Craton,and their implications for petrogenesis

作　　者：卢仁 梁涛 卢欣祥[5] Lu Ren;Liang Tao;Lu Xinxiang(Henan Academy of Geology,Zhengzhou 450016;Engineering Technology Center on Non-ferrous Metals Ore-prospecting of Henan Province,Zhengzhou 450016;Henan Key Laboratory of Metal Mineral Mineralization Geological Processes and Resource Utilization,Zhengzhou 450016;Key Laboratory of Deep Ore-prospecting technology Research for Non-ferrous Metals of Henan Province,Zhengzhou 450016;Institute of Natural Resources of Henan Province,Zhengzhou 450051)

机构地区：[1]河南省地质研究院,郑州450016 [2]河南省有色金属深部找矿工程技术研究中心,郑州450016 [3]河南省金属矿产成矿地质过程与资源利用重点实验室,郑州450016 [4]河南省有色金属深部找矿勘查技术研究重点实验室,郑州450016 [5]河南省国土资源科学研究院,郑州450051

出　　处：《地质科学》2023年第2期529-555,共27页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目(编号:U1504405);河南省有色金属地质矿产局首批科技创新专项资金项目(编号:KCXM202109);河南省科技计划项目(编号:162300410065);河南省国土资源厅科技攻关项目(编号:2016-08,2014-06)资助。

摘　　要：伏牛山余脉是华北克拉通南缘早白垩世花岗岩的集中出露区之一,其内花岗岩成因认识能为深入理解华北南缘燕山期岩浆活动规律和深部过程提供重要支撑。大纸房和嵖岈山岩株是伏牛山余脉花岗岩的典型代表,它们的U-Pb年龄分别为119.5±1.6 Ma和116.8±1.3 Ma,形成于早白垩世阿普特期。此外,它们的定年结果形成了锆石年龄谱,大纸房U-Pb年龄形成142 Ma和135 Ma两个峰值,嵖岈山U-Pb年龄形成135 Ma一个峰值。大纸房和嵖岈山花岗岩样品属高钾钙碱性系列,均具有富硅、碱和贫钙、镁的特征,分别属于弱过铝质和准铝质—弱过铝质花岗岩。大纸房和嵖岈山花岗岩样品均显示了Rb、Th、Zr、Hf的异常峰和Ba、Sr、P、Ti的异常谷。大纸房花岗岩样品的稀土总量介于176×10^(-6)~217×10^(-6)之间,(La/Yb)_(N)比值范围是43.0~55.5,它的稀土配分模式以轻稀土富集、重稀土亏损和负Eu异常不明显为特征。嵖岈山花岗岩样品的稀土总量介于230×10^(-6)~316×10^(-6)之间,(La/Yb)N比值范围是15.8~22.9,稀土配分模式具轻稀土富集、中稀土亏损和重稀土略微富集的“V”型(海鸥型)特征,负Eu异常明显。大纸房花岗岩高Sr和低Y、Yb,Sr/Y值为17.1~51.5,具有埃达克岩的特性,形成深度大于50 km,部分熔融源区残余相包括石榴子石、金红石和角闪石,且无(富钙)斜长石残留。嵖岈山花岗岩为低Sr、高Yb的南岭型(A型)花岗岩,其部分熔融源区残余相主要为角闪石和斜长石及金红石,无石榴子石残余,形成深度30 km以浅。大纸房和嵖岈山花岗岩形成于板内环境,经历了岩浆/流体体系混合再活化作用,是~120 Ma区域岩石圈拆沉作用的岩浆响应。The stretching branch of the Funiu Mountain is one of the Early Cretaceous granite areas in the southern margin of the North China Craton.The granite genesis can provide an important support for understanding of the Yanshanian magmatic activity and deep processes in the southern margin of North China.The Dazhifang and Chayashan granites are representative plutons in the stretching branch of the Funiu Mountain,and their U-Pb ages are 119.5±1.6 Ma and 116.8±1.3 Ma,which has suggested that they were formed in Aptian stage of the Early Cretaceous.The zircon age spectrums were formed with peak ages of~142 Ma and~135 Ma from the U-Pb ages of the Dazhifang granite and peak ages of~135 Ma from the Chayashan granite dating results.The samples of the Dazhifang and Chayashan granites were characterized by higher SiO2 and alkali,and lower MgO and CaO,and compositional spots fall into high-K calc-alkaline series.The Dazhifang and Chayashan granites belong to weakly peraluminous and metaluminous to weakly peraluminous serials,respectively.In the spider diagram,the peaks of Rb,Th,Zr and Hf,and troughs of Ba,Sr,P and Ti were shown for the Dazhifang and Chayashan granites.The total REEs of Dazhifang granite were from 176×10^(-6)to 217×10^(-6)with(La/Yb)N ratios of 43.0~55.5,and the characteristics of LREE-enrichment and HREE depletion without obvious Eu negative anomaly.The total REEs of the Chayashan granite were from 230×10^(-6)to 316×10^(-6)with(La/Yb)_(N)ratios of 15.8~2.9,and the characteristics of LREE-enrichment,MREE depletion and slightly enriched in HREE,showing a"V-shape"(seagull-shaped)REE pattern with strong Eu negative anomaly whoseδEu values were 0.35~0.40.The Dazhifang granite samples were high Sr and low Y and Yb contents with the Sr/Y ratios of 17.1~51.5 that was indicative of adakite affinity.The Dazhifang granite was originated from partial melting of the thickened lower crust with thickness>50 km,and its residual phases include garnet,rutile and amphibolite,and minor plagioclase.The Chayashan granite sa

关 键 词：大纸房 嵖岈山 埃达克岩 A型花岗岩 岩石圈拆沉 

分 类 号：P597.3[天文地球—地球化学] P612[天文地球—地质学]