鲁西徂徕山南部花岗闪长斑岩地球化学特征及构造意义  

Geochemical characteristics and tectonic significance of granodioritic porphyry in southern Culaishan of western Shandong Province

作　　者：刘伟 靳立杰 阎海青 王刚 江振国 杨帆 LIU Wei;JIN Lijie;YAN Haiqing;WANG Gang;JIANG Zhenguo;YANG Fan(No.1 Institute of Geology and Mineral Resources of Shandong Province,Jinan 250014,China;Shandong Engineering Laboratory for High-Grade Fe Ores Exploration and Exploitation,Jinan 250014,China;Shandong Testing Center of China Metallurgical Geology Bureau,Jinan 250013,China)

机构地区：[1]山东省第一地质矿产勘查院,山东济南250014 [2]山东省富铁矿勘查技术开发工程实验室,山东济南250014 [3]中国冶金地质总局山东局测试中心,山东济南250013

出　　处：《山东理工大学学报（自然科学版）》2024年第4期14-19,共6页Journal of Shandong University of Technology:Natural Science Edition

基　　金：山东省自然资源厅基金项目(SDZS-2015-GTT01)。

摘　　要：为限定鲁西地区中生代侵入岩岩浆来源及岩石圈减薄时间,提供地球动力学背景数据,本文结合已发表的U-Pb年代学,通过对鲁西徂徕山南部中生代花岗闪长斑岩开展岩相学及岩石地球化学研究,讨论了岩石成因、源区性质及形成的构造环境。结果表明:岩石具有高硅、富碱富铝的特征,轻稀土元素富集,重稀土元素亏损,富集Rb、Ba、Sr等大离子亲石元素,亏损Nb、P、Ti等高场强元素,弱Eu负异常,属于弱过铝质高钾钙碱性系列“S”型花岗岩,是新太古代晚期华北克拉通古老地壳部分熔融形成的产物;花岗闪长斑岩锆石LA-ICP-MS U-Pb年龄为127±1.2 Ma,结合区域构造演化背景,认为鲁西徂徕山南部花岗闪长斑岩形成于古太平洋板块向欧亚大陆俯冲背景下的伸展环境,是早白垩世时期华北克拉通岩石圈减薄和克拉通破坏作用在鲁西徂徕山地区的地质响应。In order to constrain the magmatic source of Mesozoic intrusive rocks and lithosphere thinning time in western Shandong Province and provide geodynamic background data,the petrographic and geochemical study of Mesozoic granodioritic porphyry in southern Culaishan area of western Shandong Province was carried out based on the published U-Pb chronology.The genesis,nature of source area and tectonic environment of the rock were discussed.The results showed that the porphyry has high silicon,alkali and aluminum content,enrichment in light rare earth elements and large ion lithophile elements such as Rb,Ba and Sr,depletion in heavy rare earth and high field strength elements such as Nb,P and Ti,and a weak Eu negative anomaly.It belongs to weak peraluminous high potassium calc-alkaline series S-type granite,originates from the partial melting of the ancient crust of North China Craton in the late Neoarchean.The zircon LA-ICP-MS U-Pb age of granodioritic porphyry was 127±1.2 Ma.Combined with regional tectonic evolution background,the granodioritic porphyry was inferred to be formed in the extensional environment of paleo-Pacific plate subduction to Eurasia continent,and was a geological response to the lithosphere thinning and destruction of North China Craton during the Early Cretaceous in the Culai Mountains area of western Shandong Province.

关 键 词：稀土元素 地球化学 花岗闪长斑岩 徂徕山 

分 类 号：P588.1[天文地球—岩石学] P597[天文地球—地质学]