摘要
为了解长安闪长岩岩体的形成与福州地区中生代岩浆活动的关系,对长安闪长岩岩体进行了岩相学和岩石地球化学特征研究,并与福州复式岩体进行了对比。发现长安闪长岩体呈岩株状分布于福州盆地西边缘,岩体的矿物组成主要为中性长石、角闪石、黑云母、石英,在岩体边缘具有少量的辉石。岩石地球化学特征为:(1)主量元素中SiO2为52.79%～58.89%,平均54.94%;碱度AR一般为1.4～1.9,平均为1.50,属钙碱性的范围;(2)微量元素具有富Rb、Ba、Th、U、K、Pb,而低Nb、Ta的特点;(3)稀土元素∑REE为119.327～169.148,平均143.273;LREE/HREE为8.550～11.672,平均9.435;δEu0.679～1.005,平均0.871,稀土分配模式为明显右倾典线,没有明显的Eu异常或仅具弱的负Eu异常。这些特征显示本区的闪长岩为中性偏基性部分的闪长岩,是福州复式岩体演化早期阶段的产物。
In order to understand the relationship between Changan diorite and the Mesozoic magmatism in the Fuzhou area, the petrography and petrogeochemistry of Changan diorite has been studied. The results show that the Changan diorite is located at the western edge of the Fuzhou basin and has the characteristics of general diorites. The minerals are made of neutral plagioclase, amphibole, biotite, quartz and a small amount of pyroxene at the edge of Changan diorite body. The value of SiO2 is between 52.79 ~ 58.89% with average 54.94%. The AR value is between 1.4 - 1.9% with average 1.5 which indicates that the diorite is belongs to the calc-alkaline series. The trace elements are rich in Rb, Ba, Th, U, K, Pb and low in Nb and Ta. The value of ∑YREE is between 1. 5119. 327 - 169. 148 with average 143. 273. The value of LREE/HREE is 8. 550 - ll. 67 and 9. 435 on average. The value of δEu is between 0. 679 - 1. 005 and 0. 871 on average implying that the fractionation of light rare-earth elements from high rare-earth elements is obvious. Negative Eu anomalies are few. The pattern of REE is a right incline line. These characteristics show that the Changan diorite is intrmediate or has a tendency to be basic in rock property, probably resulted from the early evolution of the Fuzhou complex massif.
出处
《地质与勘探》
CAS
CSCD
北大核心
2011年第6期1035-1043,共9页
Geology and Exploration
基金
福建省基金(2010J01257)
福州大学人才基金(826330)
国家大学生创新性实验计划联合资助
关键词
闪长岩
地球化学特征
复式岩体
福州盆地
Changan diorite
geochemical characteristics
complex massif
Fuzhou
作者简介
熊欣（1989年-），女，2010年毕业于福州大学，获资源勘查工程专业学士学位，现主要进行矿床学方面的科研工作。E-mail：499439314@qq.com
[通讯作者]王翠芝（1965年-），女，2007年毕业于中国地质大学（北京），获矿物学、岩石学、矿床学博士学位，高级工程师，现主要从事地学、矿业工程的教学和科研工作。E-mail：wcuizhi@163．com
