摘要
锆石SHRIMP年龄测试结果表明,闽西南地区才溪岩体的形成年龄为150±3Ma。才溪二长花岗岩富硅、富碱,弱过铝。岩石富集LREE,具Eu负异常,*Eu值为0.54~0.66,亏损Ba、Nb、Ta、Sr、P、Eu、Ti。(87Sr/86Sr)i值较高,为0.710462~0.712265,εNd(t)为-8.68^-9.81,t2DM为1.51~1.61Ga。岩石中黑云母富铝、镁,在Fe2+-Fe3+-Mg2+三角图上落入壳幔混源区。根据岩体地质学、地球化学特征,结合岩石学和矿物学特征认为,才溪二长花岗岩是由中元古代地壳物质熔融形成的壳源型花岗岩,在岩浆形成过程中有少量幔源物质的加入,形成于由挤压向伸展过渡的构造环境。
Zircon SHRIMP results indicate that the Caixi pluton in southwest Fujian was formed at 150±3 Ma.Caixi monzonitic granite is characterized by rich Si and alkali,weakly peraluminous nature,negative Eu(^*Eu≈0.54-0.66)anomalies,enrichment of LREE,and depletion of Ba,Nb,Ta,Sr,P,Eu,Ti.They are characterized by Sr-Nd isotopic composition with(^878r/^86Sr)i being 0.710462-0.712265,εNd(t)-8.68--9.81 and t2Dm 1.51-1.61 Ca.The biotite of rocks is characterized by rich Al,Mg,and belongs to the type of crustmantle mixed sources based on the triangle diagram of Fe^2+-Fe^3+-Mg^2+.According to geochemical characteristics and petrological,mineralogical as well as geological data,it can be concluded that Caixi pluton belongs to the crust-source type granite formed by partial melting of the crust-derived rocks correlative to Proterozoic crust in the transformation from convergent to divergent tectonics.There were some materials mixed with the mantle materials in the process of rock formation.
作者
赵希林
毛建仁
陈荣
许乃政
曾庆涛
叶海敏
ZHAO Xi-lin;MAO Jian-ren;CHEN Rong;XU Nai-zheng;ZENG Qing-tao;YE Hai-min(Nanjing Institute of Geology and Mineral Resources,Nanjing 210016,China;Chinese Academy of Geological Sciences,Beijing 100037,China;Earth Science College,Jilin University,Changchun 130061,China)
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2007年第3期223-231,共9页
Acta Petrologica et Mineralogica
基金
中国地质调查局基础地质调查项目(1212010611805,300313000070)
关键词
才溪岩体
锆石SHRIMP年龄
地球化学特征
构造环境
闽西南
Caixi pluton
zircon SHRIMP age
geochemical characteristics
tectonic environment
southwestern Fujian Province
