摘要
根据野外调查研究和145个样品的分析结果,讨论了浙西北中生代火山岩的基本特征,并在研究火山岩中微量元素组合、稀土元素分布和锶同位素组成的基础上得出如下结论:浙西北不同火山盆地和火山洼地中的酸性和中酸性火山岩的成岩机理基本相同,成岩物质主要来自硅铝壳,成岩温度为1020—1200℃。
The fundamental characteristics of Mesozoic volcanic rocks in the northwest of ZhejiangProvince are discussed on the basis of fieldwork and the data of analytical results of 145 samples. Basedon the study of REE distribution and strontium isotopic composition of the Mesozoic volcanic rocks, thewriters come to some conclusons as follows. The REE distribution patterns of volcanic rocks in differ-ent volcanic basins and depressions display some similarities, and belong to LREE type, though their ab-solute REE contents are different from each other. All these rock types yield rightward declined V-shaped curves with negative Eu anomalies. These acidic and intermediate acidity volcanic rocks haveinitial ^(87)Sr/^(86)Sr valus of about 0.7056 to 0.7139. All these indicate that the rock-forming materialscome from sialic crust. The rock-forming temperature is about 1020 to 1200°C.
关键词
中生代
火山岩
成岩
成因
Zhejiang
rare earth element
strontium isotope
volcanic rock
rock-forming mechanism
