【摘要】 A型花岗岩的研究由来已久,其最早指的是碱性、无水、非造山的花岗岩。由于分析角度的不同,其在地球化学特征上与I、S型花岗岩存在重叠和过渡现象,从而造成地球化学判别图解的多解性。构造环境分析发现研究区内燕山期花岗岩体形成于碰撞期向造山期后发展的转折时期,构造应力场由挤压环境向伸展环境转换。通过锆石饱和温度计算反演出岩浆熔融温度在731℃～780℃,低于铝质A型花岗岩的平均结晶温度800℃。文章阐述在研究A型花岗岩时应严格从其"3A"的原始定义出发,避免对A型花岗岩的"扩大化"。更多还原

【Abstract】 A-type granite has been studied for a long time.It was originally referred to as alkaline,anhydrous,non-orogenic granite.Due to the different analysis angles,it has overlapping and transitional phenomena with the I and S-type granites in geochemical characteristics,which leads to the multi-solution of geochemical discrimination diagrams.The tectonic environment analysis found that the Yanshanian granite body in the study area was formed in a transition period from the collision period to the post-orogenic period,and the tectonic stress field was transformed from the extrusion environment to the extension environment.The inversion magmatic melting temperature is calculated from the zircon saturation temperature at 731℃～780℃,which is lower than the average crystallization temperature of the aluminum A-type granite at 800℃.The author believes that the study of A-type granite should strictly follow the original definition of "3 A" to avoid "magnification" of A-type granite.更多还原