论文部分内容阅读
应用显微傅里叶变换红外光谱技术,对华北克拉通北缘汉诺坝地区的太古宙地体麻粒岩和新生代玄武岩中捕虏体麻粒岩(中生代底侵成因)的主要组成矿物(单斜辉石、斜方辉石、斜长石和石榴子石)进行了详细分析。结果表明,无论是地体麻粒岩还是捕虏体麻粒岩,岩石中的主要组成矿物均含有结构水,主要以OH形式存在。同种产状麻粒岩的矿物水含量(H2O%)均存在较大的变化,而且都远远超出实验误差,表明下地壳内水的分布可能是不均一的。两种产状麻粒岩的矿物结构水含量有着显著的不同,地体麻粒岩中矿物的水含量是捕虏体麻粒岩的2倍以上。太古宙—古元古代形成的安徽女山新生代玄武岩中的捕虏体麻粒岩具有与汉诺坝太古宙地体麻粒岩相似的水含量范围,但明显高于汉诺坝中生代形成的捕虏体麻粒岩。由此看来,早期(太古宙—古元古代)下地壳的水含量要比中生代形成的下地壳高得多,这可能指示不同时代下地壳在形成机制和性质上的不同。
The microscopic Fourier transform infrared spectroscopy (FTIR) was used to study the evolution of the magmatic rocks in the Archean granulite and Cenozoic basalts in the Hannuoba area, northern North China Craton. (Clinopyroxene, orthopyroxene, plagioclase and garnet) were analyzed in detail. The results show that the major minerals in the rocks are either structural water or both, mainly in the form of OH, both from the granulite and the xenolith. The mineral water content (H2O%) of the same producing granulite has great changes, and all far exceed the experimental error, indicating that the distribution of water in the lower crust may be uneven. The mineral content of the two producing granulites is significantly different. The water content of the granulite granulite is more than twice that of the xenolith granulite. Archean-Xenopus granulite in the Archean Cenozoic basalts formed in the Paleoproterozoic has a water content similar to that of the Archean granulite in Hannuoba, but significantly higher than the Mesozoic Xenolith granulite. In view of this, the water content of the early (Archean- Palaeoan) lower crust was much higher than that of the Mesozoic Lower Cretaceous, which may indicate the different mechanisms and properties of the crust under different ages.