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沉积岩中稀土元素曲线的一致性,可用来估算后太古代上部地壳的成分,这种成分近似于花岗闪长岩。大陆生长的岛弧模式可用来制定整个地壳成分,上部地壳是其中局部熔融而成,所剩余的部分便是下部地壳。太古代沉积岩的曲线图显示了当时上部地壳的不同成分。这些成分与推断的和太古代地壳成分相类似的现代岛弧型系列非常近似(除Cr、Ni含量较高之外)。因而,人们认为太古代地壳很少有分异作用,浅部花岗闪长岩更不发育。看来大陆演化是分幕的,而不是均匀地发展的。距今25亿年左右是产生分异上部地壳的一个重要时期,长期以来人们就把这个时间作为太古代和元古代的分界线。太古代地壳的厚度与现代地壳的厚度差不多。在太古代期问虽然产生了与现代岛弧型火山岩系列化学成分相似的火山岩,但似乎没有发生过传统的板块构造作用。没有表明原始硅铝壳广泛存在的证据,也没有证据说明存在一个与月球高地相似的斜长岩壳。在整个地质时代中,地球的半径没有经历多大的变化(>50公里)。
The consistency of the REE curves in sedimentary rocks can be used to estimate the composition of the Upper Permian crust, which is similar to granodiorite. The mainland-grown island arc pattern can be used to develop the entire crustal composition, where the upper crust is partially melted and the remaining portion is the lower crust. The Archean sedimentary rock diagram shows the different components of the upper crust at that time. These components are very similar to the series of modern island arcs inferred that are similar to the Archean crust (except for the higher levels of Cr and Ni). Thus, it is thought that the Archean crust has little differentiation and the shallow granodiorites are less developed. It seems that the evolution of the mainland is a sub-screen rather than a uniform development. About 2.5 billion years ago, it was an important period that produced the differentiation of the upper crust. For a long time, people took this time as the dividing line between the Archean and Proterozoic. The thickness of the Archean crust is about the same as the thickness of the modern crust. In the Archean Period, although similar volcanic rocks were found in the modern island arc volcanic series, it seems that no conventional plate tectonics has occurred. There is no evidence of the widespread existence of the original Si-Al shell and there is no evidence that there is an anorthosite shell similar to the lunar highlands. Throughout the geological age, the radius of the Earth has not undergone much change (> 50 km).