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众所周知、金刚石来自金伯利岩、钾镁煌斑岩以及碱性和超镁铁质煌斑岩。文中指出,这些岩石与钙碱性煌斑岩一样,都高度富含金。煌斑岩中金的平均丰度至少要比“普通”火成岩高一个数量级,而许多个别的值甚至高出100—1000倍。金含量高可能反映出两个因素:(1)煌斑岩是从地球特别深的部位演变而来的——在这些部位不仅金刚石稳定,而且金也比其他火成岩源区更富集;(2)煌斑岩岩浆之所以能成为来自深部的金的适合载体是因为它们具有高的CO_2、H_2O、F、K、Rb和Ba含量,中等的S含量,而且所反映的流体实际上就是在地壳中沉积脉型金矿的流体。大多数类型的煌斑岩都与富集型地幔捕虏体一道从地球的深部迅速上升,因而能保留所有的金刚石和金。另一方面,钙碱性煌斑岩则经历了与地壳大规模的相互作用,从而使它们捕获了地壳捕虏体,同时失去了所有的金刚石和地幔捕虏体,其中至少还丢失了一些金;后者可解释它们常与中温热液金矿床伴生(例如太古代金矿床)的原因。
It is well known that diamonds come from kimberlite, potasitic lamprophyres, and alkaline and ultramafic lamprophytes. The article states that these rocks, like calc-alkaline lamprophytes, are highly gold-rich. The average abundance of gold in the lamprophyre is at least an order of magnitude higher than that of “normal” igneous rocks, while many individual values are even 100-1000 times higher. The high gold content may reflect two factors: (1) the lamprophyre evolved from a particularly deep part of the earth where not only diamond is stable, but also gold is more abundant than other igneous source areas; (2) ) Lampropite magma is a suitable carrier for gold from the deep due to their high CO 2, H 2 O, F, K, Rb and Ba contents and moderate S content, and the reflected fluid is actually in the crust In the sedimentary vein gold fluid. Most types of lamprophytes, together with enriched mantle xenoliths, rise rapidly from the depths of the earth and thus retain all diamond and gold. On the other hand, the calc-alkaline lamprophytes have undergone a large-scale interaction with the crust so that they capture the crustal xenoliths while losing all the diamond and mantle xenoliths, at least some gold ; The latter explain why they are often associated with mesothermal hydrothermal gold deposits (such as Archean gold deposits).