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首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Earth's continental crustal gold endowment
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Earth's continental crustal gold endowment

机译：地球的大陆地壳金end赋

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The analysis of the temporal distribution of gold deposits, combined with gold production data as well as reserve and resource estimates for different genetic types of gold deposit, revealed that the bulk of the gold known to be concentrated in ore bodies was added to the continental crust during a giant Mesoarchaean gold event at a time (3 Ga) when the mantle temperature reached a maximum and the dominant style of tectonic movement changed from vertical, plume-related to subhorizontal plate tectonic. A magmatic derivation of the first generation of crustal gold from a relatively hot mantle that was characterized by a high degree of partial melting is inferred from the gold chemistry, specifically high Os contents. While a large proportion of that gold is still present in only marginally modified palaeoplacer deposits of the Mesoarchaean Witwatersrand Basin in South Africa, accounting for about 40% of all known gold, the remainder has been recycled repeatedly on a lithospheric scale, predominantly by plate-tectonically induced magmatic and hydrothermal fluid circulation, to produce the current variety of gold deposit types. Post-Archaean juvenile gold addition to the continental crust has been limited, but a mantle contribution to some of the largest orogenic or intrusion-related gold deposits is indicated, notably for the Late Palaeozoic Tien Shan gold province. Magmatic fluids in active plate margins seem to be the most effective transport medium for gold mobilization, giving rise to a large proportion of volcanic-are related gold deposits. Due to their generally shallow crustal level of formation, they have a low preservation potential. In contrast, those gold deposits that form at greater depth are more widespread also in older rocks. This explains the high proportion of orogenic (including intrusion-related) gold (32%) amongst all known gold deposits. The overall proportion of gold concentrated in known ore bodies is only 7 x 10(-7) of the estimated total amount of gold available in the continental crust. This is less than the solubility of Au in common crustal fluids. A high potential for the existence of voluminous, hitherto undiscovered, gold resources may thus be inferred.
机译：通过对金矿的时间分布进行分析，并结合黄金生产数据以及不同遗传类型的金矿的储量和资源估算，发现已知集中在矿体中的大部分金都被添加到了陆壳中。在一次地幔温度达到最高且一次构造运动的主要方式从垂直羽状转变为水平下板块构造的同时（3 Ga），一次巨大的Mesoarchaean黄金事件中。从金化学，特别是高Os含量可以推断出第一代地壳金从相对热的地幔中的岩浆衍生，其特征是高度部分熔融。尽管其中的很大一部分金仍仅存在于南非Mesoarchaean Witwatersrand盆地的少量经过修饰的古浮游生物矿床中，约占所有已知金的40％，但其余部分已在岩石圈规模重复使用，主要是通过板块-构造诱发的岩浆和热液流体循环，以产生当前各种类型的金矿床。考古学家对陆壳后的幼金的添加进行了限制，但是表明了对某些最大的造山或与侵入有关的金矿的地幔贡献，特别是晚古生代的天山金矿。活跃板块边缘的岩浆流体似乎是动员金矿的最有效运输媒介，这导致了很大一部分与火山有关的金矿床。由于它们的地壳水平通常很浅，因此保存潜力低。相反，在更深的岩石中形成的深度更大的金矿床也更为广泛。这解释了在所有已知的金矿床中，造山（包括与入侵有关的）金的比例很高（占32％）。集中在已知矿体内的金的总比例仅为大陆壳中可用金的估计总量的7 x 10（-7）。这小于金在普通地壳流体中的溶解度。因此，可以推断出存在迄今尚未发现的大量黄金资源的巨大潜力。

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