Abstract The protracted tectonic and magmatic record of cratons over the Archaean Eon has been classically interpreted in terms of long-lived shallow-dipping subduction or repeated mantle plumes. In this paper, we use the 1D conductive heat equation to model the evolution of the geotherm of a generic felsic-dominated Archaean cratonic nuclei solely considering the secular decay of radioactive isotopes (238U, 235U, 232Th, and 40K), responsible for heat production in the crust. Using a range of plausible parameters for crustal thickness, lithospheric thickness, and surface heat flux, this modelling shows that Archaean crust was characterized by an initially high geothermal gradient at 3.5 Ga, with a Moho temperature close to 900 °C, and that it might have remained partially molten for about one billion years. The existence of a partially molten crust for an extended period of time offers an alternative option to shallow-dipping subduction or repeated mantle plumes for the understanding of the peculiar tectonic evolution of Archaean cratons marked by (i) protracted high-temperature metamorphism and magmatism associated with crustal differentiation, and (ii) widespread deformation characterized by structural domes attributed to the development of crustal-scale gravitational instabilities.

中文翻译：

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1 Ga上部分熔融太古代大陆地壳的长期冷却和结晶

摘要 太古宙上克拉通的长期构造和岩浆记录被经典地解释为长期浅倾俯冲或重复的地幔柱。在本文中，我们使用一维传导热方程来模拟一般长英质主导的太古代克拉通核的地热演化，仅考虑负责产热的放射性同位素（238U、235U、232Th 和 40K）的长期衰变在地壳中。使用一系列关于地壳厚度、岩石圈厚度和地表热通量的合理参数，该模型表明太古代地壳的特征是初始地温梯度为 3.5 Ga，莫霍面温度接近 900 °C，并且可能在大约 10 亿年的时间里一直处于部分熔融状态。