The evolution of the continental lithosphere, unlike the oceanic one, lasts more than 3.5 Ga. This evolution was largely determined by thermal factors, such as the removal of heat from the Earth’s surface, the interaction of the conductive layer of the lithosphere with mantle thermal convection, and the strong dependence of the viscosity of the upper layers of the Earth on temperature. The aim of this work was to simulate the long-term interaction of these factors over a period of several Ga on the basis of the whole-mantle thermal convection equations. In our evolutionary model, the nucleus of continental lithosphere with a thickness of 50 kilometers was inserted in the mantle, which then began to grow in depth due to the reorganization of convection under the continental lid with a conductive heat transfer mechanism. For the self-consistent modeling of the lithosphere thickness changes in time we set the condition of viscosity jump by three orders of magnitude with a decrease in local temperature below 1200°C. The results of successive calculations demonstrated that the initial period of growth of the continental lithosphere due to its cooling, which takes about one Ga, is subsequently replaced by its slow thinning due to the accumulation of heat under a thick heat-insulating lithospheric cover. The calculated maximum of the average thickness of the growing lithosphere, estimated by temperature and viscosity, is 162 kilometers, however, when estimated by the conventional point of intersection of the lithospheric geotherms with mantle adiabat, it is 100 kilometers more. The increase in the average mantle temperature from the heat-insulating effect is about 100 K/Ga and continues both at the stage of the lithosphere thickening and at the subsequent stage of its slow thinning. The mantle warming up due to the presence of continents is one of the competing factors in the global process of the Earth’s secular cooling. The conclusion about the presence of two stages in the evolution of the continental lithosphere clarifies existing ideas about the formation of the current state of the outer layers of the Earth.

中文翻译：

---

大陆岩石圈热演化的两个阶段

与海洋岩石圈不同，大陆岩石圈的演化持续时间超过 3.5 Ga。这种演化在很大程度上是由热因素决定的，例如从地球表面带走热量、岩石圈传导层与地幔热的相互作用。对流，以及地球上层的粘度对温度的强烈依赖性。这项工作的目的是在整个地幔热对流方程的基础上模拟这些因素在几个 Ga 周期内的长期相互作用。在我们的演化模型中，厚度为 50 公里的大陆岩石圈核被插入地幔中，然后由于大陆盖下的对流重组，地幔开始向深处增长，具有传导传热机制。对于岩石圈厚度随时间变化的自洽建模，我们将局部温度降低到 1200°C 以下时粘度跃变的条件设置为三个数量级。连续计算的结果表明，大陆岩石圈由于冷却而生长的初始阶段大约需要 1 Ga，随后由于热量在厚厚的隔热岩石圈覆盖层下积累而缓慢变薄。根据温度和黏度估计，增长的岩石圈平均厚度的计算最大值为 162 公里，但按岩石圈地温与地幔绝热层的常规交点估计，则增加了 100 公里。隔热作用使平均地幔温度升高约 100 K/Ga，并在岩石圈增厚阶段和随后的缓慢减薄阶段持续增加。由于大陆的存在导致地幔变暖是地球长期冷却全球过程中的竞争因素之一。关于大陆岩石圈演化存在两个阶段的结论澄清了关于地球外层当前状态形成的现有观点。