撞击加热和隐伏的冥古宙

作者：小柯机器人 发布时间：2026/6/28 23:34:40

近日，澳大利亚科廷大学Tim E. Johnson团队报道了撞击加热和隐伏的冥古宙。相关论文于2026年6月25日发表在《科学》杂志上。

冥古宙（≥40.3亿年前）期间地壳的性质尚不确定。早期地球动力学的数值模型强调地幔温度的控制作用，尽管有实证表明冥古宙存在强烈的撞击通量，但这些模型通常仅考虑内部产生的热量。

利用该撞击通量的随机模型，研究组表明撞击产生的累积热量在整个冥古宙期间将远远超过内部产生的热量。冥古宙的地壳在数千米深度以下将广泛熔融，导致致密的富铁镁物质发生重力分异，并驱动地壳平均组成趋向于更加富硅化。在全球范围内，撞击加热在39亿年后变得不再重要，地壳得以增厚。持久性大陆地壳大致出现在这一时期，很可能并非巧合。

附：英文原文

Title: Impact heating and the hidden Hadean

Author: Tim E. Johnson, Craig O’Neill, Simon Turner, Christopher L. Kirkland

Issue&Volume: 2026-06-25

Abstract: The nature of Earth’s crust during the Hadean eon [≥4.03 billion years ago (Ga)] is uncertain. Numerical models of early Earth geodynamics emphasize the control of mantle temperature but generally consider only internally derived heat, despite empirical evidence for an intense Hadean impact flux. Using a stochastic model of that flux, we show that the time-integrated heat due to impacts would have dwarfed that produced internally throughout the Hadean. Earth’s Hadean crust would have been extensively molten at depths below a few kilometers, causing gravitational segregation of dense, iron- and magnesium-rich material and driving average crustal compositions to become increasingly silica rich. Globally, impact heating would have become much less important after 3.9 Ga, allowing the crust to thicken. That enduring continental crust appeared around this time is likely not a coincidence.

DOI: aeb5402

Source: https://www.science.org/doi/10.1126/science.aeb5402