Korenaga Jun
Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06511, USA.
Life (Basel). 2021 Oct 26;11(11):1142. doi: 10.3390/life11111142.
The presence of exposed land on the early Earth is a prerequisite for a certain type of prebiotic chemical evolution in which the oscillating activity of water, driven by short-term, day-night, and seasonal cycles, facilitates the synthesis of proto-biopolymers. Exposed land is, however, not guaranteed to exist on the early Earth, which is likely to have been drastically different from the modern Earth. This mini-review attempts to provide an up-to-date account on the possibility of exposed land on the early Earth by integrating recent geological and geophysical findings. Owing to the competing effects of the growing ocean and continents in the Hadean, a substantial expanse of the Earth's surface (∼20% or more) could have been covered by exposed continents in the mid-Hadean. In contrast, exposed land may have been limited to isolated ocean islands in the late Hadean and early Archean. The importance of exposed land during the origins of life remains an open question.
早期地球上裸露陆地的存在是某种类型的前生物化学进化的先决条件，在这种进化过程中，由短期的昼夜和季节循环驱动的水的振荡活动促进了原始生物聚合物的合成。然而，早期地球上不一定存在裸露陆地，那时的地球很可能与现代地球大不相同。这篇小型综述试图通过整合近期的地质和地球物理研究结果，对早期地球上存在裸露陆地的可能性提供最新说明。由于冥古宙时期海洋和大陆增长的相互竞争效应，在冥古宙中期，地球表面相当大的一部分（约20%或更多）可能被裸露的大陆覆盖。相比之下，在冥古宙晚期和太古宙早期，裸露陆地可能仅限于孤立的海洋岛屿。裸露陆地在生命起源过程中的重要性仍然是一个悬而未决的问题。
