Abstract Until recently, the known impact record of the early Solar System lay exclusively on the surfaces of the Moon, Mars, and other bodies where it has not been erased by later weathering, erosion, impact gardening, and/or tectonism. Study of the cratered surfaces of these bodies led to the concept of the Late Heavy Bombardment (LHB), an interval from about 4.1 to 3.8 billion years ago (Ga) during which the surfaces of the planets and moons in the inner Solar System were subject to unusually high rates of bombardment followed by a decline to present low impact rates by about 3.5 Ga. Over the past 30 years, however, it has become apparent that there is a terrestrial record of large impacts from at least 3.47 to 3.22 Ga and from 2.63 to 2.49 Ga. The present paper explores the earlier of these impact records, providing details about the nature of the 8 known ejecta layers that constitute the evidence for large terrestrial impacts during the earlier of these intervals, the inferred size of the impactors, and the potential effects of these impacts on crustal development and life. The existence of this record implies that LHB did not end abruptly at 3.8–3.7 Ga but rather that high impact rates, either continuous or as impact clusters, persisted until at least the close of the Archean at 2.5 Ga. It implies that the shift from external, impact-related controls on the long-term development of the surface system on the Earth to more internal, geodynamic controls may have occurred much later in geologic history than has been supposed previously.

中文翻译：

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晚期重轰炸的地面记录

摘要 直到最近，已知的早期太阳系撞击记录都只存在于月球、火星和其他天体的表面，在这些天体上，它没有被后来的风化、侵蚀、撞击园艺和/或构造作用抹去。对这些天体的陨石坑表面的研究导致了晚期重轰击 (LHB) 的概念，这是大约 4.1 至 38 亿年前 (Ga) 的间隔，在此期间内太阳系中的行星和卫星的表面受到影响到异常高的轰击率，然后下降到大约 3.5 Ga 的低撞击率。然而，在过去 30 年中，很明显，有至少 3.47 至 3.22 Ga 的大撞击的地面记录以及从2.63 到 2.49 Ga。 本文探讨了这些影响记录中较早的记录，提供关于 8 个已知喷出物层的性质的详细信息，这些层构成了这些间隔中较早时期的大型地球撞击证据，推断撞击物的大小，以及这些撞击对地壳发育和生命的潜在影响。这条记录的存在意味着 LHB 并没有在 3.8-3.7 Ga 突然结束，而是持续的或作为撞击群的高撞击率至少持续到太古代在 2.5 Ga 结束时。这意味着从对地球表面系统长期发展的外部、与撞击相关的控制到更内部的地球动力学控制可能发生在地质历史中比以前假设的要晚得多。