Transatlantic exploration took place centuries before the crossing of Columbus. Physical evidence for early European presence in the Americas can be found in Newfoundland, Canada^1,2. However, it has thus far not been possible to determine when this activity took place^3,4,5. Here we provide evidence that the Vikings were present in Newfoundland in ad 1021. We overcome the imprecision of previous age estimates by making use of the cosmic-ray-induced upsurge in atmospheric radiocarbon concentrations in ad 993 (ref. ⁶). Our new date lays down a marker for European cognisance of the Americas, and represents the first known point at which humans encircled the globe. It also provides a definitive tie point for future research into the initial consequences of transatlantic activity, such as the transference of knowledge, and the potential exchange of genetic information, biota and pathologies^7,8.

跨大西洋探索发生在穿越哥伦布之前的几个世纪。在加拿大的纽芬兰可以找到早期欧洲存在于美洲的物理证据^1,2。但是，到目前为止，还无法确定该活动何时发生^3,4,5。在这里，我们提供了维京人在公元 1021 年出现在纽芬兰的证据。我们利用公元993 年宇宙射线引起的大气放射性碳浓度激增，克服了以前年龄估计的不精确性 （参考文献 ⁶）。我们的新日期为欧洲对美洲的认识奠定了一个标志，并代表了人类环绕地球的第一个已知点。它还为未来研究跨大西洋活动的初步后果提供了明确的联系点，例如知识的转移，以及遗传信息、生物群和病理学的潜在交流^7,8。