Deciphering the role—if any—that free oxygen levels played in controlling the timing and tempo of the radiation of complex life is one of the most fundamental questions in Earth and life sciences. Accurately reconstructing Earth's redox history is an essential part of tackling this question. Over the past few decades, there has been a proliferation of research employing geochemical redox proxies in an effort to tell the story of Earth's oxygenation. However, many of these studies, even those considering the same geochemical proxy systems, have led to conflicting interpretations of the timing and intensity of oxygenation events. There are two potential explanations for conflicting redox reconstructions: (i) that free oxygen levels were incredibly dynamic in both time and space or (ii) that collectively, as a community—including the authors of this article—we have frequently studied rocks affected by secondary weathering and alteration (particularly secondary oxidation) while neglecting to address the impact of this alteration on the generated data. There are now multiple case studies that have documented previously overlooked secondary alteration, resolving some of the conflicting constrains regarding redox evolution. Here, an analysis of a large shale geochemistry database reveals significant differences in cerium (Ce) anomalies, a common palaeoredox proxy, between outcrop and drill core samples. This inconsistency provides support for the idea that geochemical data from altered samples are frequently published in the peer-reviewed literature. As individuals and a geochemical community, most of us have been slow to appreciate how pervasive the problem is but there are examples of other communities that have faced and met the challenges raised by such quality control crises. Further evidence of the high potential for alteration of deep-time geochemical samples, and recognition of the manner in which this may lead to spurious results and palaeoenvironmental interpretations, indicate that sample archiving, in publicly accessible collections needs to become a prerequisite for publication of new palaeoredox data. Finally, the geochemical community need to think about ways to implement additional quality control measures to increase the fidelity of palaeoredox proxy work.

解读自由氧水平在控制复杂生命辐射的时间和节奏方面所起的作用（如果有的话）是地球和生命科学中最基本的问题之一。准确重建地球的氧化还原历史是解决这个问题的重要组成部分。在过去的几十年里，大量使用地球化学氧化还原代理的研究试图讲述地球氧化的故事。然而，这些研究中的许多研究，甚至那些考虑相同地球化学代理系统的研究，都导致了对氧化事件的时间和强度的相互矛盾的解释。对于相互矛盾的氧化还原重建有两种可能的解释：（i）游离氧水平在时间和空间上都具有令人难以置信的动态，或者（ii）总的来说，作为一个社区——包括本文的作者——我们经常研究受二次风化和蚀变（特别是二次氧化）影响的岩石，而忽略了这种蚀变对生成数据的影响。现在有多个案例研究记录了以前被忽视的二次改变，解决了一些关于氧化还原演化的冲突限制。在这里，对大型页岩地球化学数据库的分析揭示了露头和钻芯样品之间铈 (Ce) 异常（一种常见的古氧化还原代表）的显着差异。这种不一致为来自改变样本的地球化学数据经常发表在同行评审文献中的观点提供了支持。作为个人和地球化学社区，我们大多数人都没有意识到这个问题的普遍性，但也有其他社区面临并应对此类质量控制危机带来的挑战的例子。进一步证明深时地球化学样本改变的可能性很大，并认识到这可能导致虚假结果和古环境解释的方式，表明在可公开访问的收藏中存档样本需要成为发表新论文的先决条件。古氧化还原数据。最后，地球化学界需要考虑如何实施额外的质量控制措施，以提高古氧化还原代理工作的保真度。进一步证明深时地球化学样本改变的可能性很大，并认识到这可能导致虚假结果和古环境解释的方式，表明在可公开访问的收藏中存档样本需要成为发表新论文的先决条件。古氧化还原数据。最后，地球化学界需要考虑如何实施额外的质量控制措施，以提高古氧化还原代理工作的保真度。进一步证明深时地球化学样本改变的潜力很大，并认识到这可能导致虚假结果和古环境解释的方式，表明样本存档，在可公开访问的集合中需要成为发表新论文的先决条件。古氧化还原数据。最后，地球化学界需要考虑如何实施额外的质量控制措施，以提高古氧化还原代理工作的保真度。