The early to mid-Paleoproterozoic Lomagundi-Jatuli Excursion (LJE) is ostensibly the largest magnitude (approximately +5 to +30‰), longest duration (ca. 130–250 million years) positive carbon isotope excursion measured in carbonate rocks in Earth history. The LJE has been attributed to large nutrient fluxes, an increase in the size of the biosphere, a reorganization of the global carbon cycle, and oxygenation of the atmosphere. However, significant debate remains about its genesis, synchroneity, global-versus-local extent, and role in atmospheric oxygenation. Here we review existing models and mechanisms suggested for the LJE and analyze a compilation of ∼9,400 δ13Ccarb and associated contextual data. These data call into question the interpretation of the LJE as a globally synchronous carbon isotope excursion and suggest that any model for the LJE must account for both the absence of a clearly defined initiation and termination of the excursion and a facies-dependent expression of 13C-enrichment. ▪ The Lomagundi-Jatuli Excursion (LJE) continues to challenge current understandings of the carbon cycle. ▪ Understanding this excursion is critical for reconstructing biogeochemical cycles and atmospheric oxygenation through Earth history. ▪ Some evidence indicates local rather than global changes in δ13CDIC and raises the possibility of asynchronous, local excursions. ▪ Resolving whether the LJE was globally synchronous or asynchronous is essential for discriminating between different models.

中文翻译：

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解构洛马贡迪-贾图利碳同位素偏移

古元古代早期到中期的Lomagundi-Jatuli偏移（LJE）表面上是地球历史上在碳酸盐岩中测量到的最大震级（约+5至+30‰）、持续时间最长（约130-2.5亿年）的正碳同位素偏移。 LJE被归因于大量的养分通量、生物圈规模的扩大、全球碳循环的重组以及大气的氧化。然而，关于其起源、同步性、全球与局部范围以及在大气氧化中的作用仍然存在重大争议。在这里，我们回顾了为 LJE 建议的现有模型和机制，并分析了 ∼9,400 δ 的汇编13C碳水化合物以及相关的上下文数据。这些数据对 LJE 作为全球同步碳同位素偏移的解释提出了质疑，并表明任何 LJE 模型都必须考虑到偏移的明确定义的启动和终止的缺乏以及相依赖的表达13C-富集。 ▪ Lomagundi-Jatuli Excursion (LJE) 继续挑战当前对碳循环的理解。 ▪ 了解这一偏移对于重建地球历史中的生物地球化学循环和大气氧化至关重要。 ▪ 一些证据表明 δ 发生局部变化而不是全局变化13CDIC并提出了异步局部偏移的可能性。 ▪ 确定LJE 是全局同步还是异步对于区分不同模型至关重要。