Deconstructing the Lomagundi-Jatuli Carbon Isotope Excursion
Deconstructing the Lomagundi-Jatuli Carbon Isotope Excursion
复制标题
DOI：
10.1146/annurev-earth-031621-071250
复制
发表时间：
2023-01
影响因子：
14.9
通讯作者：
M. Hodgskiss;P. Crockford;A. Turchyn
中科院分区：
文献类型：
--
作者：
M. Hodgskiss;P. Crockford;A. Turchyn
早-中古元古代lomagunti - jatuli偏移（LJE）是地球历史上观测到的最大震级（约+5 ~ +30‰）、持续时间最长（约1.3 ~ 2.5亿年）的碳酸盐岩正碳同位素偏移。LJE归因于大量的养分通量、生物圈规模的增加、全球碳循环的重组以及大气的氧化作用。然而，关于其成因、同步性、全球与局部范围以及在大气氧化中的作用，仍存在重大争议。在这里，我们回顾了现有的LJE模型和机制，并分析了~ 9400 δ13C和相关背景数据的汇编。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模型都必须考虑到缺乏明确定义的偏移起始和终止以及13c富集的相依赖表达。▪Lomagundi-Jatuli短途旅行（LJE）继续挑战目前对碳循环的理解。▪了解这一偏移对于通过地球历史重建生物地球化学循环和大气氧合作用至关重要。▪一些证据表明δ13CDIC的局部变化而非全球变化，并提出了异步局部漂移的可能性。▪确定LJE是全局同步的还是异步的对于区分不同的模型至关重要。《地球与行星科学年鉴》第51卷的最终在线出版日期预计为2023年5月。修订后的估计数请参阅http://www.annualreviews.org/page/journal/pubdates。
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 δ13C 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. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 51 is May 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.