加州理工学院研究人员对一项重要的地质发现提出质疑。这个约20亿年前著名的碳同位素特征信号——称为Shunga-Francevillian事件——被认为是全球碳循环失衡的证据，但新研究表明这一解读可能存在偏差1。
研究团队通过分析俄罗斯Karelia地区Zaonega地层中的岩心样本，发现碳同位素异常并非源于全球性扰动，而是由局部岩浆、烃类和食甲烷微生物的共同作用产生1。具体而言，地层中存在显著的温度梯度：岩浆侵入体旁边约为350℃，向上300米处降至约72℃1。这种局部地质条件充分解释了观测到的碳同位素异常，而无需诉诸全球性的化学循环变化1。
Nivedita Thiagarajan为该研究的第一作者，成果已发表于《Geology》期刊1。这项发现对理解地球早期大氧化事件——即约20亿年前氧气开始在大气中积累这一重大化学转变——提出了新的思考1。研究团队计划进一步验证这一发现，通过GOE-DEEP项目分析来自加蓬Francevillian盆地的样本，相关钻探工作已于2025年夏季完成，预计由来自18个国家的国际研究团队于2026年进行取样1。
Researchers at the California Institute of Technology have challenged a long-standing interpretation of a prominent carbon isotope signature dating back approximately 2 billion years.1 The signal, known as the Shunga-Francevillian event, has been widely viewed as evidence of a global disruption in Earth's carbon cycle, but new analysis suggests this understanding may be incorrect.1
The team's investigation focused on rock core samples from the Zaonega formation in Karelia, Russia, and the Francevillian basin in Gabon.1 Rather than reflecting worldwide chemical imbalance, the carbon isotope anomaly appears to have been produced locally through the combined effects of magmatic intrusions, hydrocarbons, and methane-consuming microbes specific to the Zaonega basin.1 Researchers identified substantial temperature variations within the formation, measuring approximately 350 degrees Celsius adjacent to magmatic bodies and around 72 degrees Celsius at a distance of 300 meters above.1 These findings indicate that the carbon isotope irregularity was driven by localized depositional basin processes rather than global perturbations.1
The discovery raises questions about current understanding of the Great Oxidation Event, Earth's most significant chemical transformation when oxygen began accumulating in the atmosphere around 2 billion years ago.1 Led by first author Nivedita Thiagarajan, the research has been published in the journal Geology.1 A follow-up investigation through the GOE-DEEP project is planned to analyze Gabonese samples, with drilling completed in summer 2025 and international sampling by research teams from 18 nations scheduled for 2026.1
评论
还没有评论，欢迎留下第一条。