Four volcanically driven climatic perturbations led to enhanced continental weathering during the Late Triassic Carnian Pluvial Episode
Four volcanically driven climatic perturbations led to enhanced continental weathering during the Late Triassic Carnian Pluvial Episode
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DOI：
10.1016/j.epsl.2023.118517
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发表时间：
2024-01
影响因子：
5.3
通讯作者：
Peixin Zhang;Minfang Yang;Jing Lu;Zhongfeng Jiang;P. Vervoort;Kai Zhou;Xiaotao Xu;Huijuan Chen-Huijua
中科院分区：
文献类型：
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作者：
Peixin Zhang;Minfang Yang;Jing Lu;Zhongfeng Jiang;P. Vervoort;Kai Zhou;Xiaotao Xu;Huijuan Chen-Huijua
晚三叠世的干旱气候被一段特别潮湿的时期打断，这段时期被称为卡尼期（Carnian Pluvial Episode，CPE）。距今2.34 - 2.32亿年）。CPE通常与Wrangellia大火成岩省（LIP）的火山爆发有关，并被认为导致了全球变暖，风化作用增强，水脱氧和生物变化。然而，火山活动和化学风化之间的时间联系的直接证据尚未建立，由于整个CPE缺乏全面的记录。在这项研究中，地球化学和矿物学分析应用于一个湖相地层序列的济源盆地（中国北方），捕捉高分辨率的CPE。我们确定了四个不同的脉冲增强大陆化学风化的特点是提高化学指标的蚀变值和高岭石含量。大陆风化的这些峰值与Hg/TOC富集和负有机碳同位素偏移相吻合，这标志着四个短暂（约400 kyr）但强烈的Wrangellia LIP火山作用脉冲。结合湿度增加的迹象，我们的研究结果提供了直接和独立的证据，表明Wrangellia LIP喷发显着改变了CPE化学风化率，以应对全球变暖和湿润。在每次火山爆发后，该湖都经历了富营养化和水脱氧，但碳同位素的迅速恢复表明，该系统迅速恢复到火山扰动之前的状态。有机碳埋藏促进了广泛的dysopathy和缺氧沃茨，并通过增强风化CO2消耗可能发挥了关键作用，在快速气候恢复后，每次火山脉冲。
The arid climate of the Late Triassic was interrupted by a particularly humid episode known as the Carnian Pluvial Episode (CPE; ca. 234–232 million years ago). The CPE is often linked to eruptions in the Wrangellia Large Igneous Province (LIP), and is assumed to have led to global warming, enhanced weathering, water deoxygenation, and biotic changes. However, direct evidence for a temporal link between volcanic activity and chemical weathering has not yet been established due to the lack of comprehensive records across the CPE. In this study, geochemical and mineralogical analyses are applied to a lacustrine stratigraphic succession of the Jiyuan Basin (North China) that captures the CPE in high resolution. We identify four distinct pulses of enhanced continental chemical weathering characterized by elevated Chemical Index of Alteration values and kaolinite contents. These peaks in continental weathering coincide with Hg/TOC enrichments and negative organic carbon isotope excursions that mark four short (∼400 kyr) but intense pulses of Wrangellia LIP volcanism. In combination with signs of increased humidity, our findings provide direct and independent evidence that Wrangellia LIP eruptions significantly altered CPE chemical weathering rates in response to global warming and wetting. The lake experienced eutrophication and water deoxygenation after each volcanic pulse but the swift recovery of carbon isotopes suggests that the system rapidly returned to conditions prior to the volcanic perturbation. Organic carbon burial facilitated by widespread dysoxic and anoxic waters, and CO2consumption via enhanced weathering likely played crucial roles in the rapid climatic recovery after each volcanic pulse.