Mercury is gaining prominence as a proxy for large igneous province (LIP) volcanism in the sedimentary record. Despite temporal overlap between some mass extinctions and LIPs, the precise timing of magmatism relative to major ecological and environmental change is difficult to untangle, especially in marine settings. Changes in the relative contents of Hg in sedimentary rocks through time, or ‘Hg anomalies’, can help resolve the timing of LIP activity and marine extinctions. However, major questions remain unanswered about the fidelity of Hg as a proxy for LIP magmatism. In particular, depositional (e.g., redox) and post-depositional (e.g., oxidative weathering) processes can affect Hg preservation in marine sediments. These factors pose challenges for confidently using Hg as a fingerprint of volcanism. Here, we use the Hg anomaly at the Triassic–Jurassic boundary to explore the opportunities and challenges associated with two approaches that may help build a more robust interpretation of the Hg proxy: (1) measurements of sediments from diverse depositional environments, including lithologies with low Hg and organic carbon content, and (2) the simultaneous use of Hg stable isotope ratios. We present and compare Hg records from five geographically disparate Upper Triassic–Lower Jurassic marine sections that represent nearshore, mid-shelf, deep-water, and carbonate platform settings. These sedimentary sections span the emplacement of the Central Atlantic magmatic province (CAMP) and the associated end–Triassic extinction (ETE). Total organic carbon contents, carbonate contents, and Hg contents and stable isotope compositions demonstrate the multiple ways in which different depositional environments impact how Hg anomalies are expressed in ancient marine sedimentary rocks. Although we observe an increase in Hg/TOC during the ETE in each section, the pattern and duration of Hg enrichment differ notably between sections, and the timing is not always coincident with CAMP activity, illustrating how the depositional filter complicates the use of Hg/TOC ratios alone as a fingerprint of LIP magmatism. Importantly, Hg isotope measurements support a volcanic origin for the Hg anomalies during the ETE, suggesting CAMP was the Hg source during the extinction interval. These data support the use of Hg isotopes to help distinguish Hg loading that results from LIP magmatism on a global scale and emphasize the importance of making Hg proxy measurements from diverse depositional environments.

在沉积记录中，水星作为大型火成岩省 (LIP) 火山活动的代表而日益突出。尽管一些大规模灭绝和 LIP 之间在时间上重叠，但相对于主要生态和环境变化的岩浆活动的精确时间很难解开，尤其是在海洋环境中。沉积岩中汞的相对含量随时间的变化，或“汞异常”，可以帮助确定 LIP 活动和海洋灭绝的时间。然而，关于 Hg 作为 LIP 岩浆作用代表的真实性的主要问题仍未得到解答。特别是，沉积（例如氧化还原）和沉积后（例如氧化风化）过程会影响海洋沉积物中汞的保存。这些因素对自信地使用汞作为火山活动的指纹构成了挑战。这里，我们使用三叠纪-侏罗纪边界处的 Hg 异常来探索与两种方法相关的机遇和挑战，这两种方法可能有助于对 Hg 代理进行更可靠的解释：（1）测量来自不同沉积环境的沉积物，包括低 Hg 的岩性和有机碳含量，以及 (2) 同时使用 Hg 稳定同位素比率。我们展示并比较了来自五个地理上不同的上三叠统-下侏罗统海洋剖面的汞记录，这些剖面代表近岸、中陆架、深水和碳酸盐平台环境。这些沉积剖面跨越中大西洋岩浆区 (CAMP) 和相关的三叠纪末灭绝 (ETE) 的就位。总有机碳含量、碳酸盐含量、汞含量和稳定同位素组成表明，不同沉积环境以多种方式影响古代海相沉积岩中汞异常的表达方式。尽管我们在每个部分的 ETE 期间观察到 Hg/TOC 的增加，但 Hg 富集的模式和持续时间在不同部分之间显着不同，并且时间并不总是与 CAMP 活动一致，说明沉积过滤器如何使 Hg/TOC 的使用复杂化TOC 比率单独作为 LIP 岩浆活动的指纹。重要的是，汞同位素测量结果支持 ETE 期间汞异常的火山起源，表明 CAMP 是灭绝间隔期间的汞来源。