The first major mass extinction of trilobites occurred at the transition from Cambrian Series 2 (CS₂) to Miaolingian (M) and coincided with a large marine transgression and volcanic eruptions of a large igneous province (LIP). Understanding the causal links between these events is important in deciphering environmental changes and life evolution at that time. This paper presents S-Hg-C isotopic and Fe speciation data for calcareous shales from the CS₂-M Yangliugang Formation in the Dongjin section, South China. In the lower part of this section (Interval I), calcareous shales have limited S isotopic differences between carbonate-associated sulfates (${\delta }^{34}$S_CAS) and pyrites (${\delta }^{34}$S_Py) with ${\mathrm{\Delta }}^{34}$S values from –4.2‰ to +8.3‰; they also have high Fe_HR/Fe_T ratios from 0.5 to 0.66, that are indicative of a low SO${}_4^{2-}$ content in anoxic seawater. Calcareous shales from Interval I display at least two Hg/TOC peaks (up to 207 ppb/wt%), coincident with volcanic eruptions associated with the ca. 510 Ma Kalkarindji LIP in Australia. In the middle part of the Dongjin section (Interval II), calcareous shales display negative excursions of ${\mathrm{\Delta }}^{199}$Hg values, ${\delta }^{34}$S_Py values and Fe_HR/Fe_T ratios, which were likely led by a large terrestrial input into a marginal basin from where Interval II deposited. Calcareous shales in the upper part of the section (Interval III) contain pyrite framboids with a mean diameter of <4 μm and high ratios of Fe_HR/Fe_T (>0.82) and Fe_Py/Fe_HR (>0.78), indicating an euxinic depositional environment. They also record negative excursions in ${\delta }^{13}$C and ${\delta }^{202}$Hg (with low values down to –3.05‰ and –1.68‰, respectively), providing evidence for ocean upwelling. The negative shift of ${\delta }^{13}$C values in the Dongjin section was temporally comparable to the C isotope excursions that coincided with the Redlichiid-Olenellid Extinction Carbon Isotope Excursion (ROECE). We conclude that volcanic eruptions of the ca. 510 Ma Kalkarindji LIP enhanced the continental erosion rate, leading to a high terrestrial SO${}_4^{2-}$ input and an accumulation of H₂S in deep marginal basins at the end of CS₂. The subsequent ocean upwelling (>506 Ma) brought anoxic/euxinic seawaters into the continental shelf, contributing to the mass extinction of Redlichiid and Olenellid.

三叶虫的首次大规模灭绝发生在从寒武纪系列2（CS ₂）到苗岭期（M）的过渡时期，同时发生了大的海侵和大火成岩省（LIP）的火山喷发。理解这些事件之间的因果关系对于破译当时的环境变化和生命演化非常重要。本文介绍了华南东晋剖面CS ₂ -M杨柳岗组钙质页岩的S-Hg-C同位素和Fe形态数据。在本节的下部（区间I），钙质页岩在碳酸盐伴生的硫酸盐之间具有有限的S同位素差异（${\delta }^{34}$S _CAS）和黄铁矿（${\delta }^{34}$S _Py）与${\mathrm{\Delta }}^{34}$S值从–4.2‰至+ 8.3‰；它们还具有高的Fe _HR / Fe _T比（从0.5到0.66），表明SO低${}_4^{\mathrm{2个}-}$缺氧海水中的含量。区间I的钙质页岩显示至少两个Hg / TOC峰（最高207 ppb / wt％），与与ca关联的火山喷发同时发生。510 Ma Kalkarindji LIP在澳大利亚。在东津断面的中部（第二段），钙质页岩显示负向偏移。${\mathrm{\Delta }}^{199}$汞值 ${\delta }^{34}$S _Py值和Fe _HR / Fe _T比，这可能是由Interval II沉积到边缘盆地的大量陆地输入所引起的。该段上部（区间III）的钙质页岩含有黄铁矿磁石，平均直径<4μm，并且Fe _HR / Fe _T（> 0.82）和Fe _Py / Fe _HR（> 0.78）的比率很高。正常的沉积环境。他们还记录了${\delta }^{13}$C和 ${\delta }^{202}$汞（低值分别降至–3.05‰和–1.68‰），为海洋上升提供了证据。的负移${\delta }^{13}$东津地区的C值在时间上可与与Redlichiid-Olenellid灭绝碳同位素游览（ROECE）吻合的C同位素游览相媲美。我们得出的结论是，约旦河的火山喷发。510 Ma Kalkarindji LIP提高了大陆侵蚀速率，导致陆地SO偏高${}_4^{\mathrm{2个}-}$CS ₂末期边缘盆地的H ₂ S的输入和积累。随后的海洋上升（> 506 Ma）将缺氧/富营养化海水带入了大陆架，导致了赤足纲和O鱼纲的大规模灭绝。