The end-Triassic extinction event (ETE) marks one of the “Big five” mass extinction events of the Phanerozoic, yet the timing and nature of environmental changes on a global scale remain elusive. Here we report a mm-scale high-resolution δ³⁰Si profile of sea surface-dwelling radiolaria, preserved as moulds, spanning the end-Triassic radiolarian turnover interval of the deep-sea succession at the Katsuyama section, Inuyama, Japan. The δ³⁰Si of the Triassic-Jurassic radiolaria between − 0.6 ± 0.5‰ and 2.6 ± 0.3‰ overlap with available radiolarian δ³⁰Si data for Triassic to Cenozoic, including modern samples. The mass balance of Si with dominant radiolaria up to 90% in chert supports negligible impact of diagenesis on δ³⁰Si of radiolarian moulds. The cm-scale δ³⁰Si variations up to 2 ‰ are overall associated with changes in silica contents. Here we hypothesize that the δ³⁰Si of radiolarian reflect radiolarian productivity. We detected negative silicon isotope excursions within and above the end-Triassic radiolarian turnover interval, named here the SIE 1 and 2. The first SIE of 2 ‰ is detected from 0 mm to 10 mm above the base of purple chert interval, probably linked with the initial massive volcanism in the Central Atlantic magmatic provinces (CAMP) and associated deep-sea acidification and the onset of the end-Triassic radiolarian turnover. Subsequent positive SIE up to 2 ‰ ca. 10 mm above the first negative SIEs may record recovery of biosiliceous productivity, which could may be related with the first appearance of several Jurassic radiolarian taxa within the radiolarian turnover interval. We also detected data that is suggestive of SIE 2 in the lowermost dusky red chert bed, suggesting similar changes in productivity. These negative SIEs occurred within ~ 1 mm interval, implying the occurrence of kyr- or shorter-scale drastic environmental perturbations across the end-Triassic radiolarian turnover interval.

三叠纪末灭绝事件（ETE）标志着显生宙“五巨头”大规模灭绝事件之一，但全球范围内环境变化的时间和性质仍然难以捉摸。在这里，我们报告了以模具形式保存的海面放射虫的毫米级高分辨率 δ ³⁰ Si 剖面，跨越日本犬山 Katsuyama 剖面深海层序的三叠纪末放射虫周转区间。三叠纪-侏罗纪放射虫的 δ ³⁰ Si 在 - 0.6 ± 0.5‰ 和 2.6 ± 0.3‰ 之间与可用的三叠纪至新生代放射虫 δ ³⁰ Si 数据重叠，包括现代样本。Si 与主要放射虫在燧石中高达 90% 的质量平衡支持成岩作用对 δ ^{30的影响可以忽略不计}放射虫模具的 Si。高达 2 ‰的厘米级 δ ³⁰ Si 变化总体上与二氧化硅含量的变化有关。这里我们假设 δ ³⁰放射虫的 Si 反映放射虫的生产力。我们在三叠纪末放射虫周转区间内和上方检测到负硅同位素偏移，在此命名为 SIE 1 和 2。在紫燧石区间底部上方 0 毫米到 10 毫米处检测到第一个 2‰的 SIE，可能与中大西洋岩浆区（CAMP）最初的大规模火山活动和相关的深海酸化以及三叠纪末放射虫周转的开始。随后的阳性 SIE 高达 2 ‰ ca。在第一个负 SIE 上方 10 mm 可能记录生物硅生产力的恢复，这可能与放射虫周转区间内首次出现几个侏罗纪放射虫类群有关。我们还在最下方的暗红色燧石床中检测到暗示 SIE 2 的数据，暗示生产力的类似变化。这些负 SIE 发生在约 1 毫米的区间内，这意味着在三叠纪末放射虫周转区间发生了 kyr 或更短尺度的剧烈环境扰动。