Stratigraphic records of impact ejecta preserved in a pelagic deep-sea setting occur within Upper Triassic successions of the subduction-generated accretionary complexes of central Japan. A significant biotic turnover in radiolarians occurred during the ~ 300 kyr time interval after the impact event, which is characterized by a remarkable reduction in the burial flux of radiolarian silica. However, the nature of the environmental conditions at this time remains unclear. To investigate the environmental changes that triggered a decline in radiolarian burial flux after the impact event, geochemical proxies (major, trace, and rare earth elements) were applied to the middle–upper Norian (Upper Triassic) bedded chert succession of the Mino Belt, central Japan. A progressive environmental deterioration is evident from (1) a post-impact shutdown of burial flux of primary and silica- and apatite-secreting organisms; and (2) a subsequent abrupt increase in chemical weathering associated with a sustained reduction in the burial flux of radiolarian silica. No significant redox changes were observed across the impact event. The continental weathering proxies suggest a transient increase in weathering intensity occurred during the decline of radiolarian burial flux, likely in response to a short-term warm and humid period. Our results delineate a remarkable record of progressive environmental changes in the Panthalassa Ocean after this large impact event.

在日本中部俯冲生成的增生复合体的上三叠纪演替中，发生了在远洋深海环境中保存的撞击射出物的地层学记录。撞击事件发生后约300年的时间间隔内，放射虫发生了重大的生物更新，其特征是放射虫二氧化硅的埋葬通量显着降低。但是，此时环境条件的性质仍不清楚。为了调查在发生撞击事件后触发放射l葬通量下降的环境变化，将地球化学代理（主要，痕量和稀土元素）应用于美浓带的中上诺里安（上三叠纪）层状石演替，日本中部。从以下方面可以明显看出环境的逐步恶化：（1）初级，分泌二氧化硅和磷灰石的生物在葬礼后受到撞击；（2）随后，化学耐候性突然增加，放射性radio石二氧化硅的埋藏量持续减少。在整个冲击事件中均未观察到明显的氧化还原变化。大陆的风化代理表明，在放射虫的埋葬通量下降期间，风化强度发生了短暂的增加，这可能是对短期的温暖和潮湿时期的反应。我们的结果描绘了在这次大型撞击事件之后潘塔拉萨海洋中不断变化的环境变化的非凡记录。（2）随后，化学耐候性突然增加，放射性radio石二氧化硅的埋藏量持续减少。在整个冲击事件中均未观察到明显的氧化还原变化。大陆的风化代理表明，在放射虫的埋葬通量下降期间，风化强度发生了短暂的增加，这可能是对短期的温暖和潮湿时期的反应。我们的结果描绘了在这次大型撞击事件之后潘塔拉萨海洋中不断变化的环境变化的非凡记录。（2）随后，化学耐候性突然增加，放射性radio石二氧化硅的埋藏量持续减少。在整个冲击事件中均未观察到明显的氧化还原变化。大陆的风化代理表明，在放射虫的埋葬通量下降期间，风化强度发生了短暂的增加，这可能是对短期的温暖和潮湿时期的反应。我们的结果描绘了在这次大型撞击事件之后潘塔拉萨海洋中不断变化的环境变化的非凡记录。