It has been disputed whether volcanic activity promotes the enrichment of organic matter in geological periods. In a biostratigraphic framework, this study divided the volcanic eruption periods during the Ordovician-Silurian transition in western Hubei Province based on the longitudinal differentiation of the bentonite development, analyzed the sedimentological and geochemical characteristics of each eruption period, and explored the relationship between the volcanic activity and the organic matter enrichment. The results show that from early to late, the Ordovician-Silurian transition can be divided into 1) a strong eruption period (lower Wufeng) that was mainly dominated by carbonaceous shale deposits (containing both terrigenous silicon and biological silicon, with a medium organic matter content), which corresponded to a stage of strong flexural subsidence; 2) a weak eruption period (Wufeng-Longmaxi transition) that was dominated by organic-rich and biogenic silica-rich siliceous shale deposits, which corresponded to a stage of stable flexural subsidence; 3) a strong eruption period (lower Longmaxi) that was dominated by carbonaceous shale deposits with a medium organic matter content, which involved major changes in the paleogeographic pattern and corresponded to an initial stage of flexural migration wherein the depositional water body became shallow; and 4) a strong eruption period (upper Longmaxi) dominated by organic-poor, terrigenous silica-rich argillaceous shale deposits, which corresponded to a stage of expanded flexural migration wherein the depositional water body became even shallower. The strength of the volcanic activity was closely associated with the differential enrichment of the organic matter. The tectonic activity was stable in the period of weak volcanic activity, which was characterized by low terrigenous inputs, moderate water restriction, and a high paleo-productivity. This was favorable for organic matter enrichment, thereby leading to a high TOC content. During the periods of violent volcanic activity, the Cathaysia Block collided violently with the Yangtze blocks, resulting in more terrigenous input, a higher degree of water restriction, a shallower depositional water body, and a lower paleo-productivity, which had a significant inhibitory effect on the organic matter enrichment. This inhibitory effect was larger than the promotional effect of the volcanic ash on the organic matter enrichment, thereby resulting in a decrease in the TOC content.

火山活动是否促进了地质时期有机质的富集一直存在争议。本研究在生物地层框架下，根据膨润土发育的纵向分异划分鄂西奥陶系-志留系火山喷发期，分析各喷发期的沉积学和地球化学特征，探讨火山喷发期与火山喷发期之间的关系。活性和有机质富集。结果表明，奥陶系—志留系过渡期从早到晚可划分为：1）以碳质页岩为主（含陆源硅和生物硅，有机质中等）的强喷发期（五峰下段）内容），这对应于强烈的弯曲下沉阶段；2）弱喷发期（五峰-龙马溪过渡期），以富含有机质和生物成因的硅质页岩沉积为主，对应稳定弯曲沉降阶段；3）强喷发期（龙马溪下段），以碳质页岩沉积为主，有机质含量中等，古地理格局变化较大，对应沉积水体变浅的弯曲运移初期；4）以贫有机质、陆源富硅泥质页岩沉积为主的强喷发期（龙马溪上游），对应于弯曲运移扩大阶段，沉积水体变得更浅。火山活动的强弱与有机质的差异富集密切相关。火山活动弱期构造活动稳定，具有陆源输入量低、限水适度、古生产力高的特点。这有利于有机物的富集，从而导致高 TOC 含量。在剧烈的火山活动期间，华夏地块与扬子地块发生剧烈碰撞，导致陆源输入更多，限水程度更高，沉积水体更浅，古生产力较低，抑制作用显着关于有机质富集。这种抑制作用大于火山灰对有机质富集的促进作用，