Source of silica and its implications for organic matter enrichment in the Upper Ordovician-Lower Silurian black shale in western Hubei Province, China: Insights from geochemical and petrological analysis

• DOI: 10.1016/j.petsci.2021.10.012
• Publication Date: 2021-10-25T18:53:35Z
• Authors: Quan-Sheng Cai; Ming-Yi Hu; Bao-Min Zhang; Ngong Ngia; An Liu; Rui-Quan Liao; Oumar Kane; Hai Li; Zhong-Gui Hu; Qing-Jie Deng; Jun-Jun Shen
• Keywords: Terrigenous sediment; Siliciclastic; Biogenic silica

To improve the understanding of relationship between silica source and organic matter accumulation, origin its implications for enrichment in Upper Ordovician-Lower Silurian (O3w-S1l) black shale western Hubei Province middle Yangtze area, were investigated through geochemical petrological analyses. The results show that O3w-S1l is mainly composed five lithofacies with varying graptolite abundance, total carbon (TOC), contents. Biogenic terrigenous siliciclastic input constitute main sources they exhibit an upward inverse variation trend interpreted to be related sea-level changes. Moreover, increase biogenic content or decrease input, TOC values initially rise then fall, which different from originally expected simple linear relationship. We infer distribution origins are controlled by changes variations a continental shelf little hydrothermal influence. An environment appropriate sea level should most favorable rather than one excessive high less input.