国家冰川冻土沙漠科学数据中心

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名称	Interpretation of abnormally negative carbon isotope excursions in Eifelian–Givetian (Middle Devonian) sediments of South China and implications for paleo-environmental variation. (华南中泥盆世埃菲尔阶至吉维特阶沉积物异常负偏碳同位素的成因及其对古环境变化的指示)
科技资源标识	CSTR:11738.14.NCDC.XDA14.PP4460.2024
DOI	10.1016/j.palaeo.2022.111225
数据共享方式	开放下载
摘要	Many negative carbon isotope excursions (NCIEs) have been employed to interpret global biogeochemical events in Earth history, but they are also influenced by local depositional settings and diagenetic alteration, thus making it difficult to link them to global events. Like the NCIEs in Middle Devonian sediments of North America, similar NCIEs were also observed in the age-equivalent sediments of South China, and therefore it is necessary to further address the logical significance of these intercontinentally comparable NCIEs. Here, we present major and trace elements as well as δ15N, δ13Ccarb, and δ13Corg records across the Middle Devonian Eifelian–Givetian transition in the intra-platform basin of South China. The changes in stable isotopes (δ13Ccarb, δ13Corg, δ18Ocarb, and δ15N) and their relationships may jointly indicate limited influence of diagenetic processes. Our abnormally negative δ13Ccarb values (—7 to —5‰), even lighter than the mantle input end-member value (~ —5‰), cannot be easily explained by dramatic changes in the δ C values of global dissolved inorganic carbon (DIC) reservoir. In a restricted platform basin, enhanced nutrient input may stimulate high paleo-productivity, resulting in the depletion of DIC concentrations in surface waters. CO2 is then replenished via invasion from the atmosphere, and intense evaporative conditions may promote the large isotopic fractionation of CO2 invasion owing to hydration reactions of aqueous CO2. Our NCIEs are most likely related to the local 13C-depleted values of platform DIC owing to CO2 invasion associated with large isotopic fractionation due to enhanced evaporation and primary productivity. The “productivity-anoxia feedback” mechanism can explain the coupled changes in our terrestrial clastics input, productivity, and redox proxies. By combining redox proxies and C and N isotopic records, we further propose a model for local carbon and nitrogen cycling in a restricted and evaporative intra-platform basin. Our study highlights local depositional controls on NCIEs, and these local factors should be considered before NCIEs are applied to understand the global carbon cycle perturbations during the Middle Devonian.
学科分类	170.50
关键词	Negative carbon isotope excursion Middle DevonianDiagenetic alteration Redox stratified Nitrogen cycle Restricted basin
作者	Wu yaowen
数据量	11.2 MiB
论文类型：	journal
论文网址：	https://doi.org/10.1016/j.palaeo.2022.111225
期刊名称：	Palaeogeography, Palaeoclimatology, Palaeoecology
出版时间：	2022-10-15

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数据引用

Wu yaowen. Interpretation of abnormally negative carbon isotope excursions in Eifelian–Givetian (Middle Devonian) sediments of South China and implications for paleo-environmental variation. (华南中泥盆世埃菲尔阶至吉维特阶沉积物异常负偏碳同位素的成因及其对古环境变化的指示). 国家冰川冻土沙漠科学数据中心(http://www.ncdc.ac.cn), 2024. https://cstr.cn/CSTR:11738.14.NCDC.XDA14.PP4460.2024.

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本作品采用知识共享署名 4.0 国际许可协议进行许可。

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项目信息详情

项目名称：深层油气形成与分布预测
项目编号：XDA14010000
项目类别：中国科学院战略性先导科技专项（A类）