Global trends in nutrient dynamics during the Ediacaran / Cambiran period as revealed in nitrogen isotope signatures

氮同位素特征揭示埃迪卡拉/坎比兰时期营养动态的全球趋势

• 批准号: 45523092
• 负责人: Professor Dr. Ulrich Struck
• 金额: --
• 依托单位: Museum für Naturkunde - Leibniz-Institut für Evolutions- und Biodiversitätsforschung (MfN)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/45523092?language=en
• 关键词: Global; trends; nutrient; dynamics; during

The Ediacaran and the Cambrian periods record remarkably important environmental changes on Earth which are believed to be relevant for the most prominent bioradiation in Earth's history. The transition to a fully oxygenated surface environment occurred during the late Neoproterozoic and is believed to have influenced the nitrogen cycle in terms of the variable availability of nitrogen in reduced (NH4) or oxidised (NO3) forms for primary productivity. Coincident with these variations was the widespread deposition of giant phosphorite- and organic-rich sediments (black shales), notably in China. The previous project has focused to create detailed 15N records of the ~635 to ~500 Ma interval. It documented a strong negative nitrogen isotopic excursion in most of the studied sections from South China during the earliest Cambrian. This excursion is probably linked to the switch between the older small shelly fossil assemblages and the later "typical" fossil association including trilobites, molluscs, echinoderms, sponges and other "modern" type fossils.Based on these results, the proposed project aims to study in detail the nitrogen isotope record of shales and other sedimentary rocks from three well-exposed and well-documented Ediacaran to Early Cambrian sections in South China, closely cooperating with the other geochemical subprojects in a multi-proxy approach so that they can be used as key sections for the reconstruction of biogeochemical and paleoenvlronmental changes during the Precambrian-Cambrian transition. Additionally, samples using the same proxies from the Tarim block of NW China, from Kazakhstan, Spain and Namibia will be integrated in this study for global biogeochemical correlation, albeit at a lower resolution. First results from the Spanish sections indicate the existence of a negative nitrogen isotope excursion during the early Cambrian comparable to that documented from the South China sections. We will also analyze, in cooperation with our Chinese partners, organic and carbonate carbon isotope composition where carbonates are present.The new data, in combination with the existing records, will be integrated with results from paleobiology and stratigraphy to assess their possible role in "feeding" the global radiation event at the PCB.

埃迪卡拉纪和寒武纪时期记录了地球上非常重要的环境变化，这些变化被认为与地球历史上最突出的生物辐射有关。过渡到一个完全氧化的表面环境发生在新元古代晚期，据信已经影响了氮循环方面的可变可用性氮还原（NH 4）或氧化（NO3）形式的初级生产力。与这些变化相一致的是大量富含磷块岩和有机物的沉积物（黑色页岩）的广泛沉积，特别是在中国。上一个项目的重点是创建详细的~635至~500 Ma间隔的15 N记录。在中国南方早寒武世，大部分剖面的氮同位素都出现了强烈的负漂移。这种偏移可能与较老的小壳化石组合和后来的“典型”化石组合（包括三叶虫、软体动物、棘皮动物、海绵和其他“现代”类型化石）之间的转换有关。基于这些结果，建议的项目旨在详细研究三个暴露良好和通过对华南地区埃迪卡拉纪-早寒武世剖面的研究，并与其他地球化学子项目密切合作，采用多指标方法，将其作为恢复前寒武纪-寒武纪过渡期地球化学和古环境变化的关键剖面。此外，使用相同的代理从中国西北部的塔里木地块，从哈萨克斯坦，西班牙和纳米比亚的样品将被整合在这项研究的全球地球化学相关性，虽然在较低的分辨率。来自西班牙部分的第一个结果表明，存在一个负的氮同位素漂移在早寒武世与华南部分的记录。我们还将与中国合作伙伴合作，分析碳酸盐存在地区的有机碳和碳酸盐碳同位素组成，结合现有记录，将新数据与古生物学和地层学结果相结合，以评估它们在PCB全球辐射事件中的可能作用。

项目成果

Nitrogen and organic carbon isotope stratigraphy of the Yangtze Platform during the Ediacaran-Cambrian transition in South China

• DOI: 10.1016/j.palaeo.2013.12.016
• 发表时间: 2014-03-15
• 期刊: PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
• 影响因子: 3
• 作者: Cremonese, Lorenzo;Shields-Zhou, Graham A.;Och, Lawrence M.
• 通讯作者: Och, Lawrence M.

Marine redox variations and nitrogen cycle of the early Cambrian southern margin of the Yangtze Platform, South China: Evidence from nitrogen and organic carbon isotopes

华南扬子地台南缘早寒武世海洋氧化还原变化与氮循环：来自氮和有机碳同位素的证据

• DOI: 10.1016/j.precamres.2015.06.009
• 发表时间: 2015-09
• 期刊: PRECAMBRIAN RESEARCH
• 影响因子: 3.8
• 作者: Wang Dan;Struck Ulrich;Ling Hong-Fei;Guo Qing-Jun;Shields-Zhou Graham A.;Zhu Mao-Yan;Yao Su-Ping
• 通讯作者: Yao Su-Ping