文献类型：期刊文献

英文题名：Oceanic redox condition and the evolution of Ediacaran life: Evidence from nitrogen isotopes and biogenic silica in the Yangtze Block, South China

作者：Wang, Zaiyun[1,2,3];Cao, Hansheng[1,2,3];Chen, Fajin[1,2,3];Wei, Kai[4,5];Bao, Chuang[1,2,3];Hou, Qinghua[1,2,3];Chen, Chunqing[1,2,3];Huang, Hanli[1,2,3];Chen, Qiuping[1,2,3]

机构：[1]Guangdong Ocean Univ, Coll Ocean & Meteorol, Lab Coastal Ocean Variat & Disaster Predict, Zhanjiang 524088, Peoples R China;[2]Guangdong Ocean Univ, Coll Ocean & Meteorol, Key Lab Climate Resources & Environm Continental S, Zhanjiang 524088, Peoples R China;[3]Minist Nat Resources, Key Lab Space Ocean Remote Sensing & Applicat, Beijing 100081, Peoples R China;[4]China Geol Survey, Wuhan Ctr, Geosci Innovat Ctr Cent South China, Wuhan 430205, Peoples R China;[5]China Geol Survey, Hubei Key Lab Paleontol & Geol Environm Evolut, Wuhan Ctr, Wuhan 430205, Peoples R China

年份：2025

卷号：667

外文期刊名：PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY

收录：SCI-EXPANDED(收录号：WOS:001450734300001)、、Scopus(收录号：2-s2.0-105000119363)、WOS

基金：This research is supported by the Guangdong Natural Science Foundation of China (2025A1515012009, 2022A1515012100) , Zhan-jiang City Science and Technology Special Project (2024B01069) .

语种：英文

外文关键词：Ediacaran; Doushantuo Formation; Nitrogen isotope; Chemostratigraphy; Shuram excursion

外文摘要：The late Ediacaran period witnessed the largest global carbon cycle disturbance in geological history, known as the "Shuram Excursion", coinciding with the emergence of early complex multicellular life. While the rise in atmospheric and oceanic oxygen is seen as a major catalyst for this evolutionary leap, the link between oxygenation and Ediacaran diversification remains contested. To investigate this, we reported nitrogen, carbonate, and organic carbon isotopes, as well as biogenic silica (BSi) content from a drill core in the Yangtze Platform, South China. During the lower Shuram excursion, S15N decreased from 5.9 %o to 2.9 %o, suggesting a shrinking nitrate pool in the euphotic zone associated with intensified denitrification due to the expansion of the anoxic zone. During the middle Shuram excursion, a significant decline in S13Ccarb was accompanied by a rapid increase in S15N (up to 5.8 %o), which likely reflects a transitional redox state characterized by moderate denitrification in the water column, enriching the remaining nitrate in the photic zone with 15N. The subsequent decline in S15N signatures likely reflects reduced water-column denitrification, driven by further ocean oxygenation and the deepening of the chemocline. The concurrent positive excursions in S15N and negative S13Ccarb correspond to the peak in BSi contents, suggesting that the rise in seawater O2 levels and the increase in surface nitrate concentrations provided a favorable environment for siliceous organisms. The geochemical signatures observed correspond with the diversification of ecologically important animal groups, emphasizing the accelerated evolution of the Avalon biota in oxygen and nitrate-enriched environments.