文献类型：期刊文献

英文题名：Application of Nitrogen Isotopic Systematics in Different N Forms for the Reconstruction of Redox Conditions: An Example From the Songliao Basin

作者：Cao, Hansheng[1,2,3];Wang, Zaiyun[1,2,3];Chen, Fajin[1,2,3];Chen, Chunqing[1,2,3];Hu, Liumei[1,2,3]

机构：[1]Guangdong Ocean Univ, Coll Ocean & Meterol, Lab Coastal Ocean Variat & Disaster Predict, Zhanjiang, Peoples R China;[2]Guangdong Ocean Univ, Coll Ocean & Meteorol, Key Lab Climate Resources & Environm Continental, Zhanjiang, Peoples R China;[3]Minist Nat Resources, Key Lab Space Ocean Remote Sensing & Applicat, Beijing, Peoples R China

年份：2022

卷号：37

期号：12

外文期刊名：PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY

收录：SCI-EXPANDED(收录号：WOS:000924588400001)、、EI(收录号：20242816665956)、Scopus(收录号：2-s2.0-85145232625)、WOS

基金：This research is supported by the National Natural Science Foundation of China (NSFC) (41903067, U1901213), Guangdong Natural Science Foundation of China (2022A1515012100, 2019B1515120066), South China Sea Scholar Project of Guangdong Ocean University (002029002007), Guangdong Provincial College Innovation Team Project (2019KCXTF021), First-class Discipline Plan of Guangdong Province (080503032101, 231420003).

语种：英文

外文关键词：Decomposition - Denitrification - Extraction - Isotopes - Sedimentology - Water

外文摘要：The assessment of nitrogen cycle processes in paleomarine and paleolake systems commonly relies solely on total nitrogen isotopes. If organic nitrogen and adsorbed nitrate can be effectively extracted from samples, the application of nitrogen isotopic systematics in different N forms would be beneficial for reconstructing the nitrogen cycle process in pore water and would mutually complement water chemistry information. According to the variations in delta C-13(org), delta N-15(TN), delta N-15(org) and delta N-15(nitrate) data of the Cretaceous Nenjiang Formation in the Songliao Basin, NE China, the profile could be divided into three intervals (intervals A-C). We attribute the anomalously high delta N-15(nitrate) (similar to+20) from intervals A and C to the effect of sedimentary denitrification that occurred in the benthic sediments during the early diagenetic stage. We also recognize the intimate relationship between delta N-15(nitrate) and delta N-15(org) values, which are interpreted to reflect the effect of water column denitrification in the bottom waters and/or surface pore water. Based on the comparison of nitrogen isotope variability and the evolving environmental context, we interpret the water column denitrification as primarily reflecting anoxic bottom water or surface pore waters, while the sedimentary denitrification indicated by abnormally high delta N-15(nitrate) can effectively represent oxic bottom water. This study not only reveals that the adsorbed nitrate can be well extracted from mudstones with low thermal decomposition degrees but also suggests that the organic nitrogen-nitrate isotope proxies can be used as a potential parameter to track the redox structure in water masses.