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The aerobic diagenesis of Mesoproterozoic organic matter
The Xiamaling Formation in the North China Block contains a well-preserved 1400 Ma sedimentary sequence with a low degree of thermal maturity. Previous studies have confirmed the dynamic and complex nature of this evolving marine setting, including the existence of an oxygen-minimum zone, using mult...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6127340/ https://www.ncbi.nlm.nih.gov/pubmed/30190572 http://dx.doi.org/10.1038/s41598-018-31378-6 |
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author | Wang, Xiaomei Zhao, Wenzhi Zhang, Shuichang Wang, Huajian Su, Jin Canfield, Donald E. Hammarlund, Emma U. |
author_facet | Wang, Xiaomei Zhao, Wenzhi Zhang, Shuichang Wang, Huajian Su, Jin Canfield, Donald E. Hammarlund, Emma U. |
author_sort | Wang, Xiaomei |
collection | PubMed |
description | The Xiamaling Formation in the North China Block contains a well-preserved 1400 Ma sedimentary sequence with a low degree of thermal maturity. Previous studies have confirmed the dynamic and complex nature of this evolving marine setting, including the existence of an oxygen-minimum zone, using multi-proxy approaches, including iron speciation, trace metal dynamics, and organic geochemistry. Here, we investigate the prevailing redox conditions during diagenesis via the biomarkers of rearranged hopanes from the finely laminated sediments of the organic-rich black shales in Units 2 and 3 of the Xiamaling Formation. We find that rearranged hopanes are prominent in the biomarker composition of the oxygen-minimum zone sediment, which is completely different from that of the sediment in the overlying anoxic strata. Since the transition process from hopanes to rearranged hopanes requires oxygen via oxidation at the C-l6 alkyl position of 17α(H)-hopanes, we infer that dissolved oxygen led to the transformation of hopane precursors into rearranged hopanes during the early stages of diagenesis. The use of hopanoid hydrocarbons as biomarkers of marine redox conditions has rarely been previously reported, and the hydrocarbon signatures point towards oxic bottom waters during the deposition of Unit 3 of the Xiamaling Formation, which is consistent with the earlier oxygen-minimum zone environmental interpretation of this Unit. |
format | Online Article Text |
id | pubmed-6127340 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-61273402018-09-10 The aerobic diagenesis of Mesoproterozoic organic matter Wang, Xiaomei Zhao, Wenzhi Zhang, Shuichang Wang, Huajian Su, Jin Canfield, Donald E. Hammarlund, Emma U. Sci Rep Article The Xiamaling Formation in the North China Block contains a well-preserved 1400 Ma sedimentary sequence with a low degree of thermal maturity. Previous studies have confirmed the dynamic and complex nature of this evolving marine setting, including the existence of an oxygen-minimum zone, using multi-proxy approaches, including iron speciation, trace metal dynamics, and organic geochemistry. Here, we investigate the prevailing redox conditions during diagenesis via the biomarkers of rearranged hopanes from the finely laminated sediments of the organic-rich black shales in Units 2 and 3 of the Xiamaling Formation. We find that rearranged hopanes are prominent in the biomarker composition of the oxygen-minimum zone sediment, which is completely different from that of the sediment in the overlying anoxic strata. Since the transition process from hopanes to rearranged hopanes requires oxygen via oxidation at the C-l6 alkyl position of 17α(H)-hopanes, we infer that dissolved oxygen led to the transformation of hopane precursors into rearranged hopanes during the early stages of diagenesis. The use of hopanoid hydrocarbons as biomarkers of marine redox conditions has rarely been previously reported, and the hydrocarbon signatures point towards oxic bottom waters during the deposition of Unit 3 of the Xiamaling Formation, which is consistent with the earlier oxygen-minimum zone environmental interpretation of this Unit. Nature Publishing Group UK 2018-09-06 /pmc/articles/PMC6127340/ /pubmed/30190572 http://dx.doi.org/10.1038/s41598-018-31378-6 Text en © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
spellingShingle | Article Wang, Xiaomei Zhao, Wenzhi Zhang, Shuichang Wang, Huajian Su, Jin Canfield, Donald E. Hammarlund, Emma U. The aerobic diagenesis of Mesoproterozoic organic matter |
title | The aerobic diagenesis of Mesoproterozoic organic matter |
title_full | The aerobic diagenesis of Mesoproterozoic organic matter |
title_fullStr | The aerobic diagenesis of Mesoproterozoic organic matter |
title_full_unstemmed | The aerobic diagenesis of Mesoproterozoic organic matter |
title_short | The aerobic diagenesis of Mesoproterozoic organic matter |
title_sort | aerobic diagenesis of mesoproterozoic organic matter |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6127340/ https://www.ncbi.nlm.nih.gov/pubmed/30190572 http://dx.doi.org/10.1038/s41598-018-31378-6 |
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