The aerobic diagenesis of Mesoproterozoic organic matter
(2018) In Scientific Reports 8(1). p.1-10- Abstract
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... (More)
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.
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- author
- Wang, Xiaomei ; Zhao, Wenzhi ; Zhang, Shuichang ; Wang, Huajian ; Su, Jin ; Canfield, Donald E and Hammarlund, Emma U LU
- publishing date
- 2018-09-06
- type
- Contribution to journal
- publication status
- published
- in
- Scientific Reports
- volume
- 8
- issue
- 1
- article number
- 13324
- pages
- 1 - 10
- publisher
- Nature Publishing Group
- external identifiers
-
- scopus:85052949202
- pmid:30190572
- ISSN
- 2045-2322
- DOI
- 10.1038/s41598-018-31378-6
- language
- English
- LU publication?
- no
- id
- dc9010b4-8ad9-4285-a37a-e928ad21e050
- date added to LUP
- 2019-04-10 16:20:38
- date last changed
- 2024-02-14 22:12:13
@article{dc9010b4-8ad9-4285-a37a-e928ad21e050,
abstract = {{<p>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.</p>}},
author = {{Wang, Xiaomei and Zhao, Wenzhi and Zhang, Shuichang and Wang, Huajian and Su, Jin and Canfield, Donald E and Hammarlund, Emma U}},
issn = {{2045-2322}},
language = {{eng}},
month = {{09}},
number = {{1}},
pages = {{1--10}},
publisher = {{Nature Publishing Group}},
series = {{Scientific Reports}},
title = {{The aerobic diagenesis of Mesoproterozoic organic matter}},
url = {{http://dx.doi.org/10.1038/s41598-018-31378-6}},
doi = {{10.1038/s41598-018-31378-6}},
volume = {{8}},
year = {{2018}},
}