Magnetic Properties and Initiation of Biogenic Reefs in Xisha Islands, South China Sea, at the Oligo–Miocene Boundary
Biogenic reefs and carbonate platforms are valuable natural resources, playing an important role in modulating the global climate and in carbon cycles through biological processes. Biogenic reefs in the Xisha (Paracel) Islands began in the late Oligocene and covaried with the deep-sea basin of the S...
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MDPI AG
2021-09-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/9/9/1031 |
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| author | Yibing Li Xinyu Liu Weiwei Chen Liang Yi |
| author_facet | Yibing Li Xinyu Liu Weiwei Chen Liang Yi |
| author_sort | Yibing Li |
| collection | DOAJ |
| description | Biogenic reefs and carbonate platforms are valuable natural resources, playing an important role in modulating the global climate and in carbon cycles through biological processes. Biogenic reefs in the Xisha (Paracel) Islands began in the late Oligocene and covaried with the deep-sea basin of the South China Sea and with the aeolian deposit in the Chinese Loess Plateau. Core XK-1 was drilled into the Xisha Islands to their granitic base and well dated by magnetostratigraphy, offering an opportunity to reveal the details of how the Xisha reefs initiated. In this report, the lower section of the biogenic reefs (23.0–24.5 Ma) was sampled for studying magnetic properties. The main results are as follows: (1) magnetic minerals in the XK-1 biogenic reefs are dominated by low-coercivity and relatively coarse-grained magnetite; (2) the variabilities of magnetic parameters can be clustered into two sections around 23.6 Ma, and the differences between the two units are evident both in the amplitudes and the means; and (3) changes in the concentration-dependent magnetic parameters can be well correlated with the records of global deep-sea oxygen and carbon isotopes, and the sea level during the Oligo–Miocene boundary. Based on these results, a close link was inferred between biogenic reef evolution in the Xisha Islands and global climate change. This link likely highlights the covariation or the dominant role of the Asian monsoon in biogenic reefs and involves different responses to global temperature, CO<sub>2</sub>, and sea-level changes on various timescales. Therefore, we proposed that the origin of biogenic reefs in the Xisha Islands was likely paced by orbital obliquity from a long-term perspective. |
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| language | English |
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| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-bc1212e643e843aa8096f983d4f672082023-11-22T13:47:03ZengMDPI AGJournal of Marine Science and Engineering2077-13122021-09-0199103110.3390/jmse9091031Magnetic Properties and Initiation of Biogenic Reefs in Xisha Islands, South China Sea, at the Oligo–Miocene BoundaryYibing Li0Xinyu Liu1Weiwei Chen2Liang Yi3State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, ChinaChina National Offshore Oil Corporation Ltd., Hainan Branch, Haikou 570100, ChinaState Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, ChinaState Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, ChinaBiogenic reefs and carbonate platforms are valuable natural resources, playing an important role in modulating the global climate and in carbon cycles through biological processes. Biogenic reefs in the Xisha (Paracel) Islands began in the late Oligocene and covaried with the deep-sea basin of the South China Sea and with the aeolian deposit in the Chinese Loess Plateau. Core XK-1 was drilled into the Xisha Islands to their granitic base and well dated by magnetostratigraphy, offering an opportunity to reveal the details of how the Xisha reefs initiated. In this report, the lower section of the biogenic reefs (23.0–24.5 Ma) was sampled for studying magnetic properties. The main results are as follows: (1) magnetic minerals in the XK-1 biogenic reefs are dominated by low-coercivity and relatively coarse-grained magnetite; (2) the variabilities of magnetic parameters can be clustered into two sections around 23.6 Ma, and the differences between the two units are evident both in the amplitudes and the means; and (3) changes in the concentration-dependent magnetic parameters can be well correlated with the records of global deep-sea oxygen and carbon isotopes, and the sea level during the Oligo–Miocene boundary. Based on these results, a close link was inferred between biogenic reef evolution in the Xisha Islands and global climate change. This link likely highlights the covariation or the dominant role of the Asian monsoon in biogenic reefs and involves different responses to global temperature, CO<sub>2</sub>, and sea-level changes on various timescales. Therefore, we proposed that the origin of biogenic reefs in the Xisha Islands was likely paced by orbital obliquity from a long-term perspective.https://www.mdpi.com/2077-1312/9/9/1031biogenic reefsXisha (Paracel) Islandsclimate changelate Oligoceneearly Mioceneorbital forcing |
| spellingShingle | Yibing Li Xinyu Liu Weiwei Chen Liang Yi Magnetic Properties and Initiation of Biogenic Reefs in Xisha Islands, South China Sea, at the Oligo–Miocene Boundary Journal of Marine Science and Engineering biogenic reefs Xisha (Paracel) Islands climate change late Oligocene early Miocene orbital forcing |
| title | Magnetic Properties and Initiation of Biogenic Reefs in Xisha Islands, South China Sea, at the Oligo–Miocene Boundary |
| title_full | Magnetic Properties and Initiation of Biogenic Reefs in Xisha Islands, South China Sea, at the Oligo–Miocene Boundary |
| title_fullStr | Magnetic Properties and Initiation of Biogenic Reefs in Xisha Islands, South China Sea, at the Oligo–Miocene Boundary |
| title_full_unstemmed | Magnetic Properties and Initiation of Biogenic Reefs in Xisha Islands, South China Sea, at the Oligo–Miocene Boundary |
| title_short | Magnetic Properties and Initiation of Biogenic Reefs in Xisha Islands, South China Sea, at the Oligo–Miocene Boundary |
| title_sort | magnetic properties and initiation of biogenic reefs in xisha islands south china sea at the oligo miocene boundary |
| topic | biogenic reefs Xisha (Paracel) Islands climate change late Oligocene early Miocene orbital forcing |
| url | https://www.mdpi.com/2077-1312/9/9/1031 |
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