Astronomical tuning and magnetostratigraphy of Neogene biogenic reefs in Xisha Islands, South China Sea

Biogenic reefs are one of two major depositional types in the South China Sea, and are constructed by coral, algae and bryozoa. The West Pacific is a major area of biogenic reef development and plays a critical role in the global carbon cycle. However, the lack of geochronological studies in previou...

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Bibliographic Details
Published in:Science Bulletin
Main Authors: Yi, Liang, Jian, Zhimin, Liu, Xinyu, Zhu, Youhua, Zhang, Daojun, Wang, Zhenfeng, Deng, Chenglong
Format: Report
Language:English
Published: SCIENCE PRESS 2018
Subjects:
Astronomical tuning
Magentostratigraphy
Magnetic susceptibility
Biogenic reefs
Neogene
South China Sea
CARBONATE PLATFORMS
OCEAN ACIDIFICATION
NORTHERN MARGIN
CLIMATE-CHANGE
LATE MIOCENE
CORAL-REEFS
ASIA
SEDIMENTATION
EVOLUTION
FRAMEWORK
Science & Technology - Other Topics
Multidisciplinary Sciences
Pacific
Ocean acidification
Online Access:http://ir.nigpas.ac.cn/handle/332004/17186
https://doi.org/10.1016/j.scib.2018.04.001
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Summary:Biogenic reefs are one of two major depositional types in the South China Sea, and are constructed by coral, algae and bryozoa. The West Pacific is a major area of biogenic reef development and plays a critical role in the global carbon cycle. However, the lack of geochronological studies in previous works inhibits our understanding of their contributions. Herein, we conduct a cyclostratigraphic and magnetostratigraphic study on Neogene biogenic reefs using the XK-1 core that was drilled at the Shidao Island, Xisha (Paracel) Islands. The main findings of this study are: (1) the establishment of reliable magentostratigraphy for Ledong, Huangliu, Meishan and Sanya Formations; (2) the magnetic susceptibility variation can be inferred as growth index and tuned to the 405-ka long eccentricity cycle; (3) the astronomical geochronology suggests that the bottom ages for Ledong, Yinggehai, Huangliu, Meishan, and Sanya Formations are 2.2 Ma, 5.7 Ma, 10.4 Ma, 16.6 Ma, and 24.3 Ma, respectively; and (4) Earth's eccentricity and obliquity played predominant roles in biogenic reef establishment on orbital to tectonic timescales. Thus, the reported geochronology offers an opportunity to test the contributions of various factors and hypothesize their roles in the global carbon cycle in future. (C) 2018 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

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