Multiple expansions of C4 plant biomass in East Asia since 7 Ma coupled with strengthened monsoon circulation
- An Zhisheng12,
- Huang Yongsong3,
- Liu Weiguo4,
- Guo Zhengtang4,
- Steven Clemens5,
- Li Li6,
- Warren Prell7,
- Ning Youfeng8,
- Cai Yanjun8,
- Zhou Weijian8,
- Lin Benhai8,
- Zhang Qingle8,
- Cao Yunning8,
- Qiang Xiaoke8,
- Chang Hong8 and
- Wu Zhenkun8
- 1State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, P.O. Box 17, Xi'an 710075, China
- 2Key Laboratory of Environmental Change and Natural Disaster of the Ministry of Education, Beijing Normal University, Beijing 100875, China
- 3Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA
- 4Institute of Earth Environment, Chinese Academy of Sciences, P.O. Box 17, Xi'an 710075, China
- 5Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA
- 6Institute of Earth Environment, Chinese Academy of Sciences, P.O. Box 17, Xi'an 710075, China
- 7Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA
- 8Institute of Earth Environment, Chinese Academy of Sciences, P.O. Box 17, Xi'an 710075, China
Abstract
The expansion of plants using the C4 photosynthetic pathway is one of the most prominent changes in the global ecosystem during the Cenozoic Era. A significant late Miocene expansion is well documented. However, the existence and cause of subsequent expansions are still not clear, owing in part to the lack of long, continuous climate-vegetation records. Here we present two high-resolution carbon isotope time series, covering the past 7 m.y., derived from eolian deposits on the Chinese Loess Plateau. The data indicate three intervals of significant C4 plant expansions within the semiarid monsoonal region of East Asia (ca. 2.9–2.7 Ma, 1.3–0.9 Ma, and 0.6 Ma–present). These expansions covary with strengthened East Asian summer monsoon circulation. We conclude that in East Asia, large-scale late Miocene C4/C3 vegetation changes in semiarid areas have been primarily driven by warm seasonal precipitation and temperature variations associated with changes in monsoon circulation.
Footnotes
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- Accepted 10 May 2005.
- Received 28 December 2004.
- Revision received 9 May 2005.
- Geological Society of America
