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. 2014 Dec 12:4:7463.
doi: 10.1038/srep07463.

Synchronous turnover of flora, fauna, and climate at the Eocene-Oligocene Boundary in Asia

Jimin Sun  1 , Xijun Ni  2 , Shundong Bi  2 , Wenyu Wu  2 , Jie Ye  2 , Jin Meng  3 , Brian F Windley  4
Affiliations

Synchronous turnover of flora, fauna, and climate at the Eocene-Oligocene Boundary in Asia

Jimin Sun et al. Sci Rep. .

Abstract

The Eocene-Oligocene Boundary (~34 million years ago) marks one of the largest extinctions of marine invertebrates in the world oceans and of mammalian fauna in Europe and Asia in the Cenozoic era. A shift to a cooler climate across this boundary has been suggested as the cause of this extinction in the marine environment, but there is no manifold evidence for a synchronous turnover of flora, fauna and climate at the Eocene-Oligocene Boundary in a single terrestrial site in Asia to support this hypothesis. Here we report new data of magnetostratigraphy, pollen and climatic proxies in the Asian interior across the Eocene-Oligocene Boundary; our results show that climate change forced a turnover of flora and fauna, suggesting there was a change from large-size perissodactyl-dominant fauna in forests under a warm-temperate climate to small rodent/lagomorph-dominant fauna in forest-steppe in a dry-temperate climate across the Eocene-Oligocene Boundary. These data provide a new terrestrial record for this significant Cenozoic environmental event.

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Figures

Figure 1
Figure 1. Map showing the Junggar Basin and the location of the studied section in China.
(a), Location of the Junggar Basin. (b), Geological map and the location of the Keziletuogayi section. (Maps was drawn by Jimin Sun using the Software of Canvas 8.0.2).
Figure 2
Figure 2. Lithology and the magnetostratigraphy of the Keziletuogayi section.
(a), The lithology of the section. (b), Photo showing the boundary (indicated by the red arrow) of the Late Eocene and Early Oligocene strata. (c), Magnetostratigraphy and mammalian fossils zones (A1 to A3) of the Keziletuogayi section. (Photo was taken by Jimin Sun).
Figure 3
Figure 3. Fauna and Flora records from the Latest Eocene to the Early Oligocene in the Keziletuogayi section.
(a), Mammalian faunas of the section, noting the distinct mammalian turnover across the Eocene–Oligocene Boundary, CLMA: Chinese Land Mammal Ages; ALMA: Asian Land Mammal Ages. (b), Vegetation changed from forests to forest-steppe environment after the beginning of the Oligocene.
Figure 4
Figure 4. Paleoclimatic changes indicated by various climatic proxies.
(a), Variations of kaolinite versus depth. (b), Vertical fluctuations of color index of redness (a*). (c), Variations of Fe2O3 content of the Keziletuogayi section. (d) and (e), High-resolution curves of the redness (a*) and the Fe2O3 content across the Eocene–Oligocene Boundary. Red arrow indicates the variation trend at the Eocene–Oligocene Boundary.
See this image and copyright information in PMC

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