中国典型泥炭区现代植物的碳、氧同位素组成及在古环境研究中的意义

The Carbon and Oxygen Isotope Composition of Modern Plants from Typical Peat Bogs in China and Its Significance on the Palaeoclimatic Study

本文测定了中国 3个典型泥炭沼泽四川红原、吉林金川和哈尼的现代沼泽植物中的碳、氧同位素组成。吉林金川和哈尼的沼泽在相似的气候和环境条件下发育演化 ,而四川红原的泥炭发育在截然不同的气候条件下。结果表明 ,每个泥炭沼泽现代植物中的碳、氧同位素均有较大的离散度 ,表现为不同营养状况下的成沼植物之间的同位素差异 ;从δ1 3C值来看 ,三个沼泽中的植物均属C3植物 ;红原与金川、哈尼有着明显不同的现代植物稳定氧同位素组成 ,前者更富集1 8O。同一泥炭植物碳、氧同位素的不均一性要求在利用泥炭沉积物恢复过去气候变化方面一定要谨慎。非常有意义的是贫营养泥炭 (高位泥炭 )的成沼植物有着非常接近的同位素组成 。

The Carbon and oxygen isotope compositions of the modern plants from Hongyuan, Jinchuan and Hani were analyzed. The Jinchuan and Hani peat bogs were developed in similar climate and environment, and the Hongyuan peat bog was formed in a different condition. The Carbon and oxygen isotopic values show big difference among various plants in each peat bog and all plants are of C3 plants. The plants from Hongyuan are enriched in 18 O against those from Jinchuan and Hani, indicating the isotopic difference in various developing environments. The disparity of isotopic composition requires much caution in palaeoclimatic reconstruction with peat. It is very interesting that various oligotrophic plants have identical isotopic values, revealing that the oligotrophic peat may be as an ideal archive for resolving paleoclimatic signals.