华南西部晚二叠世碳同位素地层学研究

对黔桂地区７条晚二叠世碳酸盐岩型煤系剖面进行了碳酸盐岩碳氧同位素测定，发现晚二叠世吴家坪阶与长兴阶碳酸盐岩的δ１３Ｃ值有明显差异，前者δ１３Ｃ多大于３．０‰，后者多小于３．０‰，进一步对晚二叠世δ１３Ｃ的变化原因的分析表明，δ１３Ｃ的变化可能与晚古生代末期聚煤作用的减弱密切相关，后者造成自然界碳库中的１２Ｃ的富集，从而使得海水以及在其中沉淀出的碳酸盐岩中的δ１３Ｃ值降低。此外，植物光合作用从大气中吸收ＣＯ２的量也随陆地植被减少而减少，结果造成大气中的ＣＯ２的大量富集，从而进一步产生温室效应，制约生物界的发展。联系到这一阶段生物界的衰亡灭绝，可以认为温室效应是晚二叠世生物逐渐衰亡及晚二叠世末群体灭绝的主要原因之一。

Research on isotope stratigraphy of the Late Permian in Southern China

In this paper, the δ 13 C and δ 18 O values of carbonates from seven Late Permian coal bearing sections in the Guizhou-Guangxi region, Southern China are measured and their stratigraphical implications are discussed. The results show a distinct difference of δ 13 C between Wujiaping Stage and Changxing Stage, the δ 13 C values of the former are mostly higher than 3.0‰,and those of the latter less than 3.0‰. Further analyses show that the change of the δ 13 C values may bear some relation to the green house effect, which may resulted in the release of the CO 2 into atmosphere by oxidizing buried coal and organic matter. The Late Permian is just a transitional period between Late Palaeozoic Ice House Period (marked by the Pemo Carboniferous Gondwana glacier growth ) and the Mesozoic Green House Preiod. Considering the mass extinction of organisms at the end of the Palaeozoic, it can be suggested that the green house effect is one of the main causes of the organsim′s decline in the Late Permian and the mass extinction at the end of the Late Permian.