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根据海相和陆相记录定量重建白垩纪大气CO2含量对于深入了解这一时期的“温室气候条件”尤为重要,但目前多个阶段的古植物数据还非常有限.基于气孔指数技术,本文根据黑龙江嘉荫永安村组3个层位的铁线蕨型银杏化石表皮,重建了晚白垩世三冬期大气CO2含量.回归法分析的结果显示,三冬期CO2含量存在明显的下降过程,即从早期约661ppm(1ppm=1μLL.1)降低到晚期约565ppm.上述结果与GEOCARBⅡ基本吻合,表明三冬期CO2含量远高于现代.相对高的CO2水平为这一时期气候的温暖性提供了新的证据.此外,植物数据显示,白垩纪CO2含量总体上呈现出下降的趋势,但在不同时期存在不同幅度的波动,并以赛诺曼晚期、土伦期、三冬早期、坎潘晚期和/或马斯特里赫特晚期最为明显.对古植物数据的综合分析表明,晚白垩世全球陆表均温亦存在多次波动.全球陆表均温的增量(ΔT)在赛诺曼早期约为3℃,土伦中期增至4.7℃,而随后又在柯尼亚克中期迅速降低至2.2℃.自三冬期以后,全球陆表均温逐渐降低,并伴有一些小幅波动.
Quantitative reconstruction of Cretaceous atmospheric CO 2 content based on marine and terrestrial records is particularly important for understanding the “greenhouse conditions” of this period, but there are still very limited pale-plant data at various stages. Based on stomatal index techniques, According to the fossil epidermis of three layers of the genus Mycelium in Yong’an Village, Jiayin, Heilongjiang, the atmospheric CO2 content was reconstructed in the three winter months of the Late Cretaceous.The results of regression analysis showed that there was a significant decrease in the CO2 content in the three winters from In the early stage, about 661ppm (1ppm = 1μLL.1) was reduced to about 565ppm in the late stage.The above results are basically consistent with GEOCARBⅡ, indicating that the content of CO2 in the three winters is much higher than that in modern times.The relatively high CO2 level provides a new In addition, the plant data show that the Cretaceous CO2 content in general showed a downward trend, but at different times there are different amplitude fluctuations, and the late Norfolk, Toulon period, Early winter, early Campanian and / Or Maastricht late most obvious.The comprehensive analysis of palaeoclimate data show that the Late Cretaceous global land surface temperature also exists multiple fluctuations.The global land surface temperature increase (ΔT) Period is about 3 ℃, the mid-Toulon increased to 4.7 ℃, and then quickly lowered to 2.2 ℃ in the mid-Coyne Ark. Since three winter period, the global land surface average temperature is gradually reduced, and accompanied by some minor fluctuations.