Analysis of the short period climatic change by pyrolysis TMAH methylation GC-MS

摘要描述了加利福尼亚近海沉积物（ODP Leg 167, Site 117E）的古环境分析结果，特别是使用木质素指数。木质素总浓度（V：香草基+ S：丁香基+ C：肉桂基）在冰期（更新世）较高（平均为960 μg/g-C），变化较大（500 ~ 1800 μg/g-C），而在全新世则稳定在较低的平均值（400 μg/g-C）。在冰期，香草基和丁香基浓度的变化与总木质素的变化相似，但在全新世变化不大。此外，由于S/V比值从约15ka前开始逐渐增加，这一结果清楚地表明被子植物的贡献在全新世变得主要。由于Heusser（1998）在该海域其他沉积物中发现被子植物（栎和灌木林）的花粉相对于23 ka前减少，裸子植物（松和杜松）的花粉相对于15 ka前减少，我们的结果与Heusser（1998）的结果一致。肉桂基（Pc：对香豆酸和Vc：阿魏酸）在冰期浓度高，在全新世浓度低，与其他木质素相似。由于整个年龄Pc/Vc的比值都在1.0以上，该比值大于Goni and Hedges（1992）对草本植物的比值（0.94）。从这一结果来看，高Pc/Vc比值可能是由其他具有高Pc/Vc比值的来源造成的。在此基础上，采用TMAH方法对两种松树的6种花粉进行了分析。因此，松树的Pc/Vc比值大于18，因为松树尤其富含Pc。结果表明，Pc/Vc比值较高的冰期（~ 10 ka前）受松木花粉的影响。

This abstract report describes the analytical result of the paleo-environment from the sediment of the offshore of California (ODP Leg 167, Site 117E), especially with using the idex of lignin.While the total concentration (V : vanillyl + S : siringyl + C : cinnamyl) of lignin is high (an average of 960 μg/g-C) with large variation (500-1800 μg/g-C) in the glacial age (Pleistocene), it is stable low average of 400 μg/g-C) in the Holocene. The both concentrations of vanillyl and syringyl are largely changed similar with total lignin at the glacial age, and they are changed little at the Holocene. Moreover, since the S/V ratio increases gradually from about 15 ka ago, this result shows clearly that contribution of angiosperm becomes largely at the Holocene. Since Heusser (1998) shows that the pollens of angiosperms (oak and chaparral) decrease relatively from 23 ka ago and those of gymnosperms (pine and juniper) decrease relatively from 15 ka ago in other sediment of this sea area, our results is consistent with the results of Heusser (1998).The concentration of cinnamyl (Pc : p-coumaric acid and Vc : ferulic acid) is high at the glacial age, and is low at the Holocene similar with other lignin. Since the ratio of Pc/Vc is over 1.0 all over the age, the ratio is larger than the ratio (0.94) of herbaceous plant by Goni and Hedges (1992). From this result, the high Pc/Vc ratio suggests to be contributed from other source having high Pc/Vc ratio. Then, we analyzed six pollens including two species of pines by the TMAH method. Consequently, the Pc/Vc ratios of pines are found to be over 18, because they are rich in Pc, especially. This result suggests that the glacial age (〜10 ka ago) with high Pc/Vc ratio is affected by the pollens of pines.