Precise reconstruction of variation in paleovegetation during Cretaceous hot period by analyses of terrestrial plant-derived organic molecules in sediments

通过对日本北海道白垩纪叶佐群沉积岩中陆生植物源生物标志物和干酪根的分析，重建古植被和陆生古环境的长时间尺度变化。特别是，我们发现快速变化的被子植物/裸子植物植被比例和针叶植被的陆生植物萜类生物标志物的分析评估。此外，我们认为干酪根中抗性大分子释放的长链正烷醇组成可以作为落叶阔叶植物植被的指示剂。在古植被的变化，使用长链的正烷醇从干酪根释放几乎是同步的，在被子植物/裸子植物植被使用陆生植物生物标志物，证实了高适用性的释放的正烷醇替代重建古植被从古沉积物。

The objective of this study is to reconstruct long time scale variations in paleovegetation and terrestrial paleoenvironment by analyses of terrestrial plant-derived biomarkers and kerogens in sedimentary rocks from the Cretaceous Yezo Group, Hokkaido, Japan. In particular, we found rapid changes in angiosperm / gymnosperm vegetation ratio and coniferous vegetation evaluated by analysis of terrestrial plant terpenoid biomarkers. Moreover, we suggest that composition of long chain n-alkanols released from resistant macromolecule in kerogen can be useful as an indicator of deciduous broad leaf plant vegetation. Variation in the paleovegetation using the long chain n-alkanols released from kerogen is almost synchronous to that in angiosperm / gymnosperm vegetation using terrestrial plant biomarkers, confirming high applicability of the released n-alkanol proxy for reconstructing paleovegetation from ancient sediment.