Reconstruction of altitudinal transportation range of leaves based on stomatal evidence: An example of the Early Pleistocene Fagus leaf fossils from central Japan
Reconstruction of altitudinal transportation range of leaves based on stomatal evidence: An example of the Early Pleistocene Fagus leaf fossils from central Japan
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DOI：
10.1016/j.palaeo.2018.06.011
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发表时间：
2018-09
期刊：
影响因子：
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通讯作者：
Yuqing Wang;Ayano Ito;Y. Huang;T. Fukushima;N. Wakamatsu;A. Momohara
中科院分区：
文献类型：
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作者：
Yuqing Wang;Ayano Ito;Y. Huang;T. Fukushima;N. Wakamatsu;A. Momohara
化石植物组合在古环境估算中起着至关重要的作用，特别是对新生代而言。然而，化石组合反映源森林的程度难以估计。现代组合与亚化石组合的对比显示出显著差异，表明植物器官的运输会影响古环境分析的准确性。本研究基于30片沙山组（1.54-1.66 Ma）油豆叶化石的气孔频率（气孔指数和气孔密度）变化，对叶片输运进行了研究。利用波动指数来区分古叶的阳光和阴影形态，并计算了仅太阳古叶的气孔频率变化。考虑柴叶化石气孔指数的变化，估算1.54 Ma ~ 1.66 Ma暖期古pco2的变化约为35.0 ~ 39.6 pa。基于这一古co2变化，估计了早更新世油桐化石的海拔迁移范围在1000 m以上。我们推测，在早更新世时期，化石组合可能来自化石地点附近的广泛海拔高度。这为植物沉积前的纵向迁移提供了一个例子，为从化石组合中重建古植被和古气候提供了一个考虑因素。
Fossil plant assemblages play a critical role in paleoenvironment estimation, especially for the Cenozoic. However, the extent that the fossil assemblage reflects the source forest is difficult to estimate. The comparison between modern assemblages and their subfossil assemblages shows a significant difference, indicating that the transportation of plant organs can affect the accuracy of paleoenvironment analysis. In this study, we aim to detect leaf transport based on stomatal frequency (stomatal index and stomatal density) variation of 30 fossilizedFagus crenataleaves from the Sayama Formation (1.54–1.66 Ma). We distinguished the sun and shade morphotype of fossil leaves by using undulation index and calculated stomatal frequency variation of only sun fossil leaves. Considering the stomatal index variation of fossilFagus crenataleaves, the paleo-pCO2variation in a warm period between 1.54 Ma and 1.66 Ma was estimated as ca. 35.0 to 39.6 pa. Based on this paleo-pCO2variation, altitudinal transportation range of the Early Pleistocene fossilFagus crenataleaves was estimated at over 1000 m. We presume that leaves ofFagus crenatain the fossil assemblage possibly had come from a wide range of altitudes near the fossil site during the Early Pleistocene. This provides an example of altitudinal transportation of plants before their deposition, which suggests a consideration when reconstructing the palaeovegetation and palaeoclimate from fossil assemblages.