浙东新近纪一种栎属植物化石微细特征及其古环境指示

归于壳斗科栎属的一种植物化石黄毛青冈(亲缘种)Quercusaff.delavayi Franch采于浙江天台中新统下南山组。该化石不仅具有与现生黄毛青冈Quercus delavayi Franch相似的叶形态结构,而且两者表皮微细构造亦颇为一致,宏观和微观特征表明,当前材料与现生黄毛青冈具有一定的亲缘关系。通过研究不同时间、不同地点现生黄毛青冈的表皮微细特征,发现黄毛青冈毛基的个体发育重演了青冈亚属毛基的系统演化。进一步比较化石与现生材料的毛基参数及其他表皮特征,推论浙江天台中新世的古气候较现在温暖湿润,根据现生与化石黄毛青冈气孔比率计算出浙江天台中新世古大气CO2体积分数为(395.22±5.61)×10-6。

Microstructures of one species of Quercus from the Neogene in Eastern Zhejiang and its palaeoenvironmental indication

The fossil Quercus aff.delavayi Franch was collected from the Xiananshan Formation of the Miocene in Tiantai,Zhejiang Province,which is the same as extant Quercus delavayi Franch not only in the leaf architecture,but also in the epidermal characteristics.Macro-and micro-characteristics show that present fossil material is related to extant Q.delavayi.By comparing microstructure of extant Q.delavayi growing in different regions and different years,it is found that the ontogeny of trichome base of Q.delavayi is a recapitulation to the phylogenetic development of trichome base of the subgenus Cyclobalanopsis.The comparison of cuticular characteristics between fossil and extant Q.delavayi based on the principle of the Nearest Living Relative species suggests that(1) atmospheric CO2 concentration in Miocene was about 395.22±5.61ppmv;and that(2) the Miocene climate of Tiantai,Zhejiang was warmer and more humid than today.