Eocene Floras of the Northern Hemisphere: Paleoclimate and Implications for Large Scale Floristic Interchange

北半球始新世植物群：摘要本文将通过与德国和中国的同事合作，对北美、欧洲和亚洲中纬度地区早始新世和中始新世植物区系进行详细的第一手比较，以评估气候比今天更温暖时期的植物地理格局，以及高纬度大陆间植物区系交换的可能性。PI将比较北美洲（美国西部的West Branch Creek和Green River）、西欧（德国的Messel和Eckfeld）和东亚（中国的抚顺和华甸）早始新世和中始新世湖泊沉积物中保存的巨型化石区系。通过对相关的哺乳动物群和/或放射性测定的火山灰进行对比，确定了这些组合的年龄。每个站点的古气候将基于叶面地貌分析进行比较，以给出年平均温度和降水的近似值。在始新世早期和中期，将进行洲际间和洲际间的植物区系比较，以确定每对大陆间共有和特有分类群的相对比例。由此产生的观测结果将：1)提供这些广泛分离的湖盆的年平均温度和降水的近似值；2)表明始新世早期和中期不同洲际传播途径的相对重要性；3)便于比较早第三纪时期植物和哺乳动物的传播模式。

Eocene floras of the Northern Hemisphere: paleoclimate and implications for large scale floristic interchangeStephen ManchesterEAR-0087780AbstractDetailed first-hand comparisons will be made between selected early and middle Eocene floras of mid-latitude North America, Europe and Asia through collaboration with colleagues in Germany and China as a means of assessing phytogeographic patterns during a time when the climate was warmer than today, and there was potential for high-latitude floristic exchange between continents. PI will compare megafossil floras preserved in the sediments of early and middle Eocene lakes from North America (West Branch Creek and Green River floras, western US), western Europe (Messel and Eckfeld, Germany), and Eastern Asia (Fushun and Huadian, China). The ages of each these assemblages are established through correlations of associated mammal faunas and/or radiometrically dated volcanic ashes. Paleoclimate of each of the sites will be compared based on foliar physiognomic analyses to give approximations of mean annual temperature and precipitation. Intra- and intercontinental floristic comparisons will be made to determine the relative proportion of shared vs. endemic taxa between each pair of continents in the early and middle Eocene. The resulting observations will: 1) provide approximations of the mean annual temperature and precipitation of these widely separated lake basins, 2) indicate the relative importance of different routes of intercontinental dispersal in the early and middle Eocene, and 3) facilitate comparison of dispersal patterns in plants with those observed in mammals during the early Tertiary.