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

北半球始新世植物群：古气候和大规模植物区系交换的意义斯蒂芬·曼斯特EAR-0087780摘要通过与德国和中国的同事合作，我们将对北美、欧洲和亚洲中纬度地区选定的始新世早期和中期植物群进行详细的第一手比较，作为一种手段，在气候比今天温暖的时候评估植物地理格局，大陆之间有可能进行高纬度植物区系交流。Pi将比较北美(美国西部的West Branch Creek和Green River植物群)、西欧(梅塞尔和埃克菲尔德，德国)和东亚(抚顺和桦甸，中国)始新世早期和中期湖泊沉积物中保存的巨型植物群。每个组合的年龄是通过相关哺乳动物动物群和/或放射性年代测定火山灰的对比来确定的。每个地点的古气候将根据叶地貌分析进行比较，以得出年平均温度和降雨量的近似值。将进行洲内和洲际植物区系比较，以确定在始新世早期和中期，每对大陆之间共享的与特有的类群的相对比例。由此产生的观察结果将：1)提供这些相距遥远的湖盆的年平均温度和降水量的近似值，2)表明在始新世早期和中期不同洲际扩散途径的相对重要性，以及3)有助于比较植物和哺乳动物在早第三纪观察到的扩散模式。

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.