Collaborative Research: Rates of Long-Term Vegetation and Climate Change in North America and Europe

对北美东部化石-花粉数据变化率的分析表明，许多遗址在10,000-13,000年前最后一次冰川消融期间和过去1000年期间经历了重大变化。PIS建议将先前的研究扩展到北半球的几个新区域，并确定过去18,000年来北美西北部和东部气候和植被变化的时间、规模和地理模式。他们还将使用欧洲的一个平行数据库来研究过去18,000年来欧洲的模式和变化速度，以便与北美进行比较。通过使用北美和欧洲的花粉数据库，这项研究将确定北半球周围宽带内快速植被变化的同步程度，从而确定大气环流重大快速变化的可能时间。此外，还将特别关注一个关键地点，佛罗里达州的杜兰湖，它拥有至少45,000年前的连续高分辨率花粉地层学。杜兰湖的花粉地层显示出重大的、突然的变化，这可能与25,000-55,000年前格陵兰Dye 3冰芯中尚不清楚的同位素波动有关。研究结果将为过去20,000年来全球变化的性质和程度提供非常重要的数据。

Analyses of rates of change in fossil-pollen data from eastern North America reveal that many sites experienced major changes 10,000-13,000 years ago during the last deglaciation and again during the last 1000 years. The PIs propose to expand previous research to several new regions of the northern hemisphere, and to determine the timing, magnitude, and geographic patterns of changes in climate and vegetation during the past 18,000 years in northwestern as well as eastern North America. They will also use a parallel database in Europe to study the patterns and rates of change in Europe over the last 18,000 years, for comparison with North America. Through use of pollen databases for North America and Europe, this research will establish the degree to which rapid vegetation changes in a broad band around the northern hemisphere are synchronous, and will thus identify probable times of major rapid changes in atmospheric circulation. In addition, special attention will be given to a critical site, Lake Tulane, Florida which has a continuous high-resolution pollen stratigraphy extending to at least 45,000 years ago. The pollen stratigraphy from Lake Tulane exhibits major, abrupt changes, which may correlate with as yet poorly understood isotope fluctuations in the Dye 3 Greenland ice core during the period 25,000-55,000 years ago. The results of the research will provide very important data on the nature and extent of global change in the last 20,000 years.