Collaborative Research: Effects of Climatic/Environmental Change on the Early Eocene Mammal Fauna of the Bighorn Basin, Wyoming

合作研究：气候/环境变化对Bighorn盆地早期始新世哺乳动物动物群的影响，WyomingKenneth D.Rose和Amy E.Chew，共同PIS为了了解气候/环境变化如何影响动物群进化，PIS将分析怀俄明州Bighorn盆地中部早始新世Willwood组哺乳动物动物群的变化。Bighorn盆地中部的哺乳动物化石记录是进行这项分析的理想材料，因为它密度大、研究广泛、连续分布，并与精细的气候/环境背景直接相关。该地区的威尔伍德组底部包括古新世/始新世最热事件(PETM)，这是全球变暖的一个短暂而突然的事件，与新生代哺乳动物历史上最戏剧性的周转事件之一有关。在这个序列中发现的另外两个较小的周转事件似乎对应于气候变化，但证据是模棱两可的。该项目和其他正在进行的工作应有助于澄清这些事件。这项研究的目标是收集跨越古新世/始新世界线和比格伦盆地中部早始新世第一个3My期间的高分辨率、密集采样的动物群变化记录，特别是针对采样不足的区段。这将使得能够从时间等间隔的连续样本进行比较，以评估物种周转的模式、丰度、多样性、相对身体大小以及始新世早期营养结构的变化。由此产生的动物群随时间变化的综合记录将被用来测试这些动物群变化与气候/环境变化之间的相关性。特别令人感兴趣的是，温度变化的幅度和方向以及降水的波动对动物群的影响。

Collaborative Research: Effects of Climatic/Environmental Change on Early Eocene Mammal Fauna of the Bighorn Basin, WyomingKenneth D. Rose and Amy E. Chew, co-PIsABSTRACT In order to understand how climatic/environmental change influences faunal evolution, the PIs will analyze changes in the mammalian faunas of the early Eocene Willwood Formation in the central part of the Bighorn Basin, Wyoming. The record of fossil mammals from the central Bighorn Basin is ideal for this analysis as it is dense, extensively studied, continuously distributed and directly associated with a fine-scale climatic/environmental context. The Willwood Formation in this area includes at its base the Paleocene/Eocene thermal maximum (PETM), a brief and abrupt episode of global warming, which is associated with one of the most dramatic turnover events in the history of Cenozoic mammals. Two other lesser turnover events recognized in this sequence appear to correspond to climatic shifts, but the evidence is equivocal. This project and other ongoing work should help to clarify these events. The goal of the study is to assemble a high-resolution, densely sampled record of faunal change across the Paleocene/Eocene boundary and during the first 3my of the early Eocene in the central Bighorn Basin, especially targeting under-sampled intervals. This will enable a comparison of successive samples from time-equal intervals, in order to evaluate patterns of species turnover, abundance, diversity, relative body size, and change in trophic structure during the early Eocene. The resulting comprehensive record of faunal change over time will be used to test the correlation between these faunal changes and climatic/environmental changes. Of particular interest will be the effect on faunas of variation in the magnitude and direction of shifting temperature and of fluctuation in precipitation.