Analysis of a Late Cretaceous Vertebrate Fauna, North Slope,Alaska

在北美和亚洲中纬度地区出现的密切相关的陆生脊椎动物表明，在白垩纪晚期，阿拉斯加是陆地传播的洲际路线的一部分，并支持了多种动物。直到最近，这些动物群的组成才为人所知。在阿拉斯加北坡发现的集中的恐龙化石为首次评估白垩纪动物群的组成提供了可能。在这个地区进行实地工作，可以对北坡地区保存的脊椎动物动物群进行彻底的取样。美国地质调查局的成员正在研究这个地质剖面的无脊椎古生物学、古植物学、年代学和磁地层学。将这些和其他调查联系起来，这些事件应该能提供一些恐龙对极端温度和光照条件的耐受性的信息。目前大多数关于恐龙灭绝的假设，要么是灾难性的，要么是渐进的环境变化。确定阿拉斯加恐龙可能的环境耐受范围将有助于对这些假设的评估。

Occurrences of closely related, terrestrial vertebrates at mid- latitudes in North America and Asia suggest that Alaska was part of an intercontinental route of overland dispersal and supported diverse faunas during the late Cretaceous. Until recently the composition of these faunas was unknown. Discovery of concentrations of dinosaur fossils on the Alaskan North Slope opens the possibility for the first assessment of the composition of this Cretaceous fauna. Field work in this area will allow thorough sampling of the vertebrate fauna preserved in North Slope localities. Members of the U.S. Geological Survey are investigating the invertebrate paleontology, paleobotany, tephrachronology, and magnetostratigraphy of this geological section. Correlated with these and other lines of investigation, the occurrences should yield information on the tolerances of some dinosaurs to extremes in temperature and light conditions. Most current hypotheses concerning dinosaurian extinction invoke either catastrophic or gradual environmental change as a causal factor. Determination of the probable ranges of environmental tolerance of Alaskan dinosaurs will contribute to the evaluation of these hypotheses.