The ultra-warm Arctic ca. 90 million years ago

北极地区的地质历史记录了过去的气候条件，可以提供对现代条件和未来变化潜力的洞察。这项拟议工作的重点是白垩纪温室世界内的一次短途旅行，大约在9000万年前，达到了超温条件。在北极高地的地质中发现了高温和异常二氧化碳火山放气的证据。前者的形式是在阿克塞尔·海贝格岛上发现的一组壮观的脊椎动物化石，包括大型鳄鱼状冠军龙、海龟和鱼。后者是由大陆泛滥玄武岩和阿尔法-门捷列夫洋脊的存在而推断的；这些特征可能形成地球上面积最大的火成岩大省之一。研究人员建议在北极高地进行多学科研究，以增进对与脊椎动物化石有关的绝对年龄和古温度(碳和氧同位素分析)以及异常火山活动的绝对年龄和持续时间(辐射年龄和古地磁分析)的了解。有了这些数据，研究人员将检验之前的解释，即没有季节性冰的年平均温度较高，以及同期火山活动的脉冲是否通过改变大气二氧化碳而导致推断的变暖。拟议的工作将有助于至少一篇博士论文，并将涉及将在北极高地和实验室接受实地培训的本科生。调查人员还建议开展外联工作，包括与当地K-12学校合作，并使用新媒体向公众传播他们的研究结果。

The geologic history of the Arctic region records past climatic conditions that can provide insight into modern conditions and the potential for future change. The focus of this proposed work is on an excursion within the Cretaceous greenhouse world to ultra-warm conditions, approximately 90 million years ago. Evidence for both high temperature and anomalous CO2 volcanic outgassing is found in the geology of the High Arctic. The former comes in the form of a spectacular assemblage of vertebrate fossils found on Axel Heiberg Island, including large-bodied crocodile-like champsosaurs, turtles and fish. The latter is inferred by the presence of continental flood basalts and the Alpha-Mendeleev Oceanic Ridge; these features may form one of Earth's most voluminous large igneous provinces. The investigators propose multidisciplinary studies in the High Arctic to improve understanding of the absolute age and paleotemperatures associated with the vertebrate fossils (carbon and oxygen isotope analyses) and the absolute age and duration of the anomalous volcanism (radiometric age and paleomagnetic analyses). With these data, the investigators will test prior interpretations calling for high mean annual temperatures without seasonal ice, and whether contemporaneous pulses of volcanic activity could have contributed to the inferred warming by altering atmospheric CO2. The work proposed will contribute to at least one Ph.D. thesis and will involve undergraduates who will receive field training in the High Arctic and in the laboratory. The investigators also propose outreach efforts including collaboration with local K-12 schools and the use of new media to disseminate results of their study to the general public.