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在白垩纪温室世界内的超温暖条件下，大约9000万年前的远足。在高北极的地质中发现了高温和异常二氧化碳火山释气的证据。前者以在阿克塞尔海伯格岛发现的脊椎动物化石的壮观组合的形式出现，包括体型庞大的鳄鱼状鳄龙、海龟和鱼类。后者是由大陆溢流玄武岩和阿尔法-门捷列夫洋脊的存在推断的;这些特征可能形成地球上最庞大的大火成岩省之一。研究人员建议在高北极地区进行多学科研究，以提高对与脊椎动物化石相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（放射性年龄和古地磁分析）的理解。有了这些数据，研究人员将测试先前的解释，即在没有季节性冰的情况下，年平均温度较高，以及同期火山活动的脉冲是否可能通过改变大气二氧化碳而导致推断的变暖。建议的工作将有助于至少一个博士学位。论文，并将涉及谁将在高北极地区和实验室接受实地培训的本科生。研究人员还建议开展外联工作，包括与当地K-12学校合作，以及利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.