The ultra-warm Arctic ca. 90 million years ago

超温暖的北极大约。

• 批准号: 1107801
• 负责人: John Tarduno
• 金额: $ 92.53万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1107801&HistoricalAwards=false
• 关键词: ultra; warm; Arctic; ca.; 90

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.

北极地区的地质历史记录了过去的气候条件，可以为了解现代条件和未来变化的可能性提供线索。这项工作的重点是在大约9000万年前的白垩纪温室世界的超温暖条件下进行短途旅行。在北极高地的地质中发现了高温和异常二氧化碳火山喷发的证据。前者以在阿克塞尔海伯格岛上发现的一组壮观的脊椎动物化石的形式出现，包括大型鳄鱼状的冠军龙、海龟和鱼类。后者是由大陆洪水玄武岩和阿尔法-门捷列夫洋脊的存在推断出来的；这些特征可能形成地球上面积最大的大型火成岩省之一。研究人员建议在高北极地区进行多学科研究，以提高对脊椎动物化石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）的理解。有了这些数据，研究人员将测试先前的解释，即没有季节性冰的高平均年气温，以及同期火山活动的脉冲是否可能通过改变大气中的二氧化碳来促进推断的变暖。提出的工作将有助于至少一篇博士论文，并将涉及本科生，他们将在北极高地和实验室接受实地培训。调查人员还建议开展外联工作，包括与当地K-12学校合作，并利用新媒体向公众传播他们的研究结果。