Paleoclimate and Paleoecology in High Latitude, Terrestrial Vertebrate Communities from the Early-Middle Eocene of Ellesmere Island, Nunavut, Arctic Canada

加拿大北极地区努勒维特埃尔斯米尔岛早中始新世高纬度陆生脊椎动物群落的古气候和古生态

• 批准号: 0454906
• 负责人: Jaelyn Eberle
• 金额: --
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-15 至 2008-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0454906&HistoricalAwards=false
• 关键词: Paleoclimate; Paleoecology; Latitude; Terrestrial; Vertebrate

The Principal Investigators will test hypotheses concerning the Eocene global warm period and its effects on high-latitude terrestrial ecosystems by reconstructing paleoclimate and -ecology from d18O(PO4), d18O(CO3), and d13C values of biogenic phosphate in vertebrate tooth enamel from Early-Middle Eocene localities on Ellesmere Island, Canada (~79degrees N). Specifically, they will test the hypothesis that Eocene vertebrates inhabiting the High Arctic preferred temperatures and habitats similar to their living analogs and are therefore accurate paleoclimate and paleoecologic proxies. By comparison to published sea surface temperatures (SSTs), the Principal Investigators will test the hypothesis that quantitative climate changes in northern high-latitude terrestrial environments correlate to those determined for high-latitude open marine environments. The project will provide quantification of latitudinal gradients by determining d18O values of multiple vertebrate taxa (e.g., alligators, brontotheres, and tapirs) that co-occur in mid- and high-latitude North America. Quantitative climate estimates for Early - Middle Eocene localities on Ellesmere Island should also provide data critical to understanding the onset of the Cenozoic cooling trend, purported to have begun with during early Middle Eocene time. Comparison of the Eocene mammals, particularly the large herbivores, from Ellesmere Island with living relatives and analogues, combined with d13C analysis of the biogenic phosphate in their teeth, should provide insight into their habitat preferences (i.e., open habitat vs. closed canopy). Additionally, comparison of d13C values from the same genera coexisting at both mid- and high-latitudes (e.g., Coryphodon and the brontotheres Eotitanops and Palaeosyops) may illuminate important paleoecological differences that would otherwise not be evident in their morphology. Extensive paleontological field work in Eocene strata of the Eureka Sound Group on Ellesmere Island by the Principal Investigators provides paleoclimatic and paleoenvironmental estimates that are inferred from the fossil plants and animals, in addition to numerous specimens on which to conduct isotope analysesBroader Impacts: This project will result in the first comprehensive, quantitative paleoclimate data set from northern high-latitude terrestrial environments for the most significant global warming event in the last 65 million years (the Early Eocene), which is critical to understanding the impacts of future global warming on Earth's biota. The research will provide important high-latitude terrestrial data points for paleoclimate modelers concerned with Eocene climatic variability and latitudinal temperature gradients. This study will be the first to infer paleoecology of a high Arctic terrestrial vertebrate community on the basis of coupled carbon and oxygen isotope analyses (in conjunction with comparisons to mid-latitude taxa and modern analogs). The project will engage students, the general public (including the Inuit community), and scientists in a multidisciplinary, collaborative research alliance, and foster international and intercultural discourse. Results of the research will be broadly disseminated to scientific and lay audiences.

主要研究人员将通过重建古气候和生态学d18 O（PO 4），d18 O（CO 3）和d13 C值的生物源磷酸盐在脊椎动物牙釉质从早中始新世地点在加拿大埃尔斯米尔岛（~ 79度N）的高纬度陆地生态系统的影响，测试有关始新世全球暖期的假设。 具体来说，他们将测试的假设，始新世脊椎动物栖息在高北极喜欢的温度和栖息地类似于他们的生活类似物，因此是准确的古气候和古生态代理。 通过与公布的海面温度（SST）进行比较，主要研究人员将检验以下假设：北方高纬度陆地环境中的定量气候变化与高纬度开放海洋环境中确定的气候变化相关。 该项目将通过确定多个脊椎动物分类群的d18 O值（例如，短吻鳄、雷兽和貘），共同出现在中纬度和高纬度的北美。 对埃尔斯米尔岛始新世早中期地区的定量气候估计也应该为理解新生代冷却趋势的开始提供关键数据，据称该趋势始于始新世中早期。将来自埃尔斯米尔岛的始新世哺乳动物，特别是大型食草动物与现存亲属和类似物进行比较，结合对牙齿中生物源磷酸盐的d13 C分析，应该可以深入了解它们的栖息地偏好（即，开放栖息地与封闭树冠）。 此外，来自中纬度和高纬度共存的相同属的d13 C值的比较（例如，Coryphodon和brontotheres Eotanops和Palaeosyops）可能阐明了重要的古生态差异，否则在形态上不会很明显。首席调查员在埃尔斯米尔岛尤里卡湾群始新世地层中进行了广泛的古生物学野外工作，提供了根据植物和动物化石推断的古气候和古环境估计，此外还有许多标本可供进行同位素分析。该项目将产生第一个全面的，过去6500万年来最重要的全球变暖事件的北方高纬度陆地环境的定量古气候数据集（早始新世），这是了解未来全球变暖对地球生物群的影响至关重要。 这项研究将为研究始新世气候变化和纬度温度梯度的古气候建模者提供重要的高纬度陆地数据点。 这项研究将是第一个推断古生态学的北极陆地脊椎动物群落的基础上耦合的碳和氧同位素分析（结合比较中纬度类群和现代类似物）。 该项目将使学生、公众（包括因努伊特人社区）和科学家参与多学科合作研究联盟，并促进国际和文化间对话。 研究结果将广泛传播给科学界和非专业人士。