Understanding Jurassic and Cretaceous High Arctic Paleoenvironmental and Paleoclimate Change

作为地球气候系统的重要组成部分，了解加拿大北极地区的古环境和古气候演变，是评估侏罗纪和白垩纪时期短期和长期气候、环境和古地理变化的基础。我们在2011年和2014年的北极勘探季取得了巨大的成功；在加拿大高北极Sverdrup盆地3.5 km厚的沉积序列中首次记录了主要的白垩纪古海洋学和古气候事件（如海洋缺氧事件（oae）、晚Aptian寒流）。我们的研究结果表明，在白垩纪关键时期对露头地层剖面进行描述、取样和研究，在短期和长期时间尺度上破译海洋古环境和古气候事件和动力学具有巨大的潜力和可行性。本项目拟以白垩纪高北极Sverdrup盆地有机碳埋藏增强对Toarcian OAE、早期Aptian OAE 1a和晚期Cenomanian OAE 2等全球碳循环气候扰动的影响为例进行评估。我们打算评估碳埋藏的动态及其相关的古海洋和古气候后果。我们之前的研究似乎表明，白垩纪高北冰洋作为具有全球意义的碳汇起着重要作用。我们建议验证这一假设，并量化白垩纪高北冰洋碳埋藏的全球影响。此外，我们的国际研究团队将把重点放在侏罗纪到早白垩世大约60万年的长期气候发展上（Savik, Awingak， Deer Bay到下Isachsen组和晚白垩世Kanguk组），并在晚白垩世的年代地层框架内校准北极硅藻和硅藻的发展记录。后者将阐明在早期硅藻演化记录中，在南极洲威德尔海保存异常完好的中Albian硅藻和有充分记录的Campanian/Maastrichtian硅藻丰富矿床之间，存在一个长期存在的黑暗间隔。

Understanding the paleoenvironmental and paleoclimatic evolution of Canada’s Arctic region, as a crucial component of Earth’s climate system, is fundamental to assess short- and long-term climate, environmental, and paleogeographic changes during Jurassic and Cretaceous time. Our 2011 and 2014 Arctic field seasons were tremendously successful; we documented for the first time major Cretaceous paleoceanographic and paleoclimatic events (e.g. Oceanic Anoxic Events (OAEs), late Aptian cold snap) in a 3.5 km-thick sedimentary succession of the Canadian High Arctic Sverdrup Basin. Our results indicate the great potential and feasibility to describe, sample and study outcropping stratigraphic sections to decipher on short- and long-term timescales marine paleoenvironmental and paleoclimate events and dynamics during critical times of the Cretaceous. This project proposes to assess the impact of enhanced organic carbon burial in the Cretaceous High Arctic Sverdrup Basin on global climate perturbations of the carbon cycle such as the Toarcian OAE, the early Aptian OAE 1a and the late Cenomanian OAE 2 as case studies. We intent to evaluate the dynamics of carbon burial and their associated paleoceanographic and paleoclimate consequences. Our previous investigation seems to suggest that the Cretaceous High Arctic Ocean plays an important role as carbon sink of global significance. We propose to test this hypothesis and quantify the global impact of carbon burial in the Cretaceous High Arctic Ocean. In addition, our international research team will extent the focus on Jurassic to early Cretaceous long-term climate development over a period of approximately 60 m.y. (Savik, Awingak, Deer Bay to lower Isachsen formations and late Cretaceous Kanguk Formation) and calibrate the developing record of Arctic diatom and silicoflagellate evolution within a chronostratigraphic framework of the late Cretaceous. The latter will illuminate a long-standing dark interval in the early record of diatom evolution between the exceptionally well-preserved middle Albian diatoms from the Weddell Sea of Antarctica and the well documented Campanian/Maastrichtian diatom rich deposits.