Early neoproterozoic evolution of the Amundsen Basin

阿蒙森盆地新元古代早期演化

• 批准号: 205040-2010
• 负责人: Rainbird, Robert
• 金额: $ 1.09万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=593887
• 关键词: Early; neoproterozoic; evolution; Amundsen; Basin

The proposed research will investigate a 4 km-thick succession of sedimentary rocks known as the Shaler Supergroup that are well-exposed on northwestern Victoria Island, Northwest Territories. The precursor sediments were deposited in the Amundsen sedimentary basin nearly 1 billion years ago. The basin was situated within an ancient supercontinent, Rodinia, and records Earth's environmental history from the time of supercontinent amalgamation until its break-up about 250 million years later. The proposed detailed sedimentological, stratigraphic and geochemical studies will build upon previous research, leading to a greater understanding of larger-scale tectonic, geochemical and biological evolution during a poorly understood period of Earth's history. Questions that will be addressed include: 1) was the Amundsen basin part of a larger basin that was intermittently open to an exterior ocean? If the Shaler Supergroup represents deposition in a large basin within Rodinia, where are the correlative sedimentary strata from the other side of the basin that were separated when Rodinia broke apart? Such information, combined with that from parallel studies, will help us to reconstruct Rodinia. 2) What was the mechanism of subsidence in these interior basins and how does one explain the intermittent cycles of basin restriction and open ocean conditions that are observed? Further, what was the duration and mechanism of this cyclicity? 3) What was the ancient geography of north-western Canada at this time and how does that fit with paleogeographic models proposed for similar-age rocks on other continents (e.g. Australia, Siberia)?

拟议的研究将调查一个4公里厚的沉积岩系列，称为谢勒超群，在西北地区维多利亚岛西北部暴露良好。这些前体沉积物是在近10亿年前沉积在阿蒙森沉积盆地的。该盆地位于一个古老的超大陆Rodinia，并记录了地球从超大陆合并到大约2.5亿年后解体的环境历史。拟议的详细沉积学、地层学和地球化学研究将建立在以前的研究基础上，从而更好地了解地球历史上一个知之甚少的时期的大规模构造、地球化学和生物演变。将解决的问题包括：1）阿蒙森盆地是一个更大的盆地的一部分，间歇性地开放到外部海洋？如果谢勒超群代表Rodinia内一个大盆地的沉积，那么Rodinia分裂时从盆地另一侧分离出来的相关沉积地层在哪里？这些信息，结合来自平行研究的信息，将有助于我们重建Rodinia。2)这些内陆盆地的沉降机制是什么？如何解释所观察到的盆地限制和开阔海洋条件的间歇性循环？此外，这种周期性的持续时间和机制是什么？3)此时加拿大西北部的古代地理状况如何？这与针对其他大陆（例如澳大利亚、西伯利亚）类似年龄岩石提出的古地理模型如何相符？