Development and application of cosmogenic nuclide methods to analyse Cenozoic landscape responses to climate and tectonic change

宇宙成因核素方法的开发和应用分析新生代景观对气候和构造变化的响应

• 批准号: 239961-2013
• 负责人: Gosse, John
• 金额: $ 2.91万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=634046
• 关键词: Development; application; cosmogenic; nuclide; methods

The goal of my research program is to develop and apply innovative isotope geochronology strategies to study landscape responses to climate and tectonic forcing. We seek to improve our understanding of a dramatic large-scale Arctic landscape response to climate change in the Pliocene (5.3 to 2.6 Myr ago). Warmer global climate led to feedbacks (e.g. ice albedo) that increased Arctic mean annual temperatures (>10°) and changed precipitation patterns to allow forests (including Hemlock) to expand to Ellesmere Is. where fauna as diverse as camels evolved. Streams eroded and carried sediment from eastern and sub-Arctic sources, and constructed a westward-thickening wedge of sediment that extended >1200 km from Yukon to Meighen Is., filled the inter-island channels, and reached thicknesses >3 km offshore. Climate cooled, sea level fell with glaciation, incision of the Beaufort Formation isolated the islands once again, and the channel-radiator system was restored. Despite the profound impact of this Pliocene experiment, it is surprising how little we know about the conditions required and the rates of processes involved. With innovative approaches our research addresses questions and tests hypotheses regarding the triggers and rates of these landscape responses. New age estimates for Pliocene paleoenvironmental records currently unlinked to temperature time series or specific processes will help distinguish spatial from temporal differences in the paleoenvironmental and forest records. Estimates of timing, durations, and sediment flux rates and improved surface maps and a correlation with offshore (Iperk Formation) components will help us test hypotheses regarding the roles of global and regional climatic, tectonic, isostatic, and oceanographic forces. Considering that the potential for rapid sediment remobilization is significant in the Arctic where sediment availability is sensitive to permafrost thawing, could such a significant landscape response be re-triggered by the projected 2°C global warming this century? To what degree of impact on Arctic infrastructure, water quality, and harbor development? The results will also have direct implications for sediment models used for hydrocarbon evaluation in Beaufort Sea and Canada Basin.

我的研究项目的目标是开发和应用创新的同位素地质年代学策略来研究景观对气候和构造强迫的响应。我们试图提高我们的理解一个戏剧性的大规模北极景观的气候变化在上新世（530万至260万年前）。全球气候变暖导致反馈（例如冰的融化），增加了北极的年平均温度（>10°），改变了降水模式，使森林（包括铁杉）扩展到埃尔斯米尔群岛。在那里进化出了像骆驼这样多种多样的动物河流侵蚀并携带了来自东部和亚北极地区的沉积物，形成了一个向西增厚的沉积物楔，从育空地区延伸到米恩群岛，长度超过1200公里，填充了岛间水道，离岸厚度超过3公里。气候变冷，海平面随着冰川作用而下降，博福特组的切割再次将岛屿隔离，水道-散热器系统得以恢复。尽管上新世的实验影响深远，但令人惊讶的是，我们对所需的条件和所涉及的过程的速率知之甚少。通过创新的方法，我们的研究解决了有关这些景观响应的触发器和速率的问题和测试假设。上新世古环境记录的新年龄估计目前与温度时间序列或特定过程无关，这将有助于区分古环境和森林记录的时空差异。对时间、持续时间和沉积物通量率的估计以及改进的地表地图以及与近海（伊珀克组）成分的相关性将帮助我们测试有关全球和区域气候、构造、均衡和海洋力作用的假设。考虑到北极沉积物的可利用性对永久冻土融化敏感，因此沉积物快速再流动的可能性很大，预计本世纪全球变暖2°C是否会再次引发如此重大的地貌反应？对北极基础设施、水质和港口发展的影响程度如何？研究结果对博福特海和加拿大海盆油气评价的沉积物模型也有直接影响。