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

我的研究计划的目标是开发和应用创新的同位素年代学策略来研究景观对气候和构造强迫的响应。我们试图提高我们对上新世(5.3至2.6万年前)北极地貌对气候变化的戏剧性大规模响应的理解。全球气候变暖导致反馈(例如，冰的反照率)导致北极年平均气温(&gt；10°)上升，并改变了降水模式，使森林(包括铁杉)得以扩展到埃尔斯米尔岛。在那里，像骆驼一样多样的动物进化而来。河流侵蚀和携带了来自东部和次北极地区的沉积物，并形成了一个向西增厚的沉积物楔形，从育空延伸到湄公河1200公里，填满了岛间航道，并达到了离岸3公里的厚度。气候变冷，海平面随着冰川作用而下降，波弗特组的切割再次隔离了岛屿，海峡-辐射器系统恢复了。尽管这个上新世实验产生了深远的影响，但令人惊讶的是，我们对所需的条件和所涉及的过程的速度知之甚少。通过创新的方法，我们的研究解决了关于这些景观反应的触发因素和速度的问题并测试了假设。目前与温度、时间序列或特定过程无关的上新世古环境记录的新年龄估计将有助于区分古环境和森林记录的空间差异和时间差异。对时间、持续时间和沉积物通量速率的估计，以及改进的表面图和与近海(Iperk组)成分的相关性，将有助于我们检验有关全球和区域气候、构造、均衡和海洋学力量的作用的假设。考虑到在沉积物可获得性对永久冻土融化敏感的北极地区，沉积物快速再动员的潜力很大，本世纪预计的2摄氏度全球变暖是否会重新引发如此重大的景观反应？对北极基础设施、水质和港口发展的影响有多大？这一结果还将对波弗特海和加拿大盆地用于油气评价的沉积物模型产生直接影响。

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.