Collaborative Research: Forty-Thousand Years of Yedoma: An investigation into the spatial heterogeneity and paleo-history of organic-rich permafrost in Alaska

NON-TECHNICAL ABSTRACT for Collaborative Research: Forty-Thousand Years of Yedoma (ARC 1107571) An investigation into the spatial heterogeneity and paleo-history of organic-rich permafrost in Alaska A new permafrost tunnel 4 m high and 30 m long was excavated near Fox, Alaska in 2011. It is adjacent to the older and widely known CRREL tunnel. The new tunnel penetrates yedoma (loess or silt) deposits ranging from modern to more than 40,000 years old. Beautifully exposed in the walls of the tunnel are a series of ice wedges, thermokarst-cave ice, and paleosols that record the climatic and ecological history of central Alaska since the last Ice Age. We propose to map and sample these sediments using a variety of analysis techniques, including extensive AMS radiocarbon dating to reveal environmental conditions during the yedoma formation. We will use the results to reconstruct the paleo-climatic and environmental history of the central Alaska region, a region that during the past 40,000 years has been cold enough to produce and support permafrost, but where now permafrost is thawing. The expected results will not only tell us about how climate has varied in Alaska during this critical period, but also in the other yedoma regions of the world which include Siberia and Canada. The new tunnel will be used as a classroom for students in geology and environmental engineering.

合作研究非专业摘要：“四万年来的耶多马冻土（yedoma，ARC 1107571）”
本研究旨在探究阿拉斯加地区富有机质多年冻土的空间异质性与古演化历史。2011年，研究团队在阿拉斯加州福克斯镇附近开挖了一座高4米、长30米的多年冻土隧道，该隧道毗邻历史悠久且广为人知的CRREL隧道。这座新隧道穿越了形成年代介于现代至4万年前、由黄土或粉砂构成的耶多马冻土（yedoma）沉积层。隧道壁上清晰裸露着一系列冰楔、热喀斯特洞穴冰与古土壤，这些地质体完整记录了末次冰期以来阿拉斯加中部的气候与生态演化历程。我们计划采用多种分析技术对该套沉积层进行测绘与采样，其中包括大量的加速器质谱放射性碳测年（AMS radiocarbon dating），以揭示耶多马冻土形成时期的古环境条件。我们将依托研究结果重建阿拉斯加中部地区的古气候与古环境演化历史：该区域在过去4万年间始终保持寒冷气候，足以形成并维持多年冻土，但如今其境内的多年冻土正逐步消融。本研究的预期成果不仅能够揭示这一关键时期阿拉斯加地区的气候变化规律，还可为全球其他分布有耶多马冻土的区域（包括西伯利亚与加拿大）提供科学借鉴。这座新建隧道还将作为地质与环境工程专业学生的实践课堂。