Full-glacial paleosols in perennially frozen loess sequences, Klondike goldfields, Yukon Territory, Canada
Full-glacial paleosols in perennially frozen loess sequences, Klondike goldfields, Yukon Territory, Canada
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加拿大育空地区克朗代克金矿区常年冻结的黄土序列中的全冰川古土壤
DOI：
10.1016/j.yqres.2006.02.008
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发表时间：
2006
影响因子：
2.3
通讯作者：
J. Westgate
中科院分区：
文献类型：
--
作者：
Paul T. Sanborn;C.A. Scott Smith;D. Froese;G. Zazula;J. Westgate
Klondike金矿多年冻结黄土沉积包括全冰期环境下形成的古土壤，并与海洋同位素阶段（MIS） 2和4相对应。有机和无机碳和粘土的分布模式、微观结构和剖面形态表明，土壤的形成发生在一个富碱性的环境中，有机质主要以根碎屑的形式增加。在距离约20 km的位置，与MIS 4相关的黄土-古土壤序列中冰冻扰动和冰楔发育的表达强度向上减弱，表明干旱程度增加。低温扰动特征和冰楔融化不整合的配置，大量地松鼠洞穴的存在，以及泥炭堆积的缺乏表明，这些基质主要是排水良好的，与育空中西部类似地点的现代土壤相比，具有相同或更厚的活动层。这些古土壤的某些特征与现代草原和冻土带土壤相似，与东白令陆桥全冰期当地生态多样性的植物大化石证据一致。
Perennially frozen loess deposits in the Klondike goldfields include paleosols formed in full-glacial environments, correlated by Alaskan distal tephra with Marine Isotope Stages (MIS) 2 and 4. Patterns of organic and inorganic carbon and clay distribution, microstructures, and profile morphologies indicate that soil formation occurred in a base-rich environment in which organic matter accreted predominantly as root detritus. At sites approximately 20 km apart, the expression of cryoturbation and ice wedge development decreases in strength upward in loess–paleosol sequences correlated with MIS 4, suggesting increasing aridity. Configurations of cryoturbation features and ice-wedge thaw unconformities, the presence of numerous ground squirrel burrows, and an absence of peat accumulation suggest that these substrates were predominantly well-drained, with active layers of equal or greater thickness than in modern soils on similar sites in the west-central Yukon. Some characteristics of these paleosols are similar to those of modern steppe and tundra soils, consistent with plant macrofossil evidence for local ecological diversity during full-glacial conditions in eastern Beringia.