Soil properties of western Wright Valley, Antarctica

Western Wright Valley, from Wright Upper Glacier to the western end of the Dais, can be divided into three broad geomorphic regions: the elevated Labyrinth, the narrow Dais which is connected to the Labyrinth, and the North and South forks which are bifurcated by the Dais. Soil associations of Typic Haplorthels/Haploturbels with ice-cemented permafrost at < 70 cm are most common in each of these geomorphic regions. Amongst the Haplo Great Groups are patches of Salic and Typic Anhyorthels with ice-cemented permafrost at > 70 cm. They are developed in situ in strongly weathered drift with very low surface boulder frequency and occur on the upper erosion surface of the Labyrinth and on the Dais. Typic Anhyorthels also occur at lower elevation on sinuous and patchy Wright Upper III drift within the forks. Salic Aquorthels exist only in the South Fork marginal to Don Juan Pond, whereas Salic Haplorthels occur in low areas of both South and North forks where any water table is > 50 cm. Most soils within the study area have an alkaline pH dominated by Na+ and Cl- ions. The low salt accumulation within Haplorthels/Haploturbels may be due to limited depth of soil development and possibly leaching.西赖特谷（Western Wright Valley）的范围从赖特上冰川（Wright Upper Glacier）延伸至戴斯（Dais）西端，可划分为三大地貌区：抬升的迷宫地貌区（Labyrinth）、与迷宫地貌区相连的狭长戴斯带，以及被戴斯带分隔的北支流与南支流。在上述三个地貌区中，以地下70cm以浅存在胶结冰永冻层为特征的典型简育寒冻土（Typic Haplorthels）/简育扰动寒冻土（Haploturbels）土壤组合最为常见。在简育土类（Haplo Great Groups）中，还分布有以地下70cm以深存在胶结冰永冻层为特征的盐化寒冻土（Salic）和典型旱生寒冻土（Typic Anhyorthels）斑块。此类土壤就地形成于风化程度极强、地表砾石占比极低的冰碛物中，分布于迷宫地貌区的上部侵蚀面以及戴斯带之上。典型旱生寒冻土（Typic Anhyorthels）还分布于支流区域内蜿蜒且呈斑块状分布的赖特上第三期冰碛物（Wright Upper III drift）的低海拔区域。盐化水成寒冻土（Salic Aquorthels）仅分布于南支流毗邻唐胡安池（Don Juan Pond）的区域，而盐化简育寒冻土（Salic Haplorthels）则见于南、北支流中地下水位高于50cm的低地。本研究区内的多数土壤呈碱性，其主要阳离子与阴离子分别为钠离子（Na+）与氯离子（Cl-）。简育寒冻土/扰动寒冻土（Haplorthels/Haploturbels）内盐分积累量较低，这可能与土壤发育深度有限以及淋溶作用有关。