Relative Influences of Climatic Change, Dust Flux, and Lithology on Soil Hydrology and Soil-Geomorphic Processes in Arid and Semiarid Transitional Environments

提出了一个多学科项目，以确定气候、尘埃通量和岩性的变化如何与沙漠环境中冲积扇上土壤景观演变的遗传联系。重要的变量可以被检查，因为研究区域包含干旱到半干旱的气候梯度，第四纪气候变化和沙尘通量的独立记录，出色的年代地层分辨率，以及岩性不同的矿床序列（花岗岩，石灰石，混合）。该项目的目标是：确定不同岩性土壤地貌过程速率的变化，确定尘埃通量、气候、地表渗透性和土壤-水平衡的时空变化，并确定这些因素的变化如何控制钙质土壤的形成。与气候和沙尘通量时空变化相关的土壤地貌特性将通过对土壤的实地描述和实验室分析、扇面形态测量以及土壤和扇面水文评价来记录。本研究的一个新方法是将经验测量的土壤地貌特性与土壤水分运动和碳酸盐成土聚集的计算机模拟相结合。土壤碳酸盐的同位素研究将提供关于钙质土壤形成的时间和过程以及古气候的额外信息。结果将提供信息，用于制定识别土壤地貌系统中保存的气候变化信号的标准，用于评估气候变化对土壤地貌成分比率的影响，这些成分通常用于年龄估计，并用于开发与美国西南部其他第四纪沉积物的区域地层相关性

A multi-disciplinary project is proposed to determine how variations in climate, dust flux, and lithology are genetically linked to soil-landscape evolution on alluvial fans in desert environments. Important variables can be examined because the study area contains an arid to semi-arid climatic gradient, an independent record of Quaternary climate change and dust flux, excellent chronostratigraphic resolution, and sequences of lithologically distinct deposits (granite, limestone, mixed). The project objectives are to: determine variation in rates of soil- geomorphic processes among different lithologies, determine spatial and temporal changes in dust flux, climate, surface permeability, and soil-water balance, and determine how changes in these factors control formation of calcic soils. Soil-geomorphic properties related to spatial and temporal changes in climate and dust flux will be documented through field descriptions and laboratory analysis of soils, morphometric measurements of fan-surfaces, and evaluation of soil and fan-surface hydrology. A novel approach of this study will be to integrate empirically measured soil- geomorphic properties with computer simulations of soil water movement and pedogenic accumulation of carbonate. Isotopic studies of soil carbonate will provide additional information concerning the timing and processes of calcic soil formation and paleoclimate. Results will provide information for developing criteria for recognition of signals of climatic change preserved in soil- geomorphic systems, for evaluating the effect of climate change on the rates of soil-geomorphic components commonly used for age estimations, and for developing regional stratigraphic correlations to other Quaternary deposits in the southwest U.S.