Surficial Processes and Geomorphic Evolution of Desert Pavement Landscapes

项目包括：(1)在北美西部莫哈韦沙漠和大盆地和南美洲阿塔卡马沙漠选定的研究地点，通过宇宙成因的3He暴露年龄测试沙漠路面形成的风成/土壤成因增生模型；(2)通过野外和实验室调查，阐明土壤成因(例如，A层气泡形成)、物理(例如，土壤变形和颗粒运动)和生物(例如，植物生长造成的碎屑移动)过程的类型；以及(3)建立一个潜在的陆地类比，用于火星古代风化层发育的行星研究。玄武岩熔岩流表面形成的碎屑的初始宇宙成因3He表面暴露年龄证实，自熔岩流喷发以来，碎屑一直留在路面上。在3-D空间中土壤变形和碎屑运动的传统和实验方法将在选定的研究地块使用地下和表面测量来完成。这些数据集将与(1)研究地块内土壤剖面性质和发育情况进行比较，(2)路面碎屑和地下不同水平碎屑的化学风化参数，以及(3)植物样带和沟渠数据，显示植物分布和路面性质以及风成增生地幔中生物扰动和碎屑浓度之间的关系。这项研究将有助于利用人行道测绘地图的野外地质学家、使用人行道测年景观的地貌学家和地质年代学家、研究人行道上文化遗迹分布的考古学家、重建世界沙漠地区陆地表面古环境的第四纪地质学家，以及为火星风暴层的演化寻找陆地类比的行星地质学家。

The project were (1) test the eolian/pedogenic accretionary model of desert pavement formation by cosmogenic 3He exposure age dating at selected study sites in the Mojave Desert and Great Basin of western North America and in the Atacama Desert of South America; (2) elucidate the types of pedogenic (e.g., vesicular A horizon formation), physical (e.g.,soil deformation and particle movement) and biological (e.g., clast displacement due to plant growth) processes operating on and modifying pavements by field and laboratory investigations; and (3) establish a potential terrestrial analog for planetary studies of ancient Martian regolith development. Initial cosmogenic 3He surface exposure ages on clasts from pavements developed on basaltic lava flow surfaces confirm that clasts have remained at the pavement surface since the eruption of the lava flow. Traditional and experimental methods of soil deformation and clast movement in 3-D space will be accomplished at selected study plots using subsurface and surface measurements. These data sets will be compared with (1) soil profile properties and development within the study plots, (2) chemical weathering parameters on clasts from the pavement and at various levels within the subsurface, and (3) plant transect and trench data showing relations between plant distribution and pavement properties and bioturbation and clast concentrations in the eolian accretionary mantle. This research will help the endeavors of field geologists who use pavements for mapping purposes, geomorphologists and geochronologists who use pavements for dating landscapes, archaeologists who examine cultural artifact distribution on pavements, Quaternary geologists who reconstruct paleoenvironments of land surfaces in desert regions of the world, and planetary geologists who seek terrestrial analogs for the evolution of the Martian regolith.