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以及南美阿塔卡马沙漠选定的研究地点，通过宇宙成因3He暴露年龄测定，验证了沙漠路面形成的风成/成土沉积模型；(2)通过实地和实验室调查，阐明作用于和改变路面的成土过程（如水泡状A层形成）、物理过程（如土壤变形和颗粒运动）和生物过程（如植物生长引起的碎屑位移）的类型；(3)为古火星风化层发育的行星研究建立一个潜在的地球模拟。玄武岩熔岩流表面发育的路面碎屑的初始宇宙形成表面暴露年龄证实，自熔岩流喷发以来，碎屑一直保留在路面表面。传统和实验方法的土壤变形和碎屑运动在三维空间将完成在选定的研究地块利用地下和地面测量。这些数据集将与(1)研究地块内的土壤剖面性质和发育情况进行比较，(2)路面和地下各级碎屑的化学风化参数，以及(3)显示植物分布与路面性质以及风成增生地幔中生物扰动和碎屑浓度之间关系的植物样带和沟槽数据。这项研究将有助于使用路面进行测绘的野外地质学家、使用路面进行景观测年的地貌学家和地质年代学家、研究路面上文化文物分布的考古学家、重建世界沙漠地区地表古环境的第四纪地质学家、还有行星地质学家，他们在地球上寻找火星风化层演化的类似物。

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.