The Pluvial Lake Palomas-Samalayuca Dunes system.

摘要

A lacustro-aeolian system formed by the Pluvial Lake Palomas (PLP), the Samalayuca Dunes (SMD) and a connecting aeolian corridor is found in the central Chihuahuan Desert of North America approximately 50 km upwind (SW) of the binational Paso del Norte metroplex. The system is described by its three individual components. They comprise one of the largest paleo-lacustrine (Pleistocene) environments in the Chihuahuan Desert (PLP), one of the largest and least-studied sand seas of North America (SMD), and a newly described and geomorphically heterogeneous aeolian corridor connecting the two.The Chihuahuan Desert has been a major and underappreciated dust production region of North America. The PLP - SMD system includes many of the prime dust "hotspots" of the Chihuahuan Desert. The individual parts of the system are analyzed separately and specific emphasis is given to previously undescribed or unidentified sedimentological, geomorphological and geochemical characteristics.An assessment of the dust emission potential based on a reconnaissance of the sedimentological and surface textural conditions and dynamics of each of the PLP sub-basins and other specific areas is presented. These conditions support placing the lacustrine sub-system and its related alluvial and fluvial areas as a major mineral aerosol "hot spot" in North America. Sedimentological and geochemical properties of dust-producing sediments in eight PLP sub-basins (Bolson de los Muertos, central PLP, Laguna Santa Maria, Laguna El Fresnal, Laguna Guzman, Rio Casas Grandes Valley, Laguna Palomas, and Laguna de Patos) and one adjacent basin (Laguna Ascension) are also comprehensively described for the first time.The presented research identifies and describes the geomorphology, sedimentology and elemental concentrations of a newly described aeolian corridor connecting the PLP and SMD, adding to the scant scientific literature regarding these aeolian corridors.A revised geomorphic description and identification of dune types in the SMD (including two previously unidentified and undescribed dune forms) is also presented, as well as documentation of the complex interactions among the different types of dunes of the sand sea.Overall, this study elucidates the intricate linkage between the three areas as one geomorphic system and its combined effects on downwind populations as a mineral aerosol source.