ORIGIN OF ALLUVIAL FANS, WHITE MOUNTAINS, CALIFORNIA AND NEVADA1

摘要: AT the base of flanks a desert mountain, conditions are propitious for deposition by streams coming from highlands. There is usually decrease in gradient at canyon mouths, and all undergo reduction velocity transporting power these sites. Velocity loss due both to lessened volume seepage into loose, permeable materials. Deposition natural result, alluvial fans landforms produced. Alluvial built concentration movement debris trunk canyons accumulate foot mountain mass. Their upper portions separated interfan depressions, but their lower surfaces coalesce form piedmont plains, or bajadas. This study contribution toward an understanding depositional processes produced them southwestern United States. The evidence comes White Mountains California Nevada, high-standing range western margin Great Basin. Particular attention was given flank mountains, larger associated drainage basins on east side were also investigated. Conclusions reached about fan formation thus based upon features diverse morphology size.