A quantitative analysis on the sources of dune sand in the Hulun Buir Sandy Land：application of stepwise discriminant analysis （SDA） to the granulometric data
摘要
Quantltatively determining the sources of dune sand uis one of the problems necessarily and urgently to be solved in aeolian landforms and desertification research. Based on the granulometric data of sand materials from the Hulun Buir Sandy Land, the paper employs the stepwise discriminant analysis technique (SDA) for two groups to select the principal factors determining the differences between surface loose sediments. The extent of similarity between two statistical populations can be described quantitatively by three factors such as the number of principal variables, Mahalanobis distance D^2 and confidence level α for F-test. Results reveal that: 1) Aeolian dune sand in the region mainly derives from Hailar Formation (Q3), while fluvial sand and palaeosol also supply partially source sand for dunes; and 2) in the vicinity of Cuogang Town and west of the broad valley of the lower reaches of Hailar River, fluvial sand can naturally become principal supplier for dune sand.