Drainage basin lithology impact on tlle channel alluvium composition at the Lena and Aldan rivers

Abstract

The substrate lithology impact on petrographic spectra of alluvium is considered with reference to two largest East Siberian rivers such as Lena and Aldan. The desintegration character is proved to influence both granulometry and petrography of alluvium. Coefficients of variation are obtained for petrographic composition in three fraction for different parts of rivers. The correlation was established between petrographic spectrum of alluvium and rocks lithology within a drainage basin. A sequence of rocks is established according to their resistance to abrasion during the channel transport as well as relation of local material (provided by small rivers) and «transit» which is moved along the trunk valleys.