Which is the dominant source for the aeolian sand in the Badain Jaran Sand Sea, Northwest China: Fluvial or gobi sediments?

Abstract

Fluvial and gobi sediments play significant roles in the formation of modern sand seas and their evolution. However, little is known about their respective source contributions, especially in quantitative terms. In the present study, we selected the Badain Jaran Sand Sea in Northwest China to quantitatively identify the sediment sources. To achieve this goal, we collected Heihe River sand and gobi sediments (Ejin gobi and the Beida–Yabrai gobis) as the potential sand sources. We performed provenance identification based on robust geochemical indicators, and found that both of these potential sources provided sand materials to the sand sea. Our quantitative analysis based on novel fingerprinting methods, namely consensus ranking (CR) and consistent tracer selection (CTS), suggested that the gobi sediments supplied more sand than the fluvial sand, accounting for 76.85 % and 23.15 % of the total (goodness of fit is 95.8 ± 3.89), respectively. Therein, the Ejin gobi was the dominant source for most regions of the sand sea (63.17 ± 21.43 %), but the Heihe River mainly fed sand source to the southern part of the sand sea (23.15 ± 18.66 %) and the Beida–Yabrai gobis provided the most sand to regions near the fan (13.68 ± 11.49 %). The source supply areas largely control above contribution difference. Our results demonstrate the critical role of gobi sediments for sand accumulation of the Badain Jaran Sand Sea.