Source supply processes of the megadune field in the Badain Jaran Sand Sea
Liang, A.M.; Dong, Z.B.; Zhang, Z.C.; Zhang, Y.F.; Ma, Y.J.; Su, Z.Z.; Lizaga, I. (2024). Source supply processes of the megadune field in the Badain Jaran Sand Sea. J. Soils Sediments 24: 438-448. https://dx.doi.org/10.1007/s11368-023-03641-5 In: Journal of Soils and Sediments. Springer: Heidelberg; Berlin. ISSN 1439-0108; e-ISSN 1614-7480, more |  |
| Keyword | | | Author keywords | Megadune; Geochemical analysis; Provenance; Sediment supply processes; Badain Jaran Sand Sea |
| Authors | | Top | - Liang, A.M.
- Dong, Z.B.
- Zhang, Z.C.
- Zhang, Y.F.
| - Ma, Y.J.
- Su, Z.Z.
- Lizaga, I., more
| |
| Abstract | PurposeAlthough the formation mechanism of the megadunes in the Badain Jaran Sand Sea has received considerable research attention, their provenance and sand accumulation processes are still poorly understood. Therefore, this study aims to identify the provenance of the megadunes and clarify the spatial and temporal characteristics of their source supply processes.Materials and methodsWe collected megadune sands in the Badain Jaran Sand Sea and sediments from their potential source regions (i.e., the Heihe-Altay alluvial fan, Heihe River, Beida-Yabrai alluvial fans, and Gulunai-Guaizi dry lakes). We analyzed the geochemical compositions of these sediments using X-ray fluorescence spectrometer. Source identification was conducted using robust K/Ba and K/Rb ratios and the multidimensional scaling (MDS) method. Based on fluvial-aeolian system distribution and comparison with drilling cores, the spatial and temporal source supply processes of the megadunes were determined.Results and discussionThe K/Ba vs. K/Rb biplot showed that the Heihe-Altay alluvial sediment, Heihe River fluvial sand, and the Beida-Yabrai alluvial sediment samples were similar to the sand in the megadunes. Similarly, MDS result showed that these sources had similarities to the megadune sand, indicating that they were the sources of the megadune sand. Based on the distribution of fluvial-aeolian systems, we conclude that the sediments from the Qilian Mountains and Altay Mountains were first mixed in the Heihe River, after which they were sorted and transported by the northwest wind to the megadune field. The Beida-Yabrai Mountains delivered source sediments to the sand sea via short-lived runoff episodes and southeast winds, which were not as significant as those previously described. These sands finally built megadunes in two directions, namely from the northwest to the southeast and its opposite direction due to the prevailing northwest wind and local air circulation from the slipface. By comparing drilling cores from within and near the sand sea, we found that fluvial sediments were prevailing in the lower reaches of the Heihe River during Marine Isotopic Stage (MIS) 4 and MIS 2, when the megadunes rapidly migrated. However, the Heihe-Altay alluvial fan formed since the Late Pleistocene when the sand sea began to form, indicating a more extended source supply history.ConclusionsOur results indicated that the Heihe-Altay alluvial sediments, the Heihe River fluvial sand, and the Beida-Yabrai alluvial sediments were the sources of the megadune sand. The sediments transported to the dune field by fluvial-aeolian systems at the sand sea scale and accumulated on the megadunes from both windward and leeward directions at the individual dune scale. Temporally, the Heihe-Altay alluvial fan may be a continuous source of sediments for the development of the megadunes, and the Heihe River may have contributed to their rapid migration during MIS 4 and MIS 2.
|
|
