气候变化领域集成服务门户(CCPortal): Distinct periods of fan aggradation and incision for tributary valleys of different sizes along the Bailong River; eastern margin of the Tibetan Plateau

CCPortal

DOI	10.1016/j.geomorph.2020.107490
	Distinct periods of fan aggradation and incision for tributary valleys of different sizes along the Bailong River; eastern margin of the Tibetan Plateau
	Li Y.; Meng X.; Stevens T.; Armitage S.; Bian S.; Chen G.; He J.
发表日期	2021
ISSN	0169555X
卷号	373
英文摘要	Understanding the mechanisms of fan incision/aggradation provides key insights into the dynamics of fan evolution and hazardous fan-forming processes. This paper focuses on the discrepancy in fan evolution for two nearby valleys of different catchment areas along the Bailong River. Specifically, we study fan evolution in the small-sized CJB valley (watershed area being 1.1 km2) using sedimentary analyses and 14C dating. Sedimentary logging of seven exposed profiles indicates that mudflows and debris flows are the primary fan-forming processes. Seven samples were taken from paleosols developed in mudflow sediments, and the humin fraction was extracted for 14C dating. These ages constrain the fan aggradation period to between 10 and 4.9 cal kyr BP, and then the incision period occurred after 4.9 cal kyr BP. As the mudflow sediments may contain organic matter from hillslope legacies, the fan aggradation period may be later than the 14C ages defined in this study. In any case, the time of fan incision/aggradation in CJB is younger than that of the GLP valley (watershed area being 20 km2) where fan aggradation occurred in 21.7–7 ka and incision occurred afterward. The fan aggradation period defined by the 14C ages in CJB is consistent with an alluvial fan of similar thickness in the southeastern Tibetan Plateau and two other fans along the Bailong River. This consistency may suggest a plausible climatic control on fan evolution for small-sized tributary valleys, while the inconsistency with the larger GLP valley may suggest different climate-response regimes for tributary valleys of different sizes. More research on similar types of alluvial fans and cross-validation of different dating methods is needed. © 2020
英文关键词	Aggradation and incision; Alluvial fan; Bailong River; Eastern Tibetan Plateau
语种	英语
scopus关键词	Geomorphology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/158316
作者单位	School of Earth Sciences; Lanzhou University; Lanzhou; 730000; China; Department of Earth Sciences; Uppsala University; Villavägan 16; Uppsala; 75236; Sweden; Center for Quaternary Research; Department of Geography; Royal Holloway University of London; Egham; Surrey TW20 0EX; United Kingdom; College of Earth and Environmental Sciences; Lanzhou University; Lanzhou; 730000; China
推荐引用方式 GB/T 7714	Li Y.,Meng X.,Stevens T.,et al. Distinct periods of fan aggradation and incision for tributary valleys of different sizes along the Bailong River; eastern margin of the Tibetan Plateau[J],2021,373.
APA	Li Y..,Meng X..,Stevens T..,Armitage S..,Bian S..,...&He J..(2021).Distinct periods of fan aggradation and incision for tributary valleys of different sizes along the Bailong River; eastern margin of the Tibetan Plateau.,373.
MLA	Li Y.,et al."Distinct periods of fan aggradation and incision for tributary valleys of different sizes along the Bailong River; eastern margin of the Tibetan Plateau".373(2021).