quaternary Article Extension of the Upper Yellow River into the Tibet Plateau: Review and New Data Zhengchen Li 1, Xianyan Wang 1,* , Jef Vandenberghe 2 and Huayu Lu 1 1 School of Geography and Ocean Science, Nanjing University, Nanjing 210023, China; [email protected] (Z.L.); [email protected] (H.L.) 2 Department of Earth Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands; [email protected] * Correspondence: [email protected] Abstract: The Wufo Basin at the margin of the northeastern Tibet Plateau connects the upstream reaches of the Yellow River with the lowland catchment downstream, and the fluvial terrace sequence in this basin provides crucial clues to understand the evolution history of the Yellow River drainage system in relation to the uplift and outgrowth of the Tibetan Plateau. Using field survey and analysis of Digital Elevation Model/Google Earth imagery, we found at least eight Yellow River terraces in this area. The overlying loess of the highest terrace was dated at 1.2 Ma based on paleomagnetic stratigraphy (two normal and two reversal polarities) and the loess-paleosol sequence (12 loess- paleosol cycles). This terrace shows the connections of drainage parts in and outside the Tibetan Plateau through its NE margin. In addition, we review the previously published data on the Yellow River terraces and ancient large lakes in the basins. Based on our new data and previous researches, we conclude that the modern Yellow River, with headwaters in the Tibet Plateau and debouching in the Bohai Sea, should date from at least 1.2 Ma. Ancient large lakes (such as the Hetao and Sanmen Lakes) developed as exorheic systems and flowed through the modern Yellow River at that time. Citation: Li, Z.; Wang, X.; Vandenberghe, J.; Lu, H. Extension of Keywords: terraces; loess-paleosol sequence; Yellow River; magneto-stratigraphy; Northeastern the Upper Yellow River into the Tibet Tibet Plateau Plateau: Review and New Data. Quaternary 2021, 4, 14. https:// doi.org/10.3390/quat4020014 1. Introduction Academic Editor: Pierre Antoine The evolution of the Yellow River system is influenced by tectonic movements, climatic change, and human activity [1,2]. Meanwhile, the uplift of the Tibet Plateau reinforces the Received: 8 February 2021 strength of the Asian Monsoon and plays an important role in global climate change [3]. Accepted: 20 April 2021 In turn, rapid erosion may lead to a crust isostatic rebound and cause tectonic activity [4]. Published: 25 April 2021 Moreover, the river network reorganization influenced by the tectonic activities, especially for larger river, may have affected biodiversity and even hominin migration [5,6]. As a Publisher’s Note: MDPI stays neutral significant geological event due to the collision between the Indian and Eurasian plates [7,8], with regard to jurisdictional claims in the uplift of the Tibet Plateau has an important influence on global climate, and results in published maps and institutional affil- the aridification of northwestern China [9] and the re-configurated drainage systems in iations. Asia. The Yellow River, the second-longest river in China, originates from the Tibet Plateau, flows through isolated basins including rift valleys and finally drains in the Bohai Sea (Figure1). Unraveling the evolutionary history of the Yellow River may help understand the uplift of the Tibet Plateau. Copyright: © 2021 by the authors. The origin and evolutionary history of the Yellow River have been debated for a Licensee MDPI, Basel, Switzerland. long time with different viewpoints. An hypothesis suggests the Yellow River might have This article is an open access article extended from downstream to upstream through headward erosion into the Tibet Plateau, distributed under the terms and cutting across a series of alternating basin-mountain structures while capturing a series of conditions of the Creative Commons endorheic drainage systems [10–12]. In such a scenario, some basins may have developed Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ a spillover to join the Yellow River drainage [10,11]. The final extension of the entire Yellow 4.0/). River, from the Bohai Sea up to its present source, would have been of relatively young age Quaternary 2021, 4, 14. https://doi.org/10.3390/quat4020014 https://www.mdpi.com/journal/quaternary Quaternary 2021, 4, x FOR PEER REVIEW 2 of 18 Quaternary 2021, 4, 14 a spillover to join the Yellow River drainage [10,11]. The final extension of the entire2 ofYel- 18 low River, from the Bohai Sea up to its present source, would have been of relatively young age (mid-Pleistocene). In a second scenario, it is suggested that the current Yellow (mid-Pleistocene).River has already existed In a second since scenario,at least pre it- isQuaternary suggested and that even the currentpre-Neogene Yellow time, River while has alreadypaleo lakes existed developed since at in least the pre-Quaternary basins as coexisting and evendammed pre-Neogene lakes [13] time,. In the while third paleo scenario, lakes developedthe modern in Yellow the basins River as coexistingfinally formed dammed after lakes the [Hetao13]. In or the Sanmen third scenario, paleo lakes the modern finally Yellowwent extinct, River therefore finally formed implying after a thevery Hetao young or age Sanmen of the paleoYellow lakes River finally origin went (late extinct,Pleisto- thereforecene) [14] implying. a very young age of the Yellow River origin (late Pleistocene) [14]. To provideprovide moremore relevantrelevant data,data, wewe focusedfocused onon thethe fluvialfluvial terracesterraces inin thethe WufoWufo BasinBasin at the northeasternnortheastern boundary of the Tibet PlateauPlateau inin thisthis study.study. The Yellow RiverRiver cutscuts throughthrough thethe WufoWufo BasinBasin andand flowsflows intointo riftrift basinsbasins outsideoutside thethe TibetanTibetan Plateau,Plateau, suchsuch asas thethe Yinchuan, Hetao,Hetao, andand SanmenSanmen BasinsBasins (Figure(Figure1 1).). Thus,Thus, thethe WufoWufo Basin, Basin, which which connects connects thethe upperupper YellowYellow RiverRiver inin thethe TibetTibet PlateauPlateau withwith downstreamdownstream reachesreaches outsideoutside thethe TibetTibet Plateau, is a prominent place to investigate the evolution history of the Yellow RiverRiver intointo thethe TibetTibet PlateauPlateau (Figure(Figure1 1).). UntilUntil now,now, the the data data of of terraces terraces near near the the boundary boundary between between thethe Tibet Plateau Plateau and and the the Ordos Ordos block block ha haveve remained remained lack lack.. Thus, Thus, the correlation the correlation and con- and connectionnection history history of the of Yellow the Yellow River River drainage drainage reach reachinging inside inside and outside and outside of the of Tibet the Tibet Plat- Plateaueau is still is still debated. debated. These These fluvial fluvial terraces terraces are are discussed discussed in in the the framework framework of of all available terraceterrace information of the Yellow RiverRiver [[1515––1717]] includingincluding thethe depositionaldepositional historyhistory ofof thethe delta [[1818–20]],, andand wewe aimaim toto untangle thethe ageage ofof the connection betweenbetween thethe TibetTibet PlateauPlateau and the ocean through thethe YellowYellow River.River. FigureFigure 1.1. StudyStudy areaarea ofof thethe Wufo Wufo Basin Basin (red (red star) star) with with the the background background of of the the Yellow Yellow River River catchment. catchment (a). Topography(a) Topography of the of Yellowthe Yellow River River catchment catchment presented presented by Digital by Digital Elevation Elevation Model Model (DEM) (DEM data) (SRTMdata (SRTM V4 90 V4 m resolution),90 m resolution), and the and extension the exten- of loesssion of deposit loess deposit in north in China. north (China.b) Overview (b) Overview of the Yellow of the Yellow River drainage River drainage and major and basinsmajor alongbasins the along Yellow the Yellow River valley River withvalley the with background the background of morphologic of morphologic features features expressed expressed by DEM by dataDEM (SRTM data (SRTM V4 90 mV4 resolution 90 m resolution data). Reddata) lines. Red point lines point to the previous study areas with references marked in the grey boxes. Black lines mean the boundary of the Yellow to the previous study areas with references marked in the grey boxes. Black lines mean the boundary of the Yellow River River catchment. Dark blue polygons indicate the modern lakes and light blue polygons indicate basins that were once catchment. Dark blue polygons indicate the modern lakes and light blue polygons indicate basins that were once occupied occupied by paleo-lakes. REGB: Ruoergai Basin; TDB: Tongde Basin; GHB: Gonghe Basin; GDB: Guide Basin; LXB: Linxia byBasin; paleo-lakes. YCB: Yinchuan REGB: RuoergaiBasin; HTB: Basin; Hetao TDB: Basin; Tongde SMB: Basin; Sanmen GHB: GongheBasin; SMG: Basin; Sanmen GDB: Guide Gorge; Basin; LZ: Lanzhou LXB: Linxia City; Basin; YC: YCB:Yin- Yinchuanchuan City; Basin; LT and HTB: PX Hetao are LingTai Basin; and SMB: PuXian Sanmen loess Basin; site, SMG: respec Sanmentively. Gorge; LZ: Lanzhou City; YC: Yinchuan City; LT and PX are LingTai and PuXian loess site, respectively. Quaternary 2021, 4, x FOR PEER REVIEW 3 of 18 Quaternary 2021, 4, 14 3 of 18 2. Regional Setting 2. Regional Setting 2.1. Geographical Setting 2.1. Geographical Setting 2 The Yellow River,