#1The effect of prevailing wind on shoreline landform evolution - Illustrated by the case of Buha River Delta and Hargai River Delta in the Qinghai Lake, western China Chao Liua,b, Zaixing Jianga,b a School of Energy Resources, China University of Geosciences (Beijing), Beijing, 100083, China b Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism, Ministry of Education, China University of Geosciences (Beijing), Beijing, 100083, China#2Datong Mountain Shaliu River V Haergai River Haixinshan V2 IV Buha Riyer Heishan Bird island Heima River V₁ Sankuaishi V4 V3 Qinghai South 7.7 0 20km S Gonghe Basin Ganzi River Mountain 5 4 3 Huangshui River Tuanbao Mountain الله سي Qinghai South Mountain Southern Depression Central High Northern Depression Structure map of Qinghai Lake Lithology System Series Stage Buhahe Formation Erlangjian Formation ☐ Holocene Daban Mountai III Riyue Mountain Daotanghe River N Pleistocene Quaternary Datong Mountain Hadatan Formation 000 Age (Ma) Palaeontology description Transition from the forest period to the grassland period. The forest only contain Pinus, Pieea Dietr and Populus. The herbage is composed of Chenopodiaceae, Leguminous and Artemis, indicating climate changes from warm and wet to cold and dray. Then herbages are dominant plants, which are composed of Gramineae, Chenopodiaceae, Asteraceae, Leguminosae and Salix, indicate a dry climate Forest type vegetation. The vegetation is dominated by woody plants, which is composed of Pinus, Cupressaceae, Juglans, Betula. The understory herbaceous plants are dominated by Allium, Chenopodiaceae, and Compositae, reflecting a warm and humid climate. The flora in the Upper part of Erlang Jian Formation is dominated by Pinus, indicating a cool and humid climate. Forest and grassland are mainly composed of Lily. Branch, Leguminosae, Walnut, Quercus etc., reflecting a humid climate at that time. The Upper part of Hadatan Formaiton is dominated by Pieea Dietr, Quercus and Artemisia, suggesting climiate had changed to cold, but humid climate remained. 0.0117 ? 1- Level I planation surface 2- Level II planation surface 3- Piedmont denudation surface 4- Fault O..O .O... 5- Boundary of uplift I - Datongshan Mountain uplift III- Tuanbao Mountain-Riyue Mountain uplift V1- Northern secondary rift basin IV- Habu River granben V2- Heishan -Haixinshan horst II- Ganzi River-Huangshui graben V-Qinghai Lake rift basin. V3- Southenr secondary rift basin Sandy gravel Gravelly sandstone Sandstone Siltstone Silty mudstone Muddy Transition siltstone layer Mudsonte Reddish loess layer Loess layer V4- Sankuaishi horst V5- Erlangjian horst V6- Southeastern secondary rift basin VI- Daotang River graben VII-Qinghai South Mountain uplift ①Fault system in southern margin of middle Qilian block 3 Heima River-Dari fault belt 2 Laji Mountain fault system 4 Zongwulong Mountain-Qinghai South Mountain fault belt ⑤Haiyan-Nianbaoyuze fault belt Quaternary stratigraphy of Qinghai Lake#3wind frequency A W E B S W S C N W S E E Its geographic location and remote sensing images wind N 30 km leeward side windward side |WWB = Fm/Dm Fm-lake length parallel to the dominant wind direction - Dm mean depth of the lake 75 90 105E 120 500 km Qinghai Lake Beijing Yellow River Yangtze River. Zhujiang River 30 km IWWB=106km/21m=5>3 wind driven lake ! (Nutz et al. 2018)#4N N spit lakeward 3.5 km spit open lake lagoon spit sequence of beach ridges 1 km lagoon spit open lake barrier bar lagoon spit Washover fan N sequence of beach ridges 4 km eolian dunes N rgai River spit lagoon 10 km open lake barrier 1 km Landform features of windward side#5Buha River abandoned channels distributary channels 5 km N Quanji River Landform features of leeward side Shaliu River 5 km N#6Leeward delta - Buha River Delta Buha River abandoned channels distributary channels N Mouth bars » 2015 AutoNavi Image 2015 CNES / Astrium Go 5 km 2005 景影像拍摄日期: 2015/7/25 38° 57° 44.38 北99° 50° 25.29”东海拔 5198 米 视角海拔高 River dominated delta leeward; River Wave; Bird-foot shaped; Mouth bars developed#7Evolution of Buha River Delta (1985-2019) 1985 Google Earth Image Ladsal / Copernicus 4 km N Google Earth image Landbar / Copernicus 2019 Google Earth Mere Larisa (Copernicus 4 km N lake rising; stable shape; migration of Mouth bars; river dominated 2013 N 4 km#8A Distributary channel Natural levee No waves Coastline Underwater distributary channel Swunp B SE Underwater natural levee Field photo of the estuary at Buha River Delta Distributary channel 2009-5-31 coastline 2009-5-31mouth bar 2013-8-2 mouth bar 2013-8-2 coastline Migration of the mouth bars between 2009-5-31 and 2013-8-2#9Section at the estuary of Buha River Delta Lake flow direction Channel lag deposits Current climbing ripples Planar cross-lamination Unidirectional flow structures#10Windward delta - Hargai River Delta 5km Barrier bar 1 km Wave dominated delta Windward; Wave > River; Destructional shape; Barrier bar developed#11Evolution of Hargai River Delta 1985 (1985-2019) 2013 Google Earth Image Landsat / Copernicus 2019 Google Earth inese Landsat Copernicus N 2 km 2 km Google Earth Image Landsat / Copernicus the formation of barrier bar; wave dominated N 2 km#12A land SE B lake NE land river flow river flow wave and coastal current coastal current backwater C D S land beach ridge lake Field photo of the estuary at Hargai River Delta#13A lake backwater river flow B NE SW land swampy lagoon land washover gully lake Field photo of the estuary at Hargai River Delta B NW washover gully lake barrier bar lagoon washover deposits land Field photo of the barrier bar at Hargai River Delta on a windy day SE#14Section at the estuary of Hargai River Delta washover deposits planar cross-beds Lake beach ridge swash cross-beds