Impact of monsoonal climatic change on Holocene overbank flooding along Sushui River,middle reach of the Yellow River,China |
| |
| Institution: | 1. Department of Geography, Shaanxi Normal University, Xi’an, Shaanxi 710062, PR China;2. State Key Laboratory of Loess and Quaternary Geology, CAS, Xian, Shaanxi 710075, PR China;1. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China;2. Centre for Hydrological and Ecosystem Science (CHES), Department of Geography, Loughborough University, Loughborough, LE11 3TU, UK;3. Ningbo Municipal Institute of Cultural Relics and Archaeology, Ningbo, 315000, China;4. Shanghai Museum, Shanghai, 200003, China;1. State Key Laboratory of Loess and Quaternary Geology, Center for Excellence in Quaternary Science and Global Change, Institute of Earth Environment, Chinese Academy of Science, Xi''an 710061, China;2. Institute of Global Environmental Change, Xi''an Jiaotong University, Xi''an 710049, China;3. Open Studio for OCCEC, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China;4. University of Chinese Academy of Sciences, Beijing 100049, China;5. Department of Geography and Environmental Sciences, Northumbria University, NE1 8ST, United Kingdom;6. Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, USA;1. School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;2. Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada;1. University Grenoble Alpes, CNRS, IRD, G-INP, Institute for Geosciences and Environmental Research, Grenoble, France;2. Climatic Change and Climate Impacts, Institute for Environmental Sciences, University of Geneva, Geneva, Switzerland;3. Dendrolab.ch, Department of Earth Sciences, University of Geneva, Geneva, Switzerland;4. Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, Spanish National Research Council CSIC, Serrano 119, 28006 Madrid, Spain;5. CNRS UMR 6249, Laboratoire Chrono-Environnement, UFR des Sciences et Techniques, Université de Bourgogne-Franche-Comté, Besançon, France;6. Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Telegrafenberg, 14473 Potsdam, Germany;7. Department F.A. Forel for Aquatic and Environmental Sciences, University of Geneva, Geneva, Switzerland;8. Department of Earth Science and Bjerknes Centre for Climate Research, University of Bergen, Bergen, Norway;9. KU Leuven, Dept. Egyptology, Belgium |
| |
| Abstract: | In the semiarid loess regions, slackwater deposition of overbank flooding over the piedmont alluvial plains was episodic and alternated with dust accumulation and soil formation throughout the Holocene. The records of past hydrological events are therefore preserved within the architecture of loess and soils and are protected from subsequent erosion and destruction. Several Holocene loess–soil sequences with the deposits of overbank flooding over the semiarid piedmont alluvial plains in the southeast part of the middle reaches of the Yellow River drainage basin were investigated by field observation, OSL and C14 dating, measurement of magnetic susceptibility, particle-size distribution and chemical elements. This enables the reconstruction of a complete catalog of Holocene overbank flooding events at a watershed scale and an investigation of hydrological response to monsoonal climatic change as well. During the Holocene, there are six episodes of overbank flooding recorded over the alluvial plain. The first occurred at 11,500–11,000 a BP, i.e. the onset of the Holocene. The second took place at 9500–8500 a BP, immediately before the mid-Holocene Climatic Optimum. After an extended geomorphic stability and soil formation, the third overbank flooding episode came at about 3620–3520 a BP, i.e. the late stage of the mid-Holocene Climatic Optimum, and the floodwater inundated and devastated a Bronze-age town of the Xia Culture built on the alluvial plain, and therefore the town was abandoned for a period of ca 100 years. During the late Holocene, the alluvial plain experienced three episodes of overbank flooding at 2420–2170, 1860–1700 and 680–100 a BP, respectively. The occurrence of these overbank flooding episodes corresponds to the anomalous change in monsoonal climate in the middle reaches of the Yellow River drainage basin when rapid climate change or climatic decline occurs. During at least the last four episodes, both extreme floods and droughts occurred and climate departed from its normal condition, which was defined as a balanced change between the northwestern continental monsoon and southeastern maritime monsoon over time. Great floods occurred as a result of extreme rainstorms in summers caused by rare intensive meridianal airflows involving northwestward moving tropical cyclone systems from the Pacific. These results could be applied to improve our understanding of high-resolution climatic change, and of hydrological response to climatic change in the semiarid zones. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
