Zha, X., Huang, C., Pang, J. and Li, Y. 2012. Sedimentary and hydrological studies of the Holocene palaeofloods in the middle reaches of the Jinghe River. Journal of Geographical Sciences 22: 470-478.
What was done
The authors state that a palaeo-hydrological field investigation was carried out in the central portion of the Jinghe River, the middle and upper reaches of which are located in a semi-arid zone with a monsoonal climate, where slackwater deposits (SWDs) were found in bedrock gorges between Binxian county and Chunhua county of Shaanxi Province by close examination of their color, texture and structure, as well as particle size distribution, magnetic susceptibility and loss-on-ignition, and where the times of their occurrence were determined by stratigraphic correlation and optical simulated luminescence or OSL dating.
What was learned
Zha et al. report there were five palaeoflood events recorded by SWDs that were determined to have occurred between 4100 and 4000 years BP, and that these floods "corresponded exactly with palaeoflood events (4200-4000 yr BP) recorded in the middle reaches of Qishuie River," thereby demonstrating that "extraordinary flood events were common during the episode of 4200-4000 yr BP in the middle reaches of the Yellow River."
What it means
In discussing their results, the four Chinese researchers state that "during the mid-Holocene climatic optimum, global climate was warm-humid and the climate system was stable," and during this time they say "there were no flood records identified in the middle reaches of the Yellow river," citing the work of Huang et al. (2011a,b). Thereafter, however, they report that "global climatic cooling events occurred at about 4200 years BP, which was also well recorded by various climatic proxies in China," citing Zhang et al. (2004). In addition, they write that "the decline of the Neolithic Longshan Culture in the period around 4000 years BP was thought to be linked with the global cooling events," as suggested by the work of Wu et al. (2001, 2004, 2005)." And these diverse observations led them to conclude that "the extraordinary floods recorded in the middle reaches of the Jinghe River were linked to the global climatic events," which were all global cooling events. Thus, we have another manifestation of the fact that it is global cooling that leads to more frequent and extreme flooding, rather than the global warming climate alarmists claim is the culprit.
Huang, C., Pang, J., Zha, X., Su, H. and Jia, Y. 2011a. Extraordinary floods related to the climatic event at 4200 a BP on the Qishuihe River, middle reaches of the Yellow River, China. Quaternary Science Reviews 30: 460-468.
Huang, C., Pang, J., Zha, X., Zhou, Y., Su, H., Wan, H. and Ge, B. 2011b. Sedimentary records of extraordinary floods at the ending of the mid-Holocene climatic optimum along the Upper Weihe River, China. The Holocene 10.1177/0959683611409781.
Wu, W. and Ge, Q. 2005. The possibility of occurring of the extraordinary floods on the eve of establishment of the Xia Dynasty and the historical truth of Dayu's successful regulating of floodwaters. Quaternary Sciences 25: 741-749.
Wu, W. and Liu, T. 2001. 4000 a BP event and its implications for the origin of ancient Chinese civilization. Quaternary Sciences 21: 443-451.
Wu, W. and Liu, T. 2004. Variations in East Asian monsoon around 4000 a BP and the collapse of Neolithic cultures around Central Plain. Quaternary Sciences 24: 278-284.
Zhang, Q., Yang, D., Shi, Y., Ge, Z.-S. and Jiang, T. 2004. Flood events since 5000 a BP recorded in natural sediments of Zhongba Site, Chuanjiang River. Scientia Geographica Sinica 24: 715-720.Reviewed 7 November 2012