RESEARCH ◥ the lake level could not exceed 1975 m asl (25 to TECHNICAL RESPONSE 50 m lower than we reconstruct) due to a low divide upstream of the dam (3); however, Han’s datum is obtained from Google Earth, whereas ARCHAEOLOGY a more accurate 1:50,000 topographic map shows that it is ~2010 m asl, within our range. More- over, the sharp crest at this site suggests that it Response to Comments on “Outburst mayhavebeenloweredbymasswastingoverthe past 4000 years. flood at 1920 BCE supports Huang et al.(4) argue that there is no sedi- mentary evidence to support the maximum level historicity of China’s Great Flood of the dammed lake. This is true because the lake with level above 1890 m asl only existed for a few months, and at its peak (~2000 to 2025 m and the Xia dynasty” asl), only for a few days, too short to leave behind sediments that would have survived subsequent Qinglong Wu,1,2* Zhijun Zhao,1,2 Li Liu,3† Darryl E. Granger,4 Hui Wang,5 subaerial exposure. The lacustrine (not fluvial) sediments in Jishi Gorge represent the remnant David J. Cohen,6† Xiaohong Wu,7 Maolin Ye,5 Ofer Bar-Yosef,8 Bin Lu,9 Jin Zhang,10 lake, which persisted long after the breach and Peizhen Zhang,11 Daoyang Yuan,12 Wuyun Qi,5 Linhai Cai,13 Shibiao Bai1,2 was gradually filled in (1). Lacustrine sediment in Jishi Gorge was previ- Downloaded from Wu et al., Han, and Huang et al. question our reconstruction of a large outburst flood ously dated to ~8000 to 5500 years before the and its possible relationship to China’s Great Flood and the Xia dynasty. Here, we clarify present (B.P.) [e.g., (9, 10)] using optically stimu- misconceptions concerning geologic evidence of the flood, its timing and magnitude, lated luminescence (OSL) and radiocarbon. How- and the complex social-cultural response. We also further discuss how this flood may be ever, due to incomplete bleaching, OSL ages may related to ancient accounts of the Great Flood and origins of the Xia dynasty. be considerably older than their true depositional ages. Also, because total organic carbon samples http://science.sciencemag.org/ ur discovery of a tremendous outburst itistheonlyplaceintheadjacentupperYellow [e.g., (10)] may include older carbon, and because flood of the Yellow River, which can pos- River watershed with the appropriate rock types. charcoal samples may have been redeposited (i.e., siblybetiedtoChina’sGreatFloodlegend We did not, as suggested by (4), confuse the they are in secondary deposits after having been (1), has provoked controversy among schol- OFS with landslide deposits (Fig. 1) or the typical moved postdepositionally by water), they only O 14 ars, represented by the three Comments fluvial gravel of the Yellow River [Fig. 2F in (4)]. provide a maximum C age (or terminus post by Wu et al., Han, and Huang et al.(2–4)towhich On the other hand, the well-sorted coarse sand quem) for the lake sediment, as we demonstrate we respond here. bed (Fig. 1E) [figure 2G in (4)] misidentified as in (1). The younger charcoal material (2020 to Outburst flood sediments (OFS) described in a tributary flash flood deposit in (4)bearsabun- 1056 BCE, calibrated) within the dammed-lake (1) provide direct evidence of the flood but have dant greenschist clasts and is actually OFS. sediments (1) therefore supersedes these previous been overlooked or misinterpreted by (2–4). At Contrary to Comments (2, 4), we did notice the limiting ages [e.g., (9, 10)] and provides a closer the Lajia site, OFS are deposited over the ground red mud beds at the Lajia site [figures S1 and S5C boundary. on February 22, 2019 surface, filled in collapsed cave dwellings, and in (1)],whichareeasilydistinguishablefromOFS. The estimation of maximum discharges both at even are found within pottery vessels [fig. S5 in We never took the red mud matrix surrounding the dam and the Lajia site are questioned by Han (1)]. Previous studies (5, 6) called the OFS “black some skeletal remains [figure 1, G and I, in (4)] (3). We note that the first five formulas in table sands” and took them to be sand boils from earth- as OFS as Huang et al.note(4). Previous studies S3 in (1) are empirical equations mainly based on quake liquefaction or gully flood deposits. How- (5, 6) wrongly identified the red muds as deposits relatively small outburst floods and that all are ever, these “black sands,” with abundant greenschist from extreme flooding of the Yellow River induced based on logarithmic regressions through data and little quartz, are very different from other by climate change and also as responsible for de- with a spread of >0.3 log units at 95% confidence. Yellow River sedimentary deposits, which contain stroying the Lajia settlement. Actually, the red mud The uncertainty in any particular model is thus a abundant quartz but almost no greenschist. They beds are locally derived from mudflows (7, 8)or factor of two or more at 95% confidence. As for couldonlyhaveoriginatedinJishiGorge,because gully floods that occurred at Lajia before, during, Han’s challenge of our estimation of the maxi- and after the Qijia culture occupation period. We mum discharge with the Ritter formula (3), we 1School of Geography Science, Nanjing Normal University, simply did not discuss the mudflow deposits over- clearly explained our rationale that this is a max- Nanjing 210023, China. 2Jiangsu Center for Collaborative lying the OFS (1) because they are unrelated to imum estimate (1). The peak stage of an outburst Innovation in Geographic Information Resource Development and the outburst flood. flood, especially for those from natural landslide 3 Application, Nanjing, Jiangsu 210023, China. Department of East Wu et al.(2) argue that the skeletons within the dams, is not transient, so that Manning’sformula Asia Languages and Cultures, Stanford University, CA 94305, USA. 4Department of Earth, Atmospheric, and Planetary houses at the Lajia site show in situ burial fea- is applicable in estimating the peak discharges of Sciences, Purdue University, West Lafayette, IN 47907, USA. tures instead of “flooding burial scenarios.” We outburst floods. To avoid overestimating the peak 5Institute of Archaeology, Chinese Academy of Social Sciences, are arguing that the collapsed cave dwellings discharge, we deduct the portion AE of the cross 6 Beijing 100710, China. Department of Anthropology, National buried the victims during the earthquake, pro- section near Lajia [figure S6C in (1)], which likely Taiwan University, Taipei 10617, Taiwan, R.O.C. 7School of Archaeology and Museology, Peking University, Beijing 100871, tecting their buried remains from reworking by eroded after this outburst flood. China. 8Department of Anthropology, Harvard University, the outburst flood ~6 to 9 months later. Han obtained an empirical attenuation equa- Cambridge, MA 01238, USA. 9China Coal Technology & Engineering Han (3)andHuanget al.(4) seem to have been tion for discharge of outburst floods from pub- ’ 10 Group Corp Xian Research Institute, Xi an 710077, China. Institute confounded by the maximum lake level at the time lished data, and, using it, he calculates discharge of Geology, Chinese Academy of Geological Sciences, Beijing 3 –1 100037, China. 11School of Earth Science and Geological of flooding [2000 to 2025 m above sea level (asl)] at the Lajia site as 10,800 m s (3). This value Engineering, Sun Yat-sen University, Guangzhou 510275, China. versus the level of the remnant lake (~1890 m asl) can be falsified right away because it is too small 12Lanzhou Institute of Seismology, China Earthquake Administration, that persisted after the dam failure. We recon- to reach the height of the observed OFS (1). The 13 Lanzhou 730000, China. Qinghai Provincial Institute of Cultural struct the level of the initial landslide dam from reliability of his equation (3) can also be disproven Relics and Archaeology, Xining 810007, China. *Corresponding author. Email: [email protected] its remnants preserved on the left bank of the by comparison with a well-gauged large outburst †These authors contributed equally to this work. Yellow River [figure S2A in (1)]. Han argues that flood (11)(Fig.2). Wu et al., Science 355, 1382e (2017) 31 March 2017 1of3 RESEARCH | TECHNICAL RESPONSE Wu et al.(2)andHan(3) criticize us for ne- glecting a recently refined date of 1750 BCE for the beginning of the Erlitou culture (17). The Erlitou culture refers to an assemblage of mate- rial remains distributed across many sites in cen- tral China. The Erlitou site—its type site—became the largest center of this culture, but the site itself dates later than the earliest sites of this regional culture. Carbonized seeds from Erlitou culture de- posits at the Huizui site, 15 km from the Erlitou site, for example, have yielded calibrated radio- carbon dates of ~1900 BCE (18). Thus, the ~1750 BCE date can represent the beginning of the Erlitou site yet not the start of the Erlitou culture. Of course, further systematic dating of other sites is needed. Citing (19), Han (3) also argues that the appear- ance of bronze vessels at the Erlitou site after ~1700 BCE marks the beginning of the Bronze Age in China. We would emphasize that the earliest cast bronze is seen in knives from the Downloaded from Majiayao culture in the Upper Yellow River re- gion by the end of the third millennium BCE, and small-scale copper-based metallurgy (includ- ing bronze casting) flourished in Xinjiang and Gansu by ~2000 to 1800 BCE (20–22). Although Erlitou bronzes mark the appearance of large- http://science.sciencemag.org/ scale casting under elite patronage (23), this is only one aspect of a larger process of sociopolitical change that begins earlier.