Luminescence and Radiocarbon Chronologies for the Xindian Culture Site of Lamafeng in the Guanting Basin on the NE Edge of the Tibetan Plateau

Quaternary Geochronology 10 (2012) 394e398

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Research paper Luminescence and radiocarbon chronologies for the Xindian Culture site of Lamafeng in the Guanting Basin on the NE edge of the Tibetan Plateau

GuangLiang Hou a,b, ZhongPing Lai b,c,*, YongJuan Sun c,d, MaoLin Ye e a Key Laboratory of Qinghai-Tibetan Plateau Environment and Resource (MOE), School of Life and Geographic Science, Qinghai Normal University, XiNing 810008, China b State Key Laboratory of Cryosphere Sciences, Cold and Arid Regions Environment and Engineering Research Institute, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China c Luminescence Dating Group, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, 18 XinNing Road, XiNing 810008, China d Graduate University of Chinese Academy of Sciences, Beijing 100049, China e Institute of Archaeology, Chinese Academy of Social Sciences, Beijing 100077, China article info abstract

Article history: The archaeological Lajia and Lamafeng sites were situated in the Guanting Basin in the northeastern edge Received 15 October 2011 of the Tibetan Plateau, and were in the second terrace of the Yellow River. The Lamafeng site is only Received in revised form 1500 m away from Lajia site. The Lajia site belongs to typical Qijia culture (4100e3600 cal a BP). Many 23 February 2012 human skeletons were found in the Lajia site. These remains presented a state of unnatural deaths. They Accepted 25 February 2012 were all buried in-situ. The Lajia site recorded a prehistoric natural disaster, and the cause of which was Available online 7 March 2012 probably a combination of earthquake and flooding due to the outburst of a lake that had been dammed by a landslide on the Yellow River. The Lajia site was abandoned by the prehistoric people after the Keywords: OSL dating disaster, but follow-up cultural relics were not found. Lamafeng site is a representative of Xindian Culture e Radiocarbon dating (3400 2600 cal a BP). The investigation of the Xindian Culture is intensive. However, the chronological Lajia and Lamafeng archaeological sites data is still very limited, and no luminescence data has been reported so far. In the current study, both Qijia and Xindian Cultures optically stimulated luminescence (OSL) (three samples) and accelerator mass spectrometry (AMS) (five NE Tibetan Plateau charcoal samples) dating are applied to samples from Lamafeng archaeological site. The results showed that: (1) For the sample from the cultural layer, within error margins OSL and 14C ages are in good agreement. The 14C ages show that the cultural layer has an age range of w2400e2300 cal a BP. (2) The Lamafeng site was inhabited by the people of Xindian Culture, which indicated that the natural disaster occurred in the Qijia culture period did not completely destroy the prehistoric culture in the basin. (3) There was an enhanced extreme flood activity during Qijia and Xindian Culture periods, and the extreme flood period was ended at 2.6 0.2 ka. http://ir.isl.ac.cnÓ 2012 Elsevier B.V. All rights reserved.

1. Introduction (35510N, 102480E) is located within the fluvial sediments of the second river terrace above the Yellow River. The excavation of the There are many prehistoric sites distributed in the Guangting Lajia site started in 1999, and revealed a number of surprising Basin in Qinghai Province covering the time period from 6000 cal discoveries (Institute of Archaeology, Chinese Academy of Social a BP to 2600 cal a BP, including Yangshao culture (6000e5000 cal Sciences & Qinghai Provincial Institute of Cultural Relics and a BP), Majiayao culture (5000e4000 cal a BP), Qijia culture (ca Archaeology, 2002). More than twenty human skeletons were 4100e3600 cal a BP), and Xindian Culture (3400e2600 cal a BP) found within an area of about 100 square metres. In a house of about (State Cultural Relics Bureau, 1996). There are two archaeological 15 square metres there were fourteen skeletons, which presented sites close to each other in the Guanting Basin (Fig. 1). One is Lajia a state of unnatural deaths. They were all buried in-situ. The Lajia occupied during the Qijia period, and the other is Lamafeng, occu- site recorded a prehistoric natural disaster, whose reason was pied during the Xindian Culture period. The Lajia archaeological site thought to be a combination of earthquake, debris flow, and Yellow River floodings resulted from climate changes (Xia and Yang, 2003), or the outburst of a lake that had been dammed by a landslide on * Corresponding author. State Key Laboratory of Cryosphere Sciences, Cold and the Yellow River triggered by a strong earthquake (Wu et al., 2009). Arid Regions Environment and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China. The world oldest millet noodle was found at this site, which was E-mail addresses: [email protected], [email protected] (Z. Lai). covered by a bowl when the disaster occurred, whose age

1871-1014/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.quageo.2012.02.024 G. Hou et al. / Quaternary Geochronology 10 (2012) 394e398 395 represents the time of the disaster. It was dated by 14C accelerator 360 mm with w70% of precipitation during summer. The basin mass spectrometry (AMS) at 4000 cal a BP (Lu et al., 2005). elevation is 1754e1906 m. The Lamafeng section (355103900N, The Lajia site was abandoned by the prehistoric people after the 1024805700,elevation1791m,Fig.1b) is exposed in a naturally eroded disaster. It was re-inhabitated ca. 600 years later by the people of gully slope, and has a thickness of 400 cm (Fig. 2a). From the top to the Xindian Culture at the Lamafeng site (Xie, 2002), which is situated bottom, it consists of soil (0e310 cm), cultural layer (310e335 cm), 1500 m to the east of Lajia. Because the distance between the two and ﬂuvial deposit (>335 cm). The cultural layer is rich in black sites is very close, we can regard them as a whole. Lamafeng site is organic matter, charcoals, animal bones, and some pottery pieces. The a representative of Xindian Culture and is located in the center of pottery shards indicate that they belong to the Xindian Culture. the Guanting Basin. Xindian Culture is the successor of Qijia culture, The soil layer is in dark colour, with some organic matter and and radiocarbon ages (only six in total by far) on charcoal associ- apparent mycelia and worm hole. Fluvial deposit belongs to the ated with slags range from about 3400 cal a BP to about 2600 cal sedimentary characteristic of slackwater deposits (Yang et al., aBP(Xie, 2002). However, the chronological data is still very limited and no luminescence ages have been reported so far. In this study, both optically stimulated luminescence (OSL) dating and radiocarbon dating will be used to provide more absolute age control for the Lamafeng site. The implications for archaeology and environment will be discussed.

2. Study area, section and samples

The Guanting Basin is in the northeastern edge of the Tibetan Plateau (Fig. 1a). It is surrounded by the Laji Mountains to the north- west, and the Jishi-Mountains to the south. The Yellow River runs in the southern part of the basin from west to east. The basin has an annual average temperature of 8.6 C, and an annual precipitation of

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Fig. 1. (a) DEM (Digital Elevation Model) image of the Qinghai-Tibetan Plateau (QTP), with the Guanting Basin (black dot) in the northeastern edge, in between the cities of Lanzhou and Xining. (b) Locations of the archaeological sites of Lajia and Lamafeng in the Guanting Basin. The numbers show the sites of different cultures. Yangshao culture: 3, 5, 20; Majiayao culture: 2, 4, 6, 8, 9, 12; Qijia culture: 1, 3, 5, 7, 8, 9, 10, 11, 12, 13, 14, 18; Xindian Culture: 4, 6, 9, 15, 16, 17, 19 (State Cultural Relics Bureau, 1996; Yang Fig. 2. Pictures showing the sections (a), and the locations of samples and their et al., 2004). ages (b). 396 G. Hou et al. / Quaternary Geochronology 10 (2012) 394e398

2500 size of 0.5 0.5 0.5 cm in volume. It is in a block with some a angles, suggesting that the charcoal is buried in-situ. N 2000 3. Sample preparation and measurements 14.5 Gy 0 Gy In the luminescence laboratory, the 38e63 mm quartz grains 1500 were extracted following the procedures described by Lai (2010). Laboratory preparation included treatment with HCl (10%) and H2O2 (30%) to remove carbonates and organics, respectively. The m 1000 grain size of 38e63 m fraction was isolated by sieving, and then was treated with H2SiF6 for about two weeks. Quartz purity was monitored by IR stimulation. Any samples with measurable IRSL signals were retreated with H2SiF6 to avoid De underestimation OSL intensity (c/0.16s) intensity OSL 500 (Aitken, 1998; Roberts, 2007; Lai and Brückner, 2008). Pure quartz samples were then fixed onto an area of about 0.6 cm diameter in 1.0 cm diameter stainless steel discs using silicone oil. The grains 0 are sparsely distributed and 4000e6000 grains could be mounted 012345in a disc with a diameter of 1 cm according to Duller (2008). stimulated time (s) OSL measurements were performed on an automated Risoe TL/ 2 OSL-DA-20 reader. Stimulation was by blue LEDs (with emission b band of 470 20 nm) for 40 s at 130 C, and detection was through a 7.5 mm Hoya U-340 filter. Preheat was using 260 C for 10 s, and cut-heat at 220 C for 10 s. OSL signals from the first 0.64 s stimulation were integrated for growth curve construction after back- ground subtraction (using the last 8 s stimulation in the shine- down curve). Water content was taken as 7 5% for all samples, as the study area is a semi-arid region. The concentrations of U, Th, 1 and K were measured by neutron activation analysis (NAA). The Lx/Tx alpha efficiency for 38e63 mm fraction quartz was taken as 0.035 0.003 (Lai et al., 2008). The cosmic ray dose rate was estimated for each sample as a function of depth, altitude and geomagnetic latitude (Prescott and Hutton, 1994). Five charcoal samples were analysed in Peking University in China. The comparisons of 14C dates with luminescence ages have 0 to be based on the calibrated radiocarbon ages (years cal BP), and 14 01020the calibration of the C dates was performed using the program ‘Calpal-2007’ (Weninger et al., 2007). Dose (Gy)

4. De determination Fig. 3. OSL characteristics for sample EF1-OSL2. (a) The OSL shine-down curves. (b) Growth curves of six individual aliquots and their average growth curve (the red line with empty circles). The error bar is smaller than the symbol for the empty circles. (For A combination of the single aliquot regenerative-dose (SAR) interpretation of the references to colour in this figure legend, the reader is referred to (Murray and Wintle, 2000) and the standardized growth curve the web version of this article.) (SGC) (Roberts and Duller, 2004; Lai, 2006; Lai et al., 2007) technique was employed. Six aliquots were used for each individual http://ir.isl.ac.cnsample for De determination using SAR. An SGC was then con- 2005). It is reddish brown clay deposition, and has obvious hori- structed for each sample using the SAR data. Then for each sample zontal bedding. 12e18 aliquots were measured for OSL of N and test dose, and the Three OSL samples (EF1-OSL1, EF1-OSL2, and EF1-OSL3) and five test dose corrected OSL signal (LN/TN) was then matched with the 14 AMS C dating samples (EF1-G, EF2-A, EF2-B, EF2-C, and EF2-D) SGC to obtain a De value. The final De value for each sample is the were collected from the section (Fig. 2b). Sample EF1-OSL1 was mean of all De values (by both SAR and SGC) of all aliquots. collected from the upper part of the section just above the cultural Fig. 3 shows OSL decay curves for sample EF1-OSL2, as well as layer, EF1-OSL2 from the cultural layer, and sample EF1-OSL3 from growth curves of the six aliquots. The OSL signal decreases very the fluvial deposits. All the five charcoal 14C samples were obtained quickly during the first second of the stimulation, showing that it is from the cultural layer. Each piece of the charcoal has a minimum dominated by a fast component. The decay curve of 0 Gy

Table 1 OSL dating results of Lamafeng site in the Guanting Basin.

Sample ID N Sedimentary types U (ppm) Th (ppm) K (%) W (%) Dose rate SAR De (Gy) SGC De (Gy) Final De (Gy) Age (ka) and depth (m) (Gy/ka) EF1-OSL1 12aþ6b Fossil soil (2.8) 2.33 0.19 10.37 0.28 1.44 0.07 7 5 2.93 0.21 8.1 0.46 7.9 0.31 7.95 0.24 2.7 0.2 EF1-OSL2 12aþ6b Cultural layer (3.2) 2.54 0.17 8.40 0.24 1.50 0.08 7 5 2.88 0.21 7.7 0.2 7.3 0.08 7.46 0.1 2.6 0.2 EF1-OSL3 6b Fluvial deposit (3.6) 2.44 0.18 9.31 0.26 1.61 0.08 7 5 3.02 0.22 50.0 5.1 50.0 5.1 16.6 2.1

a Aliquot numbers using SGC method. b Aliquot numbers using SAR method. G. Hou et al. / Quaternary Geochronology 10 (2012) 394e398 397 regeneration dose shows negligible thermal transfer. The shapes of Table 3 the six growth curves of the six aliquots are similar, showing the Comprehensive chronology. applicability of SGC technique. Dated object Age Data source Culture Xindian Culture 3.4e2.6 cal ka BP Xie (2002) type Qijia Culture 4.1e3.6 cal ka BP Xie (2002) 5. Results and discussions Majiayao Culture 5e4 cal ka BP Xie (2002) Yangshao Culture 6e5 cal ka BP Xie (2002) Disasters On the top of the 2685 50 cal a BP Yang et al. 5.1. OSL and AMS 14C dating results time slackwater sediments (2005) at the Lamafeng sites 14 The OSL dating results are listed in Table 1, and the C dating Flooding from late 3.8e2.7 cal ka BP Yang et al. results in Table 2. The three OSL ages are in stratigraphic order Qijia to mid-late (2005) within error. The five AMS 14C dating results are consistent within Xindian Culture e period a range of 2426 2288 cal a BP, with an average age of 2300 cal a BP. Two age sample 3678 74 cal a BP Xia and Yang The OSL ages of samples EF1-OSL1 and EF1-OSL2 are 2.7 0.2 and from beneath the 3875 70 cal a BP (2003) 2.6 0.2 ka, respectively, which are similar within error. Sample EF- slackwater sediments OSL1 was collected from the soil just above the cultural layer, and its at the Lajia site Earthquakes, flooding Ca. 4 cal ka BP Yang et al. (2003) age represents the maximum age of the inhabitation in the site. Author’ Archaeological layer 2.4e2.3 cal ka BP This manuscript Sample EF-OSL2 was collected from the cultural layer. The two experimental of Xindian Culture similar OSL ages show that the inhabitation in this site was not long. data period Within error the 14C ages (on charcoal from the cultural layer) are in Archaeological layer Ca. 2.6 ka This manuscript agreement with the OSL age of sample EF1-OSL2. According to the of Xindian Culture 14 period six previously published AMS C ages, the Xindian Culture periods “Fossil soil” in fluvial Ca. 2.7 ka This manuscript were 3400e2600 cal a BP (Xie, 2002). As a result, we can infer that deposits above the cultural layer of EF1 section belongs to late Xindian Culture. archaeological layer

fl 5.2. Prehistorical cultures in the Guanting Basin 5.3. The ages of ood period fl The Guanting Basin suffered from large-scale earthquakes and Some studies reported a period of enhanced palaeo ood activ- floods at about 4000 cal a BP, which caused severe damage to the ities during the Holocene that were recorded in a site of overbank Qijia Culture (Yang et al., 2003). Did the culture in the Guanting slackwater sediments found on the river terrace in the Guanting fl Basin cease after such tremendous natural disaster? According to Basin, The slackwater deposits show at least 14 extreme ood the archaeological survey in the Guanting Basin, the Yangshao events (Xia and Yang, 2003; Yang et al., 2004). Two samples from culture (6000e5000 cal a BP) sequenced to the Xindian Culture late Qijia pits immediately beneath the slackwater sediments at the (3400e2600 cal a BP) (Institute of Archaeology, Chinese Academy Lajia site yielded radiocarbon ages of 3678 74 cal a BP and of Social Sciences & Qinghai Provincial Institute of Cultural Relics 3875 70 cal a BP (Xia and Yang, 2003), suggesting the start of the fl and Archaeology, 2002). There are only 3 Yangshao culture sites. uvial deposit. Settlements of the mid-late Xindian sites have been However, there are 7 Majiayao cultural (5000e4000 cal a BP) sites, found on the top of the slackwater sediments, and the radiocarbon fi 12 Qijia cultural sites in 4100e3600 cal a BP, and 7 Xindian Culture dating of a single piece of animal bone in a securely strati ed (3400e2600 cal a BP) sites in the basin (Fig. 1b). Therefore, the archaeological context provided a radiocarbon date of prehistoric residence seemed to be sequenced from 6000 cal a BP to 2685 50 cal a BP (Yang et al., 2005). This has been treated as the 2600 cal a BP. A compilation of chronological data for cultures in the upper age limit for the end of the slackwater deposits (Yang et al., fl study area was listed in Table 3. 2005). As a result, there was an enhanced ood activity during e In Lajia, the follow-up culture after Qijia culture has not been 3800 2700 cal a BP in the basin. fl discovered yet. It is possible that the Lajia site was abandoned In the Lamafeng site, the uppermost uvial deposit was imme- http://ir.isl.ac.cndiately below the cultural layer (with an OSL age of 2600 200 a), because of a series of natural disasters during the Qijia culture fl period. However, at higher elevations of the basin, there are some and no uvial deposit was observed above the archaeological layer. fi fl Qijia culture sites. We speculate that these sites are less affected by Hence, the nal ood should be older than ca 2600 years, in the floods. Moreover, in the northeastern edge of the Tibetan agreement with previous results. Plateau, Xindian Culture is the inheritance and development of It is worth noting that the age of OSL sample EF1-OSL3 is fl Qijia culture, and the residents of both cultures are similar. (Xie, 16.6 2.1 ka. The sample was collected from a uvial layer, which is 2002; Qinghai Provincial Institute of Cultural Relics and widely distributed in the second terrace of the basin. The age of e Archaeology, 2004). slackwater deposits is 3800 2700 cal a BP (Xia and Yang, 2003; Yang et al., 2005), so the age of EF1-OSL3 is obviously too old. It could be caused by insufficient bleaching.

Table 2 14 Comparing OSL and AMS C dating results in the Lamafeng site. 6. Conclusions AMS 14C dating OSL dating

14 In the current study, three OSL samples and ﬁve charcoal AMS Sample ID AMS C dating Calendar year age Sample ID Ages (ka) 14 (a BP) (cal a BP) C samples were collected from the Lamafeng archaeological site EF1-G 2335 25 2401 6 EF1-OSL2 2.6 0.22 in the Guanting Basin. The results showed that: (1) The OSL age of 14 EF2-A 2265 30 2317 65 2.6 0.2 ka is in good agreement with the C ages from the EF2-B 2210 30 2288 61 cultural layer which cover an age range 2400e2300 cal BP. (2) The EF2-C 2285 35 2325 66 Lajia site was abandoned by the prehistoric people after the EF2-D 2225 25 2296 61 disaster, and then was re-inhabited in the Lamafeng site during the 398 G. Hou et al. / Quaternary Geochronology 10 (2012) 394e398

Xindian Culture. (3) The last extreme flood was older than Lai, Z.P., Zöller, L., Fuchs, M., Brückner, H., 2008. Alpha efficiency determination for 2.6 0.2 ka in the study site. OSL of quartz extracted from Chinese loess. Radiation Measurements 43, 767e770. Lu, H.Y., Yang, X.Y., Ye, M.L., Liu, K.B., Xia, Z.K., X.Y, Cai, L.H., Wu, N.Q., Liu, D.S., 2005. Acknowledgements Millet noodles in Late Neolithic China. Nature 437, 967e968. Murray, A.S., Wintle, A.G., 2000. Luminescence dating of quartz using an improved single-aliquot regenerative-dose protocol. Radiation Measurements 32, 57e73. This work was supported by China Geological Survey Prescott, J.R., Hutton, J.T., 1994. Cosmic ray contribution to dose rates for lumines- (1212011120046), the China NSF (grants 41161018, 41172168, cence and ESR dating: large depths and long-term time variations. Radiation 41121001), the One Hundred Talent Project of the Chinese Academy Measurements 23, 497e500. Qinghai Provincial Institute of Cultural Relics and Archaeology, 2004. The Pre- of Sciences granted to ZPL (A0961), and the Application basic historical Graveyard of Minhe County Hetaozhuang Village. Science Press, research plan of Qinghai Science & Technology Department (grant Beijing, pp. 156e168 (in Chinese). 2011-Z-744). Roberts, R.M., 2007. Assessing the effectiveness of the double-SAR protocol in isolating a luminescence signal dominated by quartz. Radiation Measurements Editorial handling by: F. Preusser 42, 1627e1636. Roberts, H.M., Duller, G.A.T., 2004. Standardised growth curves for optical dating of References sediment using multiple-grain aliquots. Radiation Measurements 38, 241e252. State Cultural Relics Bureau, 1996. The Culture Relic Atlas of China: Qinghai Branch. Aitken, M.J., 1998. An Introduction to Optical Dating. Oxford University Press, China Map Press, Beijing, pp. 15e23. (in Chinese with English abstract). Oxford. Weninger, B., Joris, O., Danzeglocke, U., 2007. CalPal-2007. Cologne Radiocarbon Duller, G.A.T., 2008. Single-grain optical dating of Quaternary sediments: why Calibration & Palaeoclimate Research Package. http://www.calpal.de. aliquot size matters in luminescence dating. Boreas 10, 589e612. Wu, Q.L., Zhang, P.Z., Zhang, H.P., Ye, M.L., Zhang, Z.Q., 2009. A palaeo-earthquke Institute of Archaeology, Chinese Academy of Social Sciences & Qinghai Provincial induced damming and bursting ofYellow River and the abnormal flood that Institute of Cultural Relics and Archaeology, 2002. Excavation of the prehistoric destroyed Lajia relic. Science in China Series-D-Earth Sciences 8, 114e1159 (in Lajia site in Minhe, Qinghai. Archaeology 12, 12e25 (in Chinese with English Chinese with English abstract). abstract). Xia, Z.K., Yang, X.Y., 2003. Preliminary study on the flood events about 4 ka BP in Lai, Z.P., 2006. Testing the use of an OSL standardized growth curve (SGC) for De north China. Quaternaty Sciences 23, 667e674 (in Chinese with English determination on quartz from the Chinese Loess Plateau. Radiation Measure- abstract). ments 41, 9e16. Xie, D.J., 2002. Pre-historical Archaeology of Gansu and Qinghai Provinces. Cultural Lai, Z.P., 2010. Chronology and the upper dating limit for loess samples from Luo- Relices Press, Beijing, pp. 170e184. (in Chinese with English abstract). chuan section in Chinese Loess Plateau using quartz OSL SAR protocol. Journal Yang, X.Y., Xia, Z.K., Ye, M.L., 2003. Prehistoric disasters at Lajia Site, Qinghai, China. of Asian Earth Sciences 37, 176e185. Chinese Science Bulletin 48, 1877e1881 (in Chinese). Lai, Z.P., Brückner, H., 2008. Effects of feldspar contamination on equivalent dose Yang, X.Y., Xia, Z.K., Cui, Z.J., Ye, M.L., 2004. Environmental setting of Archaeological and the shape of growth curve for OSL of silt-sized quartz extracted from sites depositional process and distribution at Guanting basin. Acta Geogrphica Chinese loess. Geochronometria 30, 49e53. Sinica 59, 455e461 (in Chinese ). Lai, Z.P., Brückner, H., Zöller, L., Fülling, A., 2007. Existence of a common growth Yang, X.Y., Xia, Z.K., Cui, Z.J., 2005. Holocene extreme floods and its sedmentary curve for silt-sized quartz OSL of loess from different continents. Radiation characteristic in the upper reaches of the Yellow river. Quaternary Sciences 25, Measurements 42, 1432e1440. 80e85 (in Chinese with English abstract).

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