Over 2000 palaeolithic sites, most of which were buried in loess deposits, have been discovered in China (
Journal of Geographical Sciences, Volume. 30, Issue 9, 1436(2020)
Luminescence dating of reticulated red clay buried in Lanshanmiao Paleolithic site in Zhejiang Province, southern China
The Lanshanmiao (LSM) Palaeolithic site, which was excavated in the summer of 2017 by the Zhejiang Provincial Institute of Cultural Relics and Archaeology, is the only excavated palaeolithic site in central Zhejiang Province to date. Luminescence dating methods, including optical stimulated luminescence (OSL) and thermal transfer OSL (TT-OSL) for quartz and post-infrared (IR) stimulated luminescence (pIRIR290) for feldspar, were used to determine the age of the LSM site. The results showed that the LSM section developed before 145.5 ± 12.5 ka and ended after 17.1 ± 1.0 ka. The TT-OSL dating of samples NJU2576 and NJU2615 showed that palaeolithic artifact-bearing layer was between 150 and 100 ka in age. The age range of the palaeolithic layer mainly corresponded to the transition between Marine Isotope Stage (MIS) 6 and MIS5. Our study showed that hominins prominently occupied the LSM site during the glacial and interglacial stages, when it exhibited a floodplain environment.
1 Introduction
Over 2000 palaeolithic sites, most of which were buried in loess deposits, have been discovered in China (
As excavation in the lower reaches of the Yangtze River has expanded, palaeolithic sites buried in Quaternary reticulated red clay have been increasingly unearthed; these discoveries aid the study of the evolution of palaeolithic culture in this area. Quaternary reticulated red clay is widely distributed in the lower reaches of the Yangtze River and is sensitive to the East Asian monsoon (
Earlier studies provided an ambiguous chronological framework for the Quaternary reticulated red clay in the middle-lower drainage of the Yangtze River, suggesting that the clay mainly developed during the Middle Pleistocene. The lower boundary age of the reticulated red clay is 1-1.2 Ma, as estimated by palaeomagnetic and stratigraphic correlations (
Luminescence dating is a robust Quaternary dating method and has been widely used in dating Chinese palaeolithic archaeological sites (e.g.,
2 Geographic, stratigraphic, and archaeological investigations
The LSM Palaeolithic site is located in the west Shengzhou Basin, 3.5 km southwest of the Chongren County (120°41'37″E, 29°34'37″N;
Figure 1.
The field excavation was conducted by the Zhejiang Provincial Institute of Cultural Relics and Archaeology in the summer of 2017 (
Figure 2.
More than 60 palaeolithic artifacts were unearthed from a 60 m² trench. The relics mostly included broken pieces, with several flakes and cores (
3 Luminescence dating
3.1 Sampling, laboratory measurement, and protocols
We inserted a metal tube in the cleaned loess section and obtained six samples at the LSM site for luminescence dating (
The sample preparation for equivalent dose (De) determination was conducted under dim red light in the laboratory. The two ends of the sample (~2-3 cm) that might have been exposed to sunlight were removed to ascertain the environmental dose rate and water content. The rest of the sample was treated with 30% H2O2 and 10% HCl to remove organic matter and carbonates. Then, the 40-63 and 63-90 µm size fractions were separated by wet sieving. The 40-63 µm particles were used for quartz extraction and were immersed in 40% H2SiF6 for two weeks to remove feldspar and then cleaned by using 10% HCl for 40 min. The purity of the isolated quartz was checked by the OSL IR depletion ratio method (
All luminescence measurements were performed on a Risø TL/OSL reader (model DA-20) equipped with an accurately calibrated 90Sr/90Y beta source at the Luminescence Laboratory of Nanjing University. Blue light-emitting diodes (LEDs; 470 nm, ~80 m W.cm-2) were employed for quartz stimulation, whereas IR LEDs (870 nm, ~135 m W.cm-2) were utilized to stimulate the feldspar (
Given the upper limit of dating, three methods were used to determine De: the single-aliquot regenerative-dose (SAR) protocol for quartz OSL dating, thermal transfer OSL (TT-OSL) and feldspar pIRIR290. The OSL dating method was validated for dating young sediments (
3.2 Results
NJU2572, NJU2574, and NJU2578 were measured by quartz OSL. The quartz samples generated a bright and fast-decaying natural OSL signal (Figures 3a and 3b). The decay curves of NJU2572 and NJU2574 quickly decreased to near zero in the initial 1.28 s stimulation. These results suggest that our samples were dominated by the fast component. The recycling ratio and recuperation of the two samples ranged from 0.94 to 1 and 0% to 0.1%, respectively, consistent with the criteria of acceptance. The dose-response curve (DRC) was fitted using a single exponential function. The DRC of NJU2572 fit well and showed linear growth, implying that the signals were far from saturation. However, the signals of NJU2574 and NJU2578 were saturated. As revealed in
Figure 3.
All samples were measured by TT-OSL to determine their De values. The inset indicates that the TT-OSL signal of NJU2574 decayed quickly and was dominated by the fast components (
Figure 4.
The pIRIR290 protocol was also used for all samples, but the De value was obtained for NJU2578 at 2.75 m depth and for NJU2615 at the bottom of the LSM section. The pIRIR signals for NJU2572, NJU2574, NJU2576, and NJU2577 were dim and dispersed. A total of 21 aliquots were tested for two samples (11 aliquots for NJU2578 and 10 for NJU2615). Five aliquots of NJU2578 and four aliquots of NJU2615 were rejected after examining the recycling ratio and recuperation results. As illustrated in Figures 4a and 4b, the IRSL signal of NJU2615 was brighter than its TT-OSL counterpart. The DRC of NJU2615 continually increased up to 600 Gy, which also indicated its dating potential. The De values ascertained using feldspar from NJU2578 (
3.3 Magnetic susceptibility and dose rate
The magnetic susceptibility of the LSM profile decreased with depth (
Figure 5.
Earlier studies on red clays in South China indicated that weathering eluviation causes the enrichment of U, which results in overestimations of the dose rate (
Dating results of quartz OSL, TT-OSL, and feldspar pIRIR290 dating methods
Dating results of quartz OSL, TT-OSL, and feldspar pIRIR290 dating methods
|
4 Discussion
4.1 Chronological sequence
The ages obtained from the quartz OSL, TT-OSL, and feldspar pIRIR290 dating methods increased with depth (
In summary, the samples dated from 145.5 ± 12.5 ka to 17.1 ± 1.0 ka, and the ages extended from the Late-Middle Pleistocene to the Late-Late Pleistocene. According to the OSL and TT-OSL ages of NJU2574, the upper age limit of the reticulated clay layer is approximately 94-102 ka, which indicates that the boundary of the Quaternary reticulated red clay formed in the Early-Late Pleistocene. The cultural layer was deposited between 150 and 100 ka, during the Late-Middle Pleistocene.
4.2 Correlation with QLT and YDG palaeolithic sites
Most palaeolithic industries in Zhejiang Province belonged to the southern main industry, which was characterized by direct hammer percussion methods and simple tools made of pebbles and large pieces, such as those found in the QLT (
The miniaturisation of stone artifacts at the YDG site is evidently similar to the conditions observed at the LSM site. Stone artifacts at the LSM site also consisted of flint. However, bipolar techniques were only applied at the YDG sites, whereas the hammer percussion technique was used only at the QLT and LSM sites. The LSM site was in the same age range as the upper cultural layer of the QLT site. Therefore, the LSM site can be regarded as a supplementary material for the Middle to Late Palaeolithic industry in Zhejiang Province during the late stage of the Middle Pleistocene to Late Pleistocene. Our detailed luminescence dating results are essential for setting the chronological sequence of palaeolithic industry in Zhejiang Province.
4.3 Environmental implication
Pebbles and breccia coexisted with the artifacts and disappeared at approximately 1.75 m on the LSM section (top of Layer 3) (
The age range of LSM site mainly corresponded to transition from MIS6 to MIS5, thereby implying that hominins lived in both glacial and interglacial stages. For the relatively steady glacial period, pollen analyses of Late Quaternary boreholes in the Yangtze River Delta (
Figure 6.
The age range of LSM site mainly corresponded to transition from MIS6 to MIS5, thereby implying that hominins lived in both glacial and interglacial stages. For the relatively steady glacial period, pollen analyses of Late Quaternary boreholes in the Yangtze River Delta (
5 Conclusion
This study indicated that multiple protocols of luminescence dating methods, namely, OSL, TT-OSL, and pIRIR290, are applicable for the LSM palaeolithic site, which is buried by reticulated clay. The results showed that the LSM section developed before 145.5 ± 12.5 ka and ended after 17.1 ± 1.0 ka. The OSL and TT-OSL ages of NJU2574 ranged from 94 to 96.8 ± 5.4 ka and provide a possible absolute age of approximately 94-100 ka for the upper boundary of the reticulated red earth. This finding also proves that the reticulated red clay in this area developed in the Late Pleistocene. The feldspar ages of the lower two samples were disregarded due to their poor luminescence performances. Based on the TT-OSL ages, the artifact assemblages buried entirely in the reticulated red clay dated to approximately 150 to 100 ka and corresponded to stage of transition between MIS6 and MIS5. The luminescence dating results confirmed the presence of hominin activity in the glacial period at the late stage of the Middle Pleistocene in southern China. An independent chronological reference was added for further study of the evolution of palaeolithic industry in Zhejiang Province.
[1] et alMagnetostratigraphic dates of Lantian Homo erectus. Acta Anthropologica Sinica, 9, 1-7(1990).
[4] et alWoody cover and hominin environments in the past 6 million years. Nature, 476, 51-56(2011).
[5] The study on uranium-series dating of fossil bones and absolute age sequence for the main Paleolithic sites of North China. Acta Anthropologica Sinica, 3, 259-269(1984).
[9] Seventy years of exploration: A review and prospect of Paleolithic archaeology in China. China Cultural Relics News(2019).
[10] Dose-rate conversion factors: Update. Ancient TL, 29, 5-8(2011).
[12] et alA brief report on Paleolithic archaeological survey of Deqing in 2016. Cultural Relics of the East, 1-5(2016).
[15] et alThe top boundary age of the reticulated layer in Binshaling area of Poyang Lake. Scientia Geographica Sinica, 32, 110-115(2012).
[17] Luminescence signals from polymineral fine-grains in strongly chemically-weathered sediments from a paleolithic site and their usefulness for dating. Quaternary Science, 39, 438-447(2019).
[18] The change of natural zones and the evolution of red earth in China. Acta Geographica Sinica, 54, 193-203(1999).
[19] The K content of the K-feldspars being measured in optical dating or in thermoluminescence dating. Ancient TL, 15, 11-13(1997).
[21] Comparison and primarily interpretation of magnetic susceptibilities in different sediments. Acta Geoscientica Sinica, 28, 541-549(2007).
[25] Advances in chronological research of magnetic strata in southern China. Frontiers in Earth Sciences, 18, 158-170(2011).
[26] et alMagnetostratigraphy of the Qiliting section (SE China) and its implication for geochronology of the red soil sequences in southern China. Geophysical Journal International, 1, 107-117(2008).
[27] . 1985. Loess and the Environment..
[29] et alA preliminary survey on loess deposit in Eastern Qinling Mountains (Central China) and its implication for estimating age of the Pleistocene lithic artifacts. Quaternary Science, 27, 559-567(2007).
[31] et alEarth surface processes and their effects on human behavior in monsoonal China during the Pleistocene-Holocene epochs. Journal of Geographical Sciences, 27, 33-46(2017).
[39] et alOptically stimulated luminescence ages for human occupation during the penultimate glaciation in the western Loess Plateau of China,. Journal of Quaternary Science, 31, 928-935(2016).
[40] Optical stimulated luminescence dating of terrestrial sediments in the Nihewan basin and its implication for the evolution of ancient Nihewan lake. Quaternary Research, 33, 403-414(2013).
[42] Study on magnetic stratigraphy of wind-dust accumulation-soil sequence in southern Anhui and its paleoenvironmental significance. Chinese Science Bulletin, 48, 1465-1469(2003).
[43] Optically stimulated dating of upper part of a thick loess section at Caoxian near the northern desert of China. Quaternary Science, 27, 546-552(2007).
[47] et alA modified depositional hypothesis of the Hanjiang loess in the southern Qinling Mountains, Central China. Progress in Physical Geography: Earth and Environment, 41, 775-787(2017).
[58] Taphonomic and paleoenvironmental issues of the Pleistocene loessic Paleolithic sites in the Qinling Mountains, central China. Science China Earth Sciences, 46, 881-890(2016).
[59] et alPaleolithic tools and their dating in newly discovered loess layers in Lantian, Shaanxi. Science Bulletin, 59, 1318-1326(2014).
[60] et alPaleolithic and loess deposits found in the middle reaches of the Nanluo River in the East Qinling Mountains. Quaternary Research, 28, 988-999(2008).
[61] Lithic artefacts collected from open-air sites during 1995-1999 investigations in Luonan basin, China. Acta Anthropologica Sinica, 24, 87-103(2005).
[68] The weathering sequence of the red earth over southern China. Journal of Mountain Science, 18, 7-12(2000).
[69] A review of Paleolithic archaeology in Zhejiang. Southeast Culture, 6-10(2008).
[71] Loess research and paleolithic archeology. Quaternary Research, 25, 461-466(2005).
[73] Reticulated laterite in southern China and the unusually strong period of the East Asian monsoon. Science Bulletin, 51, 186-193(2006).
[77] The luminescence chronology of the “old red sand” in Jinjiang, Fujian, and its significance for the lunar dating of Quaternary sediments in the south. Science Bulletin, 52, 2646-2654(2007).
[78] Review of the post-IR IRSL dating protocols of K-feldspar. Methods and Protocol, 3(1): 10.3390/mps3010007.(2020).
[79] et alComparison of geochemical characteristics between the Basaltic red clay and Quaternary red clay in Hainan. Chinese Journal of Soil Science, 49, 1009-1014(2018).
[80] Investigation report of Paleolithic in Zhejiang Province. Journal of Anthropology, 22, 105-119(2003).
[82] . Changxing County Cultural Relics Protection and Management Office. Qiliting and Yingdinggang..
[83] et alMagnetic susceptibility characteristics and paleoenvironment records of laterite in the Lushan JL profile. Mountain Journal, 29, 385-394(2011).
[84] et alResearch on laterite deposition and environmental change in southern China. Journal of Zhejiang Normal University (Natural Science Edition), 28, 206-210(2005).
Get Citation
Copy Citation Text
Ying LU, Xuefeng SUN, Xinmin XU, Yalin LIU, Shuangwen YI. Luminescence dating of reticulated red clay buried in Lanshanmiao Paleolithic site in Zhejiang Province, southern China[J]. Journal of Geographical Sciences, 2020, 30(9): 1436
Category: Research Articles
Received: Mar. 6, 2020
Accepted: Jun. 2, 2020
Published Online: Apr. 21, 2021
The Author Email: SUN Xuefeng (xuefeng@nju.edu.cn)