Optically Stimulated Luminescence Dating of Aeolian Sediment Profiles in the Sandy Lands of Northeastern China Near the Edge of the Monsoon Zone and Its Paleoenvironmental Significance

HUANG Long¹, Gusiletu², ZHOU Caiting¹, YANG Xiayao¹, SI Yuejun¹, HUANG Rihui¹, HANG Xiaoju², NIU Dongfeng¹

¹School of Geographical Sciences, Lingnan Normal University, Zhanjiang, Guangdong, China
²Salawusu Archaeological Site Park Administration, Wushen Banner, Inner Mongolia, China

Abstract

The sandy lands of northeastern China, located near the edge of the East Asian monsoon zone, are highly sensitive to climate change, making them ideal for investigating the evolutionary history of regional aeolian processes. This study presents optically stimulated luminescence dating of aeolian sediments from two representative profiles situated near the edge of the Horqin Sandy Land (KE) and the Otindag Sandy Land (HS). By integrating sedimentary facies data from the two profiles with additional regional paleoenvironmental records, we reconstructed the regional aeolian evolution history and examined the factors influencing sand and paleosol formation.

The results revealed that: (1) The KE profile indicated the development of dark black sandy paleosols between about 9.8 and 3.0 ka, likely reflecting weak aeolian activity. In contrast, thick light gray sandy paleosols formed from around 0.2 ka, indicating intensified aeolian activity and continuous reworking of surface sediments, preventing older deposit formation. (2) In the HS profile, gray-yellow aeolian sand layers were deposited around 13.4 ka, 1.2–0.5 ka, and since 0.5 ka, indicating episodes of strong aeolian activity. Dark black sandy paleosols formed between about 11.6 and 1.9 ka, corresponding to a period of weaker aeolian activity. (3) Since about 13.4 ka, the region has undergone three stages of climatic and aeolian evolution: (i) a warming period from 13.4 ka to the early Holocene, associated with relatively strong aeolian activity; (ii) a warm and humid mid-Holocene, marked by reduced aeolian activity; and (iii) a late Holocene period of fluctuating cooling, during which aeolian activity increased again. (4) Variations in the timing of dark black sandy paleosol development between the KE and HS profiles, compared with records from the central parts of these sandy lands, suggest that regional topography and paleoclimatic differences may significantly influence aeolian sediment development.

Keywords: aeolian sedimentation; OSL dating; paleoenvironmental change; Horqin Sandy Land; Otindag Sandy Land

1. Study Area and Sample Collection

1.1 Overview of the Study Area

The Horqin and Otindag Sandy Lands are located in the monsoon marginal zone of northeastern China, where the ecological environment is relatively fragile and highly responsive to climate change. These regions have accumulated substantial aeolian deposits, making them ideal for paleoenvironmental research. Previous studies have demonstrated that the evolution of these sandy lands is jointly influenced by climate change and human activity. The Horqin Sandy Land, situated at the junction of Northeast and North China, covers parts of Bairin Right Banner, Ongniud Banner, Aohan Banner, Tongliao City, and Hinggan League, with a total area of approximately 2.38×10⁴ km². The region has a temperate continental monsoon climate, with an average annual precipitation of 400 mm and an average annual temperature of 6–7.5°C. The frost-free period lasts only 4–5 months, and the area experiences significant frost for 6–7.5 months annually.

The Otindag Sandy Land lies in the central Xilingol Grassland of Inner Mongolia, comprising parts of Xilingol League and Keshiketeng Banner in Chifeng City. It serves as the source area for the Xar Moron and Yiligin Rivers. The terrain slopes from southeast to northwest, with elevations decreasing from 1500 m in the southeast to 1000 m in the northwest. The region is also a typical monsoon marginal transition zone with a fragile ecological environment, characterized by arid and semi-arid climates. Annual precipitation ranges from 380 mm in the southeast to 140 mm in the northwest, with an average annual temperature of 3–5°C and a frost period lasting 6–7 months. Both sandy lands share similar climatic and environmental characteristics.

1.2 Sample Collection

Based on field investigations of the Horqin and Otindag Sandy Lands, we selected two typical aeolian sediment profiles located on high river valley slopes with similar climatic backgrounds but distinct latitudinal positions. The KE profile (43°48′59.27″N, 118°18′03.49″E) is situated in the western part of the Horqin Sandy Land, on the eastern side of the Chagan Moron River, a tributary of the Xar Moron River. This profile was exposed during road and railway construction and features a thick sequence of dark black sandy paleosols. Located far from the modern riverbed on high terrain, the profile exhibits a semi-circular shape due to geomorphic constraints, with aeolian deposits including sand layers and paleosols.

The HS profile (42°24′42.30″N, 116°54′16.31″E) is located in the southeastern Otindag Sandy Land, on the eastern side of the Chaogeduer River valley. Exposed during highway construction, this profile contains multiple aeolian sequences of sand and paleosols on a high hillside far from the modern riverbed. Systematic sampling was conducted at both sites, with priority given to the top and bottom of dark black sandy paleosol layers and at boundaries between different sedimentary layers. Stainless steel tubes (3 cm diameter) were inserted parallel to target strata, sealed with black plastic bags to prevent light exposure, and immediately sealed after extraction. Detailed sampling records and labels were maintained for laboratory analysis.

At the KE profile, three samples (KE-1 to KE-3) were collected from top to bottom, while five samples (HS-1 to HS-5) were obtained from the HS profile. Sampling depths and sediment characteristics are summarized in [TABLE:1].

2. OSL Dating of Samples

2.1 Sample Pretreatment

All pretreatment procedures were conducted under dim red light. The process involved: (1) collecting approximately 5 cm of sediment from both ends of each tube for environmental dose rate and water content measurements; (2) dividing the remaining sample into two portions for backup and analysis; (3) cleaning samples and treating them with 10% H₂O₂ and 30% HCl to remove organic matter and carbonates; (4) drying and sieving to isolate 90–125 μm grains; (5) separating quartz grains using sodium polytungstate heavy liquid (2.62 g/cm³); and (6) etching quartz grains with 40% HF for 40 minutes to remove feldspar impurities and the alpha-irradiated outer layer, followed by washing and drying.

2.2 OSL Dating Analysis

Equivalent doses were measured using a Risø TL/OSL DA-20 reader equipped with blue LED stimulation (470±30 nm) and Hoya U-340 filters. The single-aliquot regenerative-dose (SAR) protocol was employed, with 9.8 mm aliquots containing approximately 90–125 μm quartz grains. Each sample was measured using 24–36 aliquots. Preheat plateau tests were conducted on sample HS-3, showing stable equivalent dose values between 180–280°C, indicating minimal temperature effects. A preheat temperature of 240°C for 10 s and a cutheat of 200°C were selected for all samples. Dose recovery tests yielded ratios of 0.9–1.1, confirming reliable measurement procedures.

Samples exhibited typical aeolian OSL characteristics, including bright signals dominated by the fast component, linear dose-response curves near the origin, and natural dose points within optimal response intervals [FIGURE:3]. Equivalent dose distributions were concentrated and approximately normal, indicating relatively uniform bleaching prior to burial.

3. Results and Analysis

3.1 Chronological Framework

Eight samples were analyzed from the KE and HS profiles, all showing good OSL properties and reliable dating results. In the KE profile, the bottom sample (KE-3, 8.3 m depth) yielded an age of 9.8±0.6 ka, while the middle sample (KE-2, 4.3 m depth) gave 3.0±0.2 ka, indicating that dark black sandy paleosols developed between 9.8 and 3.0 ka. The surface sample (KE-1, 2.0 m depth) provided an age of 0.2±0.1 ka, suggesting recent deposition.

In the HS profile, the bottom gray-yellow sand layer (HS-5, 3.1 m depth) dated to 13.4±1.1 ka. The dark black sandy paleosol layer yielded ages of 11.6±1.1 ka at its base (HS-4, 2.6 m depth) and 1.9±0.1 ka at its top (HS-3, 1.7 m depth), indicating development between 11.6 and 1.9 ka. Two overlying light gray sandy paleosol layers provided ages of 1.2±0.1 ka (HS-2, 1.1 m depth) and 0.5±0.1 ka (HS-1, 0.6 m depth). The surface gray-yellow sand layer dated to 0.2±0.1 ka. Ages generally decrease upward in both profiles, consistent with stratigraphic principles [TABLE:2].

3.2 Regional Aeolian History

Environmental changes in northern China's sandy lands are primarily controlled by the East Asian monsoon system. Enhanced summer monsoon precipitation promotes vegetation growth and soil development, stabilizing dunes, whereas weakened monsoons lead to dune activation and deposition of gray-yellow sand layers. The dark black sandy paleosols in the KE profile (9.8–3.0 ka) likely reflect a warm, humid climate with weak aeolian activity, corresponding to the Holocene Climatic Optimum. This is supported by regional pollen records from Gonghai Lake indicating increased precipitation during this interval.

The cessation of paleosol development around 3.0 ka corresponds to decreasing solar radiation and weakening summer monsoon intensity, marking a transition toward cooler, drier conditions. The thick light gray sandy paleosols formed since 0.2 ka suggest intensified aeolian activity and continuous surface reworking, preventing the preservation of older deposits.

In the HS profile, the gray-yellow sand layer at 13.4 ka formed during the last deglaciation, a period of relatively dry, cold climate. The overlying dark black sandy paleosols (11.6–1.9 ka) indicate weakened aeolian activity during the warm, humid mid-Holocene. The subsequent deposition of light gray sandy paleosols (1.2–0.5 ka) and gray-yellow sand layers (since 0.5 ka) reflects enhanced aeolian activity during the late Holocene, possibly associated with the Little Ice Age.

Overall, the region has experienced three stages of climate and aeolian evolution since 13.4 ka: (1) a warming period from 13.4 ka to early Holocene with strong aeolian activity; (2) a warm, humid mid-Holocene with weak aeolian activity; and (3) a late Holocene period of fluctuating cooling with intensified aeolian activity [FIGURE:4].

3.3 Factors Influencing Profile Development

The timing of dark black sandy paleosol development differs significantly between the KE and HS profiles. The HS profile began developing paleosols earlier (11.6 ka) and ceased later (1.9 ka) than the KE profile (9.8–3.0 ka). These differences likely reflect local topographic and climatic controls on moisture availability. The HS profile is located in the core of the Greater Khingan Mountains, surrounded by mountains that block moisture transport from the southeast. However, its location in the southeastern part of the sandy land, closer to the ocean, may provide adequate moisture for earlier vegetation establishment and prolonged soil development.

In contrast, the KE profile is situated at the intersection of the Greater Khingan and Yan Mountains, where topography enhances uplift of moist air from the southeast. Its proximity to the ocean also provides abundant moisture, with annual precipitation reaching up to 500 mm—significantly higher than in central and western parts of the Otindag Sandy Land. This may explain why other profiles in the central Horqin Sandy Land show earlier paleosol initiation and later termination than the KE profile. Local topography, distance from the ocean, and hydrological conditions thus exert significant influence on aeolian sedimentation and paleosol development, even within the same sandy land system [FIGURE:5].

4. Conclusions

This study employed OSL dating to analyze two typical aeolian sediment profiles from the margins of the Horqin and Otindag Sandy Lands, yielding the following conclusions:

1. The KE profile developed dark black sandy paleosols between 9.8 and 3.0 ka, indicating weak aeolian activity. Since 0.2 ka, thick light gray sandy paleosols have formed, suggesting intensified aeolian activity and continuous surface reworking.

2. The HS profile deposited gray-yellow aeolian sand layers at 13.4 ka, 1.2–0.5 ka, and since 0.5 ka, indicating strong aeolian activity. Dark black sandy paleosols formed between 11.6 and 1.9 ka, corresponding to a period of reduced aeolian activity.

3. Since 13.4 ka, regional climate and aeolian evolution have undergone three stages: (i) a warming period from 13.4 ka to early Holocene with strong aeolian activity; (ii) a warm, humid mid-Holocene with weak aeolian activity; and (iii) a late Holocene period of fluctuating cooling with enhanced aeolian activity.

4. Differences in the timing of dark black sandy paleosol development between the KE and HS profiles likely reflect variations in local topography, climate, and moisture availability, which significantly influence aeolian sediment accumulation and paleosol formation.

References

[1] Liu T S, An Z S, Yuan B Y. Eolian process and dust mantle (loess) in China[J]. Quaternary Sciences, 1985, 6(1): 113-125.

[2] Xia Yumei. A study on the pollen analysis and paleoenvironment of loess stratigraphy in Mengshigou at the southern edge of Horqin Sandy Land[J]. Journal of Desert Research, 1989, 9(4): 22-29.

[3] Qiu Shanwen. Study on the formation and evolution of Horqin Sandy Land[J]. Scientia Geographica Sinica, 1989, 9(4): 317-328, 97.

[4] Li Sen, Sun Wu, Li Xiaoze, et al. Sedimentary characteristics and environmental evolution of Otindag land in Holocene[J]. Journal of Desert Research, 1995, 15(4): 323-331.

[5] Li Mingqi, Jin Heling, Zhang Hong, et al. Climate change revealed by magnetic susceptibility and organic matter during the Holocene in Hunshandak Desert[J]. Acta Sedimentologica Sinica, 2005, 23(4): 683-689.

[6] Lu Huayu, Yi Shuangwen, Xu Zhiwei, et al. Chinese deserts and sand fields in Last Glacial Maximum and Holocene Optimum[J]. Chinese Science Bulletin, 2013, 58(23): 2775-2783.

[7] Zhou Yali, Lu Huayu, Zhang Jiafu, et al. Active and inactive phases of sand dune in Mu Us and Otindag Sandlands during late Quaternary suggested by OSL dating[J]. Journal of Desert Research, 2005, 25(3): 342-350.

[8] Yi Shuangwen, Lu Huayu, Zhou Yali, et al. The wet-dry variations of the Horqin Sandy field recorded by loess deposit of the late Quaternary[J]. Journal of Desert Research, 2006, 26(6): 869-874.

[9] Zhao Shuang, Xia Dunsheng, Jin Heling, et al. High resolution climate evolution record of the Horqin Sandy Land since about 5000 cal.aB.P.[J]. Quaternary Sciences, 2013, 33(2): 283-292.

[10] Liu Bing, Jin Heling, Sun Zhong. Climate change in East Horqin Sandy Land since 6.0 ka BP[J]. Journal of Desert Research, 2011, 31(6): 1398-1405.

[11] Xue Wenping, Jin Heling, Liu Bing, et al. Advances in the study of sand-dy land evolution and driving mechanism in the monsoonal margin area in China during the Holocene Epoch[J]. Journal of Desert Research, 2019, 39(3): 163-171.

[12] Dong Guanrong, Jin Jiong, Gao Shangyu, et al. Climatic changes since the Late Pleistocene in deserts of Northern China[J]. Quaternary Sciences, 1990, 10(3): 213-222.

[13] Xu Z W, Mason J A, Xu C, et al. Critical transitions in Chinese dunes during the past 12000 years[J]. Science Advances, 2020, 6(9): eaay8020.

[14] Zhong H E, Jie Z, Linhai Y, et al. Holocene dune mobility and forcing mechanisms at the Northern margin of the East Asian Monsoon[J]. Acta Geologica Sinica English Edition, 2013, 87(4): 1168-1178.

[15] Zhou Yali, Lu Huayu, Mason J A, et al. Photoluminescence chronosequence and Holocene climate change in the north Hunsandak Sandy Area[J]. Science China (Series D: Earth Sciences), 2008, 38(4): 452-462.

[16] Zhao H, Lu Y, Yin J. Optical dating of Holocene sand dune activities in the Horqin sand fields in Inner Mongolia, China, using the SAR protocol[J]. Quaternary Geochronology, 2007, 2(1-4): 29-33.

[17] Han Peng, Sun Jimin. Photoluminescence photometric dating study of the Hunsandak sands[J]. Quaternary Sciences, 2004, 24(4): 480.

[18] Murray A S, Wintle A G. Luminescence dating of quartz using an improved single aliquot regenerative dose protocol[J]. Radiation Measurements, 2000, 32(1): 57-73.

[19] Wintle A G, Murray A S. A review of quartz optically stimulated luminescence characteristics and their relevance in single aliquot regeneration dating protocols[J]. Radiation Measurements, 2006, 41(4): 369-391.

[20] Prescott J R, Hutton J T. Cosmic ray contributions to dose rates for luminescence and ESR dating: Large depths and long term time variations[J]. Radiation Measurements, 1994, 23(2): 497-500.

[21] Lu H Y, Mason J A, Stevens T, et al. Response of surface processes to climatic change in the dune fields and Loess Plateau of North China during the late Quaternary[J]. Earth Surface Processes and Landforms, 2011, 36(12): 1590-1605.

[22] Ding Z L, Derbyshire E, Yang S L, et al. Stepwise expansion of desert environment across northern China in the past 3.5 Ma and implications for monsoon evolution[J]. Earth and Planetary Science Letters, 2005, 237(1-2): 45-55.

[23] Laskar J, Robutel P, Joutel F, et al. A long term numerical solution for the insolation quantities of the Earth[J]. Astronomy & Astrophysics, 2004, 428(1): 261-285.

[24] Chen F H, Xu Q H, Chen J H, et al. East Asian summer monsoon precipitation variability since the last deglaciation[J]. Scientific Reports, 2015, 5(1): 1-11.

[25] Yang Xiaoping, Liang Peng, Fang Yiman, et al. Chinese Deserts and Environmental Changes[M]. Beijing: Science Press, 2024.

[26] Yang Ping. Paleoclimate Changes of Deserts of Eastern China Recorded by Sandy Paleosol[D]. Jinhua: Zhejiang Normal University, 2014.

[27] Tian Yaqi, Zhou Yali, Sun Xiaowei, et al. Optically stimulated luminescence chronology and climate change in the Otindag Sandy and since the Last Glacial Maximum[J/OL]. Acta Sedimentologica Sinica, 1-20 [2024-07-15].

[28] Yang Xiaogang, Baoyin, Zhang Jing, et al. Strengthening grassland ecological protection and restoration in Keshiketeng Banner to promote the sustainable development of grassland resources[J]. Inner Mongolia Forestry, 2022(7): 9-11.

[29] Yang X, Wang X, Liu Z, et al. Initiation and variation of the dune fields in semi-arid China with a special reference to the Hunshandake Sandy Land, Inner Mongolia[J]. Quaternary Science Reviews, 2013, 78: 369-380.

[30] Yang Lirong, Yue Leping. The environmental transformation from late last glacial to Holocene of Otindag Sandy Land[J]. Journal of Earth Environment, 2011, 2(1): 301-306.

[31] Zheng Lin, Xie Dong, Yu Yao, et al. Analysis of climate change in Otindag Sandy Land from 1961 to 2018[J]. Modern Agricultural Science and Technology, 2024(19): 117-120.

[32] Yao Shuzhen, Wang Busheng, Du Yinghong, et al. Analysis of precipitation resources in the Kashketeng Banner[J]. Journal of Northern Agriculture, 2012(3): 108-109.

[33] Zhou Yali, Lu Huayu, Zhang Xiaoyan, et al. Changes of the before of Otindag Sand field (northern China) during the last glacial maximum and Holocene optimum[J]. Quaternary Sciences, 2013, 33(2): 228-242.

[34] Xu Zhiwei, Lu Huayu. Aeolian environmental change studies in the Mu Us Sandy Land, north central China: Theory and recent progress[J]. Acta Geographica Sinica, 2021, 76(9): 2203-2223.

[35] Yang Xiaoping, Liang Peng, Zhang Deguo, et al. Holocene aeolian stratigraphic sequences in the eastern portion of the desert belt (sand seas and sandy lands) in northern China and their palaeoenvironmental implications[J]. Science China Earth Sciences, 2019, 49(8): 1293-1307.