青海湖流域草甸土光释光年代学研究
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摘要
高山草甸土是青藏高原的主要土壤类型,其特征为土层薄、土壤发育微弱,但由于土壤具体的发育时代尚不明晰,限制了对草甸土成土过程和气候背景的理解。选取青海湖流域西南部的橡皮山顶草甸土两个剖面(XPSD1、XPSD2)和东南部的日月山垭口两个剖面(RYS1、RYS2)进行了光释光(Optically Stimulated Luminescence, OSL)年代学研究,系统分析草甸土中颗粒(38～63μm)石英单片再生法测年的可靠性,探讨了草甸土发育的气候背景。结果表明:(1)OSL测年方法可有效运用于高山草甸土的测年中,释光自检验表明该测年结果可靠。(2)四个剖面的年代结果显示,现存的草甸土主要是晚全新世(4～0 ka)形成的,可能是相对干冷气候下的产物,其成土发育过程以风尘加积为主。(3)橡皮山顶2号剖面底部的黄土母质年代为16.2±1.8 ka,与上部土壤呈假整合接触,存在约14 ka的沉积间断。
【Objective】Soil chronology is of great pedogenetic significance, for it is closely related to the forming and developing processes of a soil. In this paper, the Optically Stimulated Luminescence(OSL) dating method was employed to determine age of the alpine meadow soil in the Qinghai Lake basin on the northeast fringe of the Qingzang Plateau. Four alpine meadow soil profiles(XPSD1, XPSD2, RYS1 and RYS2) were prepared for dating. Adaptability and reliability of the OSL dating method for alpine meadow soils in the Qinghai Lake basin was evaluated. Pedogenic process and its climatic background were also discussed. 【Method】The silt-sized(38～63 μm) quartz OSL single-aliquot regenerative(SAR) dose protocol was used to acquire equivalent dose(De). OSL signals of all the samples decayed very quickly, displaying characteristics of the signals of the typical fast quartz fraction. The preheating test set 240 ℃ as preheating temperature. All De distributed quite concentratively, showing a Gaussian distribution curve, which demonstrates that the quartz particles in the profile of Xiangpishan were well bleached before deposition. Environmental dose rates were determined using the inductively coupled plasma mass spectrometry(ICP-MS). Eventually age of the meadow soil of the profile was determined. In addition, development of the soil was characterized through analysis of particle size and organic matter content of the soil.【Result】According to the theory of pedogenesis, the genetic horizon of the meadow soil could be divided into grass felty layer(Afe), humus layer(Ah), parent material layer overlapped with a humus layer(CAhb) and parent rock layer(C). The bottom of XPSD1, XPSD2, RYS1 and RYS2 dated back 0.9±0.1 ka, 16.2±1.8 ka, 3.2±0.2 ka and 3.7±0.2 ka, respectively. The parent materials of the alpine meadow soil in the Qinghai Lake basin was mainly of aeolian loess deposit, with 50%～75% of silt, 10%～40% of sand and 10%～20% of clay, so the soil is sorted as sandy silt. The aeolian dust plays an important role in the pedogenetic process of the alpine meadow soil in the Qinghai Lake basin. Considering the alpine meadow soil features strong grass and humus accumulation, the OSL of the bottom of the Ah layer or the interface between the Ah and CAhb layers is used as indicator for dating of the alpine meadow soil. The OSL dating results demonstrate that the meadow soil in the Qinghai Lake basin developed mainly during late Holocene(4～0 ka). The phenomenon of an inverted chronosequence of old upper layer(2.6±0.1 ka) and new bottom layer(70 cm depth, 0.6±0.1 ka) was discovered at Profile XPSD2, which could probably be attributed to the effect of freezing and thawing erosion.【Conclusion】The OSL dating method is validated to be adaptable and reliable for dating alpine meadow soils. The alpine meadow soil in the Qinghai Lake basin is derived from aeolian deposits, and follows the mode of aeolian dust aggradation in soil development. The alpine meadow soil in the Qinghai Lake basin formed mainly during the late Holocene(4～0 ka) and is might be a product of dry and cold climate, taking into account the environmental records of the region. In profile XPSD2, the bottom loess parent material layer goes in parallel unconformable contact with the upper soil layer, showing a deposition hiatus of～14 ka.
【Objective】Soil chronology is of great pedogenetic significance, for it is closely related to the forming and developing processes of a soil. In this paper, the Optically Stimulated Luminescence(OSL) dating method was employed to determine age of the alpine meadow soil in the Qinghai Lake basin on the northeast fringe of the Qingzang Plateau. Four alpine meadow soil profiles(XPSD1, XPSD2, RYS1 and RYS2) were prepared for dating. Adaptability and reliability of the OSL dating method for alpine meadow soils in the Qinghai Lake basin was evaluated. Pedogenic process and its climatic background were also discussed. 【Method】The silt-sized(38～63 μm) quartz OSL single-aliquot regenerative(SAR) dose protocol was used to acquire equivalent dose(De). OSL signals of all the samples decayed very quickly, displaying characteristics of the signals of the typical fast quartz fraction. The preheating test set 240 ℃ as preheating temperature. All De distributed quite concentratively, showing a Gaussian distribution curve, which demonstrates that the quartz particles in the profile of Xiangpishan were well bleached before deposition. Environmental dose rates were determined using the inductively coupled plasma mass spectrometry(ICP-MS). Eventually age of the meadow soil of the profile was determined. In addition, development of the soil was characterized through analysis of particle size and organic matter content of the soil.【Result】According to the theory of pedogenesis, the genetic horizon of the meadow soil could be divided into grass felty layer(Afe), humus layer(Ah), parent material layer overlapped with a humus layer(CAhb) and parent rock layer(C). The bottom of XPSD1, XPSD2, RYS1 and RYS2 dated back 0.9±0.1 ka, 16.2±1.8 ka, 3.2±0.2 ka and 3.7±0.2 ka, respectively. The parent materials of the alpine meadow soil in the Qinghai Lake basin was mainly of aeolian loess deposit, with 50%～75% of silt, 10%～40% of sand and 10%～20% of clay, so the soil is sorted as sandy silt. The aeolian dust plays an important role in the pedogenetic process of the alpine meadow soil in the Qinghai Lake basin. Considering the alpine meadow soil features strong grass and humus accumulation, the OSL of the bottom of the Ah layer or the interface between the Ah and CAhb layers is used as indicator for dating of the alpine meadow soil. The OSL dating results demonstrate that the meadow soil in the Qinghai Lake basin developed mainly during late Holocene(4～0 ka). The phenomenon of an inverted chronosequence of old upper layer(2.6±0.1 ka) and new bottom layer(70 cm depth, 0.6±0.1 ka) was discovered at Profile XPSD2, which could probably be attributed to the effect of freezing and thawing erosion.【Conclusion】The OSL dating method is validated to be adaptable and reliable for dating alpine meadow soils. The alpine meadow soil in the Qinghai Lake basin is derived from aeolian deposits, and follows the mode of aeolian dust aggradation in soil development. The alpine meadow soil in the Qinghai Lake basin formed mainly during the late Holocene(4～0 ka) and is might be a product of dry and cold climate, taking into account the environmental records of the region. In profile XPSD2, the bottom loess parent material layer goes in parallel unconformable contact with the upper soil layer, showing a deposition hiatus of～14 ka.
引文
[1]陈怀满.环境土壤学.北京:科学出版社,2010Chen H M.Environmental soil science(In Chinese).Beijing:Science Press,2010
[2]Jenny H.The soil resource:Origin and behavior.New York:Springer-Verlag,1984:102
[3]Cao G M,Tang Y H,Mo W H,et al.Grazing intensity alters soil respiration in an alpine meadow on the Tibetan Plateau.Soil Biology&Biochemistry,2004,36(2):237-243
[4]赵新全.高寒草甸生态系统与全球变化.北京:科学出版社,2009:1-40Zhao X Q.Ecological of alpine meadow ecosystem and the global change(In Chinese).Beijing:Science Press,2009:1-40
[5]Kaiser K,Schoch W H,Miehe G.Holocene paleosols and colluvial sediments in Northeast Tibet(Qinghai Province,China):Properties,dating and paleoenvironmental implications.Catena,2007,69(2):91-102
[6]严振英,李浩.试论高山草甸土及其与草畜的关系.甘肃农业科技,1994,(12):29-30Yan Z Y,Li H.The research of alpine meadow soil and its relation with grass-livestock(In Chinese).Agricultural Science and Technology of Gansu,1994,(12):29-30
[7]林永崇,冯金良,张继峰,等.藏北高原安多地区高山草甸土的母质成因及其成土模式.山地学报,2012,30(6):709-720Lin Y C,Feng J L,Zhang J F,et al.Origin of parent materials and pedogensis of alpine meadow soils in Amdo,Northern Tibetan Plateau(In Chinese).Journal of Mountain science,2012,30(6):709-720
[8]Lu H Y,Zhao C F,Joseph M,et al.Holocene climatic changes revealed by aeolian deposits from the Qinghai Lake area(northeastern Qinghai-Tibetan Plateau)and possible forcing mechanisms.Holocene,2011,21(2):297-304
[9]Liu X J,Lai Z P,Yu L P,et al.Luminescence chronology of aeolian deposits from the Qinghai Lake area in the Northeastern Qinghai-Tibetan Plateau and its palaeoenvironmental implications.Quaternary Geochronology,2012,10:37-43
[10]Lu R J,Jia F F,Gao S Y,et al.Holocene aeolian activity and climatic change in Qinghai Lake basin,northeastern Qinghai-Tibetan Plateau.Palaeogeography,Palaeoclimatology,Palaeoecology,2015,430:1-10
[11]E C Y,Lai Z P,Hou G L,et al.Age determination for a Neolithic site in northeastern Qinghai-Tibetan Plateau using a combined luminescence and radiocarbon dating.Quaternary Geochronology,2015,30:411-415
[12]鹿化煜,马海州,谭红兵,等.西宁黄土堆积记录的最近13万年高原季风气候变化.第四纪研究,2001,21(5):416-426Lu H Y,Ma H Z,Tan H B,et al.Plateau Monsoon variations during the past 0.13 Ma indicated by loess deposit at Xining,Northeast Qinghai,China(In Chinese).Quaternary Sciences,2001,21(5):416-426
[13]Liu X J,Xiao G Q,E C Y,et al.Accumulation and erosion of aeolian sediments in the northeastern Qinghai-Tibetan Plateau and implications for provenance to the Chinese Loess Plateau.Journal of Asian Earth Sciences,2017,135:166-174
[14]Liu X J,Lai Z P,Fan Q S,et al.Timing for high lake levels of Qinghai Lake in the Qinghai-Tibetan Plateau since the Last Interglaciation based on quartz OSL dating.Quaternary Geochronology,2010,5(2/3):218-222
[15]Sun Y J,E C Y,Lai Z P,et al.Luminescence dating of prehistoric hearths in Northeast Qinghai Lake and its paleoclimatic implication.Archaeological&Anthropological Sciences,2017,DOI:10.1007/s12520-017-0472-y
[16]常秋芳,芦宝良,赖忠平,等.青海南山风成沉积光释光年代学研究.盐湖研究,2016,24(2):54-61Chang Q F,Lu B L,Lai Z P,et al.The optically stimulated luminescence study of aeolian deposits in Qinghai South Mountain(In Chinese).Journal of Salt Lake Research,2016,24(2):54-61
[17]马玉伟.青海湖地区黄土光释光测年及其环境意义.北京:中国科学院研究生院,2011Ma Y W.Optically Stimulated Luminescence chronology for the loess in the Qinghai Lake and its palaeoenvironmental implications(In Chinese).Beijing:Graduate School of the Chinese Academy of Sciences,2011
[18]赵存法,鹿化煜,周亚利,等.青海湖地区冰消期以来气候变化的黄土记录.高校地质学报,2009,15(1):135-140Zhao C F,Lu H Y,Zhou Y L,et al.Palaeoclimate changes recorded by loess deposit around Qinghai Lake(Northeastern Qinghai-Tibetan Plateau)since last deglaciation(In Chinese).Geological Journal of China Universities,2009,15(1):135-140
[19]青海省地方志编纂委员会.青海省志:青海湖志.西宁:青海人民出版社,1998:41-44Editorial Board of Local Chronicles of Qinghai Provi n c e.Q i n g h a i P r o v i n c e L o c a l C h r o n i c l e s-Q i n g h a i L a k e r e c o r d s(I n C h i n e s e).x i n i n g:Q i n g h a i People‘s Publishing House,1998:41-44
[20]左克成,乐炎舟.青海高山草甸土的形成及其肥力评价.土壤学报,1980,17(4):308-318Zuo K C,Le Y Z.Formation and fertility of the alpine meadow soil in Qinghai Province(In Chinese).Acta Pedologica Sinica,1980,17(4):308-318
[21]鹿化煜,安芷生.前处理方法对黄土沉积物粒度测量影响的实验研究.科学通报,1997,42(23):2535-2538Lu H Y,An Z S.Experimental study of pretreatment methods on the measurement of grain size distribution of loess sediment(In Chinese).Chinese Science Bulletin,1997,42(23):2535-2538
[22]Murray A S,Wintle A G.Luminescence dating of quartz using an improved single-aliquot regenerative-dose protocol.Radiation Measurements,2000,32(1):57-73
[23]Guérin G,Mercier N,Nathan R,et al.On the use of the infinite matrix assumption and associated concepts:A critical review.Radiation Measurements,2012,47(9):778-785
[24]Lai Z P,Z?ller L,Fuchs M,et al.Alpha efficiency determination for OSL of quartz extracted from Chinese loess.Radiation Measurements,2008,43(2/6):767-770
[25]Prescott J R,Hutton J T.Cosmic ray contributions to dose rates for luminescence and ESR dating:Large depths and long-term time variations.Radiation Measurements,1994,23(2/3):497-500
[26]鄂崇毅,曹广超,候光良,等.青海湖江西沟黄土记录的环境演变.海洋地质与第四纪地质,2013,33(4):193-200E C Y,Cao G C,Hou G L,et al.The environmental change recorded in Jiangxigou Loess sections in Qinghai Lake region(In Chinese).Marine Geology&Quaternary Geology,2013,33(4):193-200
[27]Stauch G.Multi-decadal periods of enhanced aeolian activity on the north-eastern Tibet Plateau during the last 2ka.Quaternary Science Reviews,2016,149:91-101
[28]Stauch G.Geomorphological and palaeoclimate dynamics recorded by the formation of aeolian archives on the Tibetan Plateau.Earth-Science Reviews,2015,150:393-408
[29]Chen F H,Wu D,Chen J H,et al.Holocene moisture and East Asian summer monsoon evolution in the northeastern Tibetan Plateau recorded by Lake Qinghai and its environs:Areview of conflicting proxies.Quaternary Science Reviews,2016,154:111-129
[30]张彭熹,张保珍,钱桂敏,等.青海湖全新世以来古环境参数的研究.第四纪研究,1994,14(3):225-238Zhang P X,Zhang B Z,Qian G M,et al.The study of paleoclimatic parameter of Qinghai Lake since Holocene(In Chinese).Quaternary Sciences,1994,14(3):225-238
[31]董瑞琨,许兆义,杨成永.青藏高原的冻融侵蚀问题.人民长江,2000,31(9):39-41Dong R K,Xu Z Y,Yang C Y.Freeze-thaw erosion problems on the Qinghai-Tibet Plateau(In Chinese).Yangtze River,2000,31(9):39-41
[32]范昊明,李贵圆,周丽丽,等.冻融作用对草甸土物理力学性质的影响.沈阳农业大学学报,2011,42(1):114-117Fan H M,Li G Y,Zhou L L,et al.Effect of Freeze-Thaw on Physical and Mechanical Properties of Meadow Soil(In Chinese).Journal of Shenyang Agricultural University,2011,42(1):114-117
[33]青海省农业资源区划办公室编.青海土壤.北京:中国农业出版社,1997:68-69Office of Agricultural Resources and Regional Planning in Qinghai Province.The soil of Qinghai(In Chinese).Beijing:China Agriculture Press,1997:68-69
[2]Jenny H.The soil resource:Origin and behavior.New York:Springer-Verlag,1984:102
[3]Cao G M,Tang Y H,Mo W H,et al.Grazing intensity alters soil respiration in an alpine meadow on the Tibetan Plateau.Soil Biology&Biochemistry,2004,36(2):237-243
[4]赵新全.高寒草甸生态系统与全球变化.北京:科学出版社,2009:1-40Zhao X Q.Ecological of alpine meadow ecosystem and the global change(In Chinese).Beijing:Science Press,2009:1-40
[5]Kaiser K,Schoch W H,Miehe G.Holocene paleosols and colluvial sediments in Northeast Tibet(Qinghai Province,China):Properties,dating and paleoenvironmental implications.Catena,2007,69(2):91-102
[6]严振英,李浩.试论高山草甸土及其与草畜的关系.甘肃农业科技,1994,(12):29-30Yan Z Y,Li H.The research of alpine meadow soil and its relation with grass-livestock(In Chinese).Agricultural Science and Technology of Gansu,1994,(12):29-30
[7]林永崇,冯金良,张继峰,等.藏北高原安多地区高山草甸土的母质成因及其成土模式.山地学报,2012,30(6):709-720Lin Y C,Feng J L,Zhang J F,et al.Origin of parent materials and pedogensis of alpine meadow soils in Amdo,Northern Tibetan Plateau(In Chinese).Journal of Mountain science,2012,30(6):709-720
[8]Lu H Y,Zhao C F,Joseph M,et al.Holocene climatic changes revealed by aeolian deposits from the Qinghai Lake area(northeastern Qinghai-Tibetan Plateau)and possible forcing mechanisms.Holocene,2011,21(2):297-304
[9]Liu X J,Lai Z P,Yu L P,et al.Luminescence chronology of aeolian deposits from the Qinghai Lake area in the Northeastern Qinghai-Tibetan Plateau and its palaeoenvironmental implications.Quaternary Geochronology,2012,10:37-43
[10]Lu R J,Jia F F,Gao S Y,et al.Holocene aeolian activity and climatic change in Qinghai Lake basin,northeastern Qinghai-Tibetan Plateau.Palaeogeography,Palaeoclimatology,Palaeoecology,2015,430:1-10
[11]E C Y,Lai Z P,Hou G L,et al.Age determination for a Neolithic site in northeastern Qinghai-Tibetan Plateau using a combined luminescence and radiocarbon dating.Quaternary Geochronology,2015,30:411-415
[12]鹿化煜,马海州,谭红兵,等.西宁黄土堆积记录的最近13万年高原季风气候变化.第四纪研究,2001,21(5):416-426Lu H Y,Ma H Z,Tan H B,et al.Plateau Monsoon variations during the past 0.13 Ma indicated by loess deposit at Xining,Northeast Qinghai,China(In Chinese).Quaternary Sciences,2001,21(5):416-426
[13]Liu X J,Xiao G Q,E C Y,et al.Accumulation and erosion of aeolian sediments in the northeastern Qinghai-Tibetan Plateau and implications for provenance to the Chinese Loess Plateau.Journal of Asian Earth Sciences,2017,135:166-174
[14]Liu X J,Lai Z P,Fan Q S,et al.Timing for high lake levels of Qinghai Lake in the Qinghai-Tibetan Plateau since the Last Interglaciation based on quartz OSL dating.Quaternary Geochronology,2010,5(2/3):218-222
[15]Sun Y J,E C Y,Lai Z P,et al.Luminescence dating of prehistoric hearths in Northeast Qinghai Lake and its paleoclimatic implication.Archaeological&Anthropological Sciences,2017,DOI:10.1007/s12520-017-0472-y
[16]常秋芳,芦宝良,赖忠平,等.青海南山风成沉积光释光年代学研究.盐湖研究,2016,24(2):54-61Chang Q F,Lu B L,Lai Z P,et al.The optically stimulated luminescence study of aeolian deposits in Qinghai South Mountain(In Chinese).Journal of Salt Lake Research,2016,24(2):54-61
[17]马玉伟.青海湖地区黄土光释光测年及其环境意义.北京:中国科学院研究生院,2011Ma Y W.Optically Stimulated Luminescence chronology for the loess in the Qinghai Lake and its palaeoenvironmental implications(In Chinese).Beijing:Graduate School of the Chinese Academy of Sciences,2011
[18]赵存法,鹿化煜,周亚利,等.青海湖地区冰消期以来气候变化的黄土记录.高校地质学报,2009,15(1):135-140Zhao C F,Lu H Y,Zhou Y L,et al.Palaeoclimate changes recorded by loess deposit around Qinghai Lake(Northeastern Qinghai-Tibetan Plateau)since last deglaciation(In Chinese).Geological Journal of China Universities,2009,15(1):135-140
[19]青海省地方志编纂委员会.青海省志:青海湖志.西宁:青海人民出版社,1998:41-44Editorial Board of Local Chronicles of Qinghai Provi n c e.Q i n g h a i P r o v i n c e L o c a l C h r o n i c l e s-Q i n g h a i L a k e r e c o r d s(I n C h i n e s e).x i n i n g:Q i n g h a i People‘s Publishing House,1998:41-44
[20]左克成,乐炎舟.青海高山草甸土的形成及其肥力评价.土壤学报,1980,17(4):308-318Zuo K C,Le Y Z.Formation and fertility of the alpine meadow soil in Qinghai Province(In Chinese).Acta Pedologica Sinica,1980,17(4):308-318
[21]鹿化煜,安芷生.前处理方法对黄土沉积物粒度测量影响的实验研究.科学通报,1997,42(23):2535-2538Lu H Y,An Z S.Experimental study of pretreatment methods on the measurement of grain size distribution of loess sediment(In Chinese).Chinese Science Bulletin,1997,42(23):2535-2538
[22]Murray A S,Wintle A G.Luminescence dating of quartz using an improved single-aliquot regenerative-dose protocol.Radiation Measurements,2000,32(1):57-73
[23]Guérin G,Mercier N,Nathan R,et al.On the use of the infinite matrix assumption and associated concepts:A critical review.Radiation Measurements,2012,47(9):778-785
[24]Lai Z P,Z?ller L,Fuchs M,et al.Alpha efficiency determination for OSL of quartz extracted from Chinese loess.Radiation Measurements,2008,43(2/6):767-770
[25]Prescott J R,Hutton J T.Cosmic ray contributions to dose rates for luminescence and ESR dating:Large depths and long-term time variations.Radiation Measurements,1994,23(2/3):497-500
[26]鄂崇毅,曹广超,候光良,等.青海湖江西沟黄土记录的环境演变.海洋地质与第四纪地质,2013,33(4):193-200E C Y,Cao G C,Hou G L,et al.The environmental change recorded in Jiangxigou Loess sections in Qinghai Lake region(In Chinese).Marine Geology&Quaternary Geology,2013,33(4):193-200
[27]Stauch G.Multi-decadal periods of enhanced aeolian activity on the north-eastern Tibet Plateau during the last 2ka.Quaternary Science Reviews,2016,149:91-101
[28]Stauch G.Geomorphological and palaeoclimate dynamics recorded by the formation of aeolian archives on the Tibetan Plateau.Earth-Science Reviews,2015,150:393-408
[29]Chen F H,Wu D,Chen J H,et al.Holocene moisture and East Asian summer monsoon evolution in the northeastern Tibetan Plateau recorded by Lake Qinghai and its environs:Areview of conflicting proxies.Quaternary Science Reviews,2016,154:111-129
[30]张彭熹,张保珍,钱桂敏,等.青海湖全新世以来古环境参数的研究.第四纪研究,1994,14(3):225-238Zhang P X,Zhang B Z,Qian G M,et al.The study of paleoclimatic parameter of Qinghai Lake since Holocene(In Chinese).Quaternary Sciences,1994,14(3):225-238
[31]董瑞琨,许兆义,杨成永.青藏高原的冻融侵蚀问题.人民长江,2000,31(9):39-41Dong R K,Xu Z Y,Yang C Y.Freeze-thaw erosion problems on the Qinghai-Tibet Plateau(In Chinese).Yangtze River,2000,31(9):39-41
[32]范昊明,李贵圆,周丽丽,等.冻融作用对草甸土物理力学性质的影响.沈阳农业大学学报,2011,42(1):114-117Fan H M,Li G Y,Zhou L L,et al.Effect of Freeze-Thaw on Physical and Mechanical Properties of Meadow Soil(In Chinese).Journal of Shenyang Agricultural University,2011,42(1):114-117
[33]青海省农业资源区划办公室编.青海土壤.北京:中国农业出版社,1997:68-69Office of Agricultural Resources and Regional Planning in Qinghai Province.The soil of Qinghai(In Chinese).Beijing:China Agriculture Press,1997:68-69