邙山黄土古土壤S_2沉积以来的微量和稀土元素地球化学特征及其物源指示意义
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摘要
地处黄河三门峡段下游冲积平原附近的邙山黄土,中更新世晚期以来沉积厚度近100 m,远大于洛川、渭南等典型黄土剖面的同期堆积。前人从沉积速率、粒度等方面进行研究,推测邙山黄土堆积可能源于三门峡段下游的冲积物,但尚无微量和稀土元素地球化学方面的证据。对黄土中古土壤S_2沉积以来的邙山黄土及三门峡地区黄土进行了微量元素和稀土元素测试,并与黄土高原、淮南等地区典型黄土的元素地球化学特征进行了对比。结果表明,与黄土高原等典型黄土相比,邙山黄土明显富Zr、Hf贫Th、Cs,在Zr/Hf、Nb/Th、Y/Th、La/Th等元素比值上差异显著;La-Th-Sc和Th-Sc-Zr/10三角图解也显示,邙山黄土与黄土高原等典型黄土的投影区域明显不同。在稀土元素特征上,邙山黄土在ΣREE及表征REE内部分馏程度的LREE/HREE、La/Eu上与黄土高原等典型黄土存在明显不同,10*Hf-Ce-Yb和La-Zr/10-Ce三角图解中的投影区域也与其他典型黄土有显著区别。微量元素及稀土元素地球化学特征显示,邙山黄土与黄土高原等典型黄土的物源可能并不完全一致,邙山黄土可能相当一部分源于近源冲积物。邙山附近广阔的黄河冲积平原可能是S2以来邙山黄土巨厚堆积的重要物源区。
The Mangshan(MS) loess is located on the south bank of the Yellow River near the southwestern part of the North China Plain,well outside of the Chinese Loess Plateau(CLP). Stratigraphically,the uppermost ~ 100 m loess-paleosol sequence,formed in the last two climate cycles,is extremely thick compared with the eolian deposits in the CLP. Previous researches revealed that,unlike other sections in the CLP,the MS loess since deposit of S_2(about 200 ka) is characterized by exceptionally high accumulation rates,lower magnetic susceptibility values and coarser grain-size distribution. The Yellow River flood plain adjacent to the MS loess is considered as the dominant source of the accumulated loess,but the proof in geochemistry is absent. The trace element(TE) and rare earth element(REE) characteristics of the MS loess bear information about climate change,and may give insight into the dust sources. We present the loess comparison of TE and REE compositions in MS,Sanmenxia(SMX,i. e.,the Sanmen Gorge) area,CLP and Huainan(HN) since deposit of S_2. The results show substantial differences in Zr/Hf,Nb/Th,Y/Th and La/Th values when compared the MS loess with the SMX,CLP and HN loess,leading to an important indicator for provenance. Specifically,the MS loess shows a higher Zr,Hf and a lower Th,Cs,implying a coarser grain-size distribution. The difference in TE composition between the MS loess and the other eolian deposits is also shown in the ternary diagrams of La-Th-Sc and Zr/10-Th-Sc,in which the MS loess projection region is incompletely consistent with that of the SMX,CLP and HN loess. Most probably,these were all derived from the difference of dust sources. The REE study of the MS loess and its comparison with the loess of SMX,CLP and HN show a lower ΣREE,LREE/HREE and La/Eu value. The MS loess samples exhibit an exceptionally distinctive projection region in the ternary diagrams of 10* Hf-Ce-Yb and La-Zr/10-Ce. Both of them are reasonably classified as another provenance. All results present that the dust source of the MS loess may be disparate from that of SMX,CLP and HN,implying that the alluvial fan adjacent to MS may contribute significantly to the accumulation of the MS loess-palaeosol sequences since deposit of S_2. The Yellow River flowed out through the Sanmenxia in about 200 ka,releasing most of its suspended load due to a dramatic decrease in gradient and forming an excessive deposition of the alluvial fan. Such excessive deposit compensation provided a major source for the MS loess accumulation.
The Mangshan(MS) loess is located on the south bank of the Yellow River near the southwestern part of the North China Plain,well outside of the Chinese Loess Plateau(CLP). Stratigraphically,the uppermost ~ 100 m loess-paleosol sequence,formed in the last two climate cycles,is extremely thick compared with the eolian deposits in the CLP. Previous researches revealed that,unlike other sections in the CLP,the MS loess since deposit of S_2(about 200 ka) is characterized by exceptionally high accumulation rates,lower magnetic susceptibility values and coarser grain-size distribution. The Yellow River flood plain adjacent to the MS loess is considered as the dominant source of the accumulated loess,but the proof in geochemistry is absent. The trace element(TE) and rare earth element(REE) characteristics of the MS loess bear information about climate change,and may give insight into the dust sources. We present the loess comparison of TE and REE compositions in MS,Sanmenxia(SMX,i. e.,the Sanmen Gorge) area,CLP and Huainan(HN) since deposit of S_2. The results show substantial differences in Zr/Hf,Nb/Th,Y/Th and La/Th values when compared the MS loess with the SMX,CLP and HN loess,leading to an important indicator for provenance. Specifically,the MS loess shows a higher Zr,Hf and a lower Th,Cs,implying a coarser grain-size distribution. The difference in TE composition between the MS loess and the other eolian deposits is also shown in the ternary diagrams of La-Th-Sc and Zr/10-Th-Sc,in which the MS loess projection region is incompletely consistent with that of the SMX,CLP and HN loess. Most probably,these were all derived from the difference of dust sources. The REE study of the MS loess and its comparison with the loess of SMX,CLP and HN show a lower ΣREE,LREE/HREE and La/Eu value. The MS loess samples exhibit an exceptionally distinctive projection region in the ternary diagrams of 10* Hf-Ce-Yb and La-Zr/10-Ce. Both of them are reasonably classified as another provenance. All results present that the dust source of the MS loess may be disparate from that of SMX,CLP and HN,implying that the alluvial fan adjacent to MS may contribute significantly to the accumulation of the MS loess-palaeosol sequences since deposit of S_2. The Yellow River flowed out through the Sanmenxia in about 200 ka,releasing most of its suspended load due to a dramatic decrease in gradient and forming an excessive deposition of the alluvial fan. Such excessive deposit compensation provided a major source for the MS loess accumulation.
引文
[1]刘东生.黄土与环境[M].北京:科学出版社,1985:1-302.LIU T S.Loess and Environment[M].Beijing:Science Press,1985:1-302.
[2]DING Z L,SUN J M,YANG S L,et al.Geochemistry of the Pliocene red clay formation in the Chinese Loess Plateau and implications for its origin,source provenance and paleoclimate change[J].Geochimica et Cosmochimica Acta,2001,65(6):901-913.
[3]ZHANG L,QIN X G,LIU J Q,et al.Geochemistry of sediments from the Huaibei Plain(east China):Implications for provenance,weathering,and invasion of the Yellow River into the Huaihe River[J].Journal of Asian Earth Sciences,2016,121:72-83.
[4]DING Z L,LIU T S,RUTTER N W,et al.Ice-volume forcing of East Asian winter monsoon variations in the past800,000 years[J].Quaternary Research,1995,44(2):149-159.
[5]GALLET S,JAHN B M,TORII M.Geochemical characterization of the Luochuan loess-paleosol sequence,China,and paleoclimatic implications[J].Chemical Geology,1996,133(1/2/3/4):67-88.
[6]HESLOP D,LANGEREIS C G,DEKKERS M J.A new astronomical timescale for the loess deposits of Northern China[J].Earth&Planetary Science Letters,2000,184(1):125-139.
[7]KUKLA G,AN Z S.Loess stratigraphy in Central China paleogeography[J].Palaeogeography,Palaeoclimatology&Palaeoecology,1989,72(89):203-225.
[8]DING Z L,DERBYSHIRE E,YANG S L,et al.Stacked2.6-Ma grain size record from the Chinese loess based on five sections and correlation with the deep-seaδ18O record[J].Paleoceanography,2002,17(3),DOI 10.1029/2001PA000725.
[9]DING Z L,SUN J M,RUTTER W N,et al.Changes in sand content of loess deposits along a north-south transect of the Chinese Loess Plateau and the implications for desert variations[J].Quaternary Research,1999,52(1):56-62.
[10]DOUGLAS W B,LI J J.Age and paleoclimatic significance of the loess of Lanzhou,North China[J].Nature,1985,316(6027):429-431.
[11]KUKLA G.Loess stratigraphy in central China[J].Quaternary Science Reviews,1987,6(3/4):191-219.
[12]ZHENG H B,AN Z S,JOHN S.New contribution to Chinese Plio-Pleistocene magnetostratigraphy[J].Physics of the Earth and Planetary Interiors,1992,70:146-153.
[13]NATASA J V,MICHAEL J S,KENNETH L V.Duration dependence of magnetic susceptibility enhancement in the Chinese loess-palaeosols of the past 620 ky[J].Palaeogeography,Palaeoclimatology&Palaeoecology,2004,211(3/4):271-288.
[14]JIANG F C,FU J L,WANG S B,et al.Formation of the Yellow River,inferred from loess-palaeosol sequence in Mangshan and lacustrine sediments in Sanmen Gorge,China[J].Quaternary International,2007,175(1):62-70.
[15]SUN J M.Provenance of lows material land formation of loess deposits on the Chinese Loess Plateau[J].Earth and Planetary Science Letters,2002,203(3/4):845-859.
[16]杨帅斌,乔彦松,彭莎莎等.青藏高原东北缘黄土的地球化学特征及其对物源和风化强度的指示意义[J].第四纪研究,2017,37(1):1-13.YANG S B,QIAO Y S,PENG S S,et al.Geochemical characteristics of eolian and deposits in the northeastern margin of the Tibetan Plateau and implications for provenance and weathering intensity[J].Quaternary Sciences,2017,37(1):1-13.
[17]季军良,郑洪波,刘锐等.邙山黄土地层再研究[J].海洋地质与第四纪地质,2004,24(4):101-108.JI J L,ZHENG H B,LIU R,et al.Restudy on the stratigraphy of Mangshan loess[J].Marine Geology&Quaternary Geology,2004,24(4):101-108.
[18]ZHENG H B,YANG X D,JI J L,et al.Ultra-high rates of loess sedimentation at Zhengzhou since Stage 7:Implication for the Yellow River erosion of the Sanmen Gorge[J].Geomorphology,2007,85(3/4):131-142.
[19]蒋复初,傅建利,王书兵,等.关于黄河贯通三门峡的时代[J].地质力学学报,2005,11(4):293-301.JIANG F C,FU J L,WANG S B,et al.The age of the Yellow River passing thought the Sanmen Gorge[J].Journal of Geomechanics,2005,11(4):293-301.
[20]QIU F Y,ZHOU L P.A new luminescence chronology for the Mangshan loess-palaeosol sequence on the southern bank of the Yellow River in Henan,central China[J].Quaternary Geochronology,2015,30:24-33.
[21]MAARTEN A P,ZHENG H B,KAY B,et al.Dust supply from river floodplains:the case of the lower Huang He(Yellow River)recorded in a loess-palaeosol sequence from the Mangshan Plateau[J].Journal of Quaternary Science,2009,24(1):75-84.
[22]顾兆炎,韩家,刘东生.中国第四纪黄土地球化学研究进展[J].第四纪研究,2000,20(1):41-55.GU Z Y,HAN J,LIU T S.Progress in geochemical research on the loess and other Quaternary deposits in China[J].Quaternary Sciences,2000,20(1):41-55.
[23]TAYLOR S R,Mc LENNAN S M.The continental crust:its composition and evolution[M].Oxford:Blackwell Scientific Pub,1985:38-43.
[24]Mc LENNAN S M.Rare earth elements and sedimentary rocks:influence of provenance and sedimentary processes[J].Reviews in Mineralogy,1989,21(8):169-200.
[25]LIU C Q,MASUDA A,OKADA A,et al.A geochemical study of loess and desert sand in northern China:Implications for continental crust weathering and composition[J].Chemical Geology,1993,106(3/4):359-374.
[26]Mc LENNAN S M,HEMMING S,Mc DANIEL D K,et al.Geochemical approaches to sedimentation,provenance,and tectonics[J].Special Paper of the Geological Society of America,1993,284:21-40.
[27]刘英俊,曹励明.元素地球化学导论[M].北京:地质出版社,1987.LIU Y J,CAO L M.An introduction to element geochemistry[M].Beijing:Geological Publishing House,1987.
[28]BARTH M G,MCDONOUGH W F,RUDNICK R L.Tracking the budget of Nb and Ta in the continental crust[J].Chemical Geology,2000,165(3/4):197-213.
[29]TAYLOR S R,Mc LENNAN S M,Mc CULLOCH M T.Geochemistry of loess,continental crustal composition and crustal model ages[J].Geochimica et Cosmochimica Acta,1983,47(11):1897-1905.
[30]WANG X,GRIFFIN W L,CHEN J.Hf contents and Zr/Hf ratios in granitic zircons[J].Geochemical Journal,2010,44(1):65-72.
[31]NESBITT H W,MARKOVICS G,PRICE R C.Chemical processes affecting alkalis and alkaline earths during continental weathering[J].Geochimica et Cosmochimica Acta,1980,44(11):1659-1666.
[32]JULIA A K,JOHN S,STEVEN G D.Evaluating trace elements as paleoclimate indicators:Multivariate statistical analysis of late Mississippian Pennington Formation paleosols,Kentucky,USA[J].The Journal of Geology,2008,116(3):254-268.
[33]BHATIA M R,CROOK K A.Trace element characteristics of greywackes and tectonic setting discrimination of sedimentary basins[J].Contributions to Mineralogy&Petrology,1986,92(2):181-193.
[34]CULLERS R L,PODKOVYROV V N.The source and origin of terrigenous sedimentary rocks in the Mesoproterozoic UI group,southeastern Russia[J].Precambrian Research,2002,117(3/4):157-183.
[35]GALLET S,JAHN B M,LANOV V,et al.Loess geochemistry and its implications for particle origin and composition of the upper continental crust[J].Earth&Planetary Science Letters,1998,156(3/4):157-172.
[36]FERRAT M,WEISS D J,STREKOPYTOV S,et al.Improved provenance tracing of Asian dust sources using rare earth elements and selected trace elements for palaeomonsoon studies on the eastern Tibetan Plateau[J].Geochimica et Cosmochimica Acta,2011,75(21):6374-6399.
[37]WANG S M,WU X H,ZHANG Z K,et al.Sedimentary records of environmental evolution in the Sanmen lake basin and the Yellow River running through the Sanmen Gorge eastward into the sea[J].Science in China(Series D),2002,45(7):595-608.
[38]马玉凤,李双权,潘星慧.黄河冲积扇发育研究述评[J].地理学报,2015,70(1):49-62.MA Y f,LI S Q,PAN X H.A review on development of the Yellow River alluvial fan[J].Acta Geographica Sinica,2015,70(1):49-62.
[39]ZHANG Z K,WANG S M,YANG X D,et al.Evidence of a geological event and environmental change in the catchment area of the Yellow River at 0.15 Ma.Quaternary International,2004,117(1):35-40.
[2]DING Z L,SUN J M,YANG S L,et al.Geochemistry of the Pliocene red clay formation in the Chinese Loess Plateau and implications for its origin,source provenance and paleoclimate change[J].Geochimica et Cosmochimica Acta,2001,65(6):901-913.
[3]ZHANG L,QIN X G,LIU J Q,et al.Geochemistry of sediments from the Huaibei Plain(east China):Implications for provenance,weathering,and invasion of the Yellow River into the Huaihe River[J].Journal of Asian Earth Sciences,2016,121:72-83.
[4]DING Z L,LIU T S,RUTTER N W,et al.Ice-volume forcing of East Asian winter monsoon variations in the past800,000 years[J].Quaternary Research,1995,44(2):149-159.
[5]GALLET S,JAHN B M,TORII M.Geochemical characterization of the Luochuan loess-paleosol sequence,China,and paleoclimatic implications[J].Chemical Geology,1996,133(1/2/3/4):67-88.
[6]HESLOP D,LANGEREIS C G,DEKKERS M J.A new astronomical timescale for the loess deposits of Northern China[J].Earth&Planetary Science Letters,2000,184(1):125-139.
[7]KUKLA G,AN Z S.Loess stratigraphy in Central China paleogeography[J].Palaeogeography,Palaeoclimatology&Palaeoecology,1989,72(89):203-225.
[8]DING Z L,DERBYSHIRE E,YANG S L,et al.Stacked2.6-Ma grain size record from the Chinese loess based on five sections and correlation with the deep-seaδ18O record[J].Paleoceanography,2002,17(3),DOI 10.1029/2001PA000725.
[9]DING Z L,SUN J M,RUTTER W N,et al.Changes in sand content of loess deposits along a north-south transect of the Chinese Loess Plateau and the implications for desert variations[J].Quaternary Research,1999,52(1):56-62.
[10]DOUGLAS W B,LI J J.Age and paleoclimatic significance of the loess of Lanzhou,North China[J].Nature,1985,316(6027):429-431.
[11]KUKLA G.Loess stratigraphy in central China[J].Quaternary Science Reviews,1987,6(3/4):191-219.
[12]ZHENG H B,AN Z S,JOHN S.New contribution to Chinese Plio-Pleistocene magnetostratigraphy[J].Physics of the Earth and Planetary Interiors,1992,70:146-153.
[13]NATASA J V,MICHAEL J S,KENNETH L V.Duration dependence of magnetic susceptibility enhancement in the Chinese loess-palaeosols of the past 620 ky[J].Palaeogeography,Palaeoclimatology&Palaeoecology,2004,211(3/4):271-288.
[14]JIANG F C,FU J L,WANG S B,et al.Formation of the Yellow River,inferred from loess-palaeosol sequence in Mangshan and lacustrine sediments in Sanmen Gorge,China[J].Quaternary International,2007,175(1):62-70.
[15]SUN J M.Provenance of lows material land formation of loess deposits on the Chinese Loess Plateau[J].Earth and Planetary Science Letters,2002,203(3/4):845-859.
[16]杨帅斌,乔彦松,彭莎莎等.青藏高原东北缘黄土的地球化学特征及其对物源和风化强度的指示意义[J].第四纪研究,2017,37(1):1-13.YANG S B,QIAO Y S,PENG S S,et al.Geochemical characteristics of eolian and deposits in the northeastern margin of the Tibetan Plateau and implications for provenance and weathering intensity[J].Quaternary Sciences,2017,37(1):1-13.
[17]季军良,郑洪波,刘锐等.邙山黄土地层再研究[J].海洋地质与第四纪地质,2004,24(4):101-108.JI J L,ZHENG H B,LIU R,et al.Restudy on the stratigraphy of Mangshan loess[J].Marine Geology&Quaternary Geology,2004,24(4):101-108.
[18]ZHENG H B,YANG X D,JI J L,et al.Ultra-high rates of loess sedimentation at Zhengzhou since Stage 7:Implication for the Yellow River erosion of the Sanmen Gorge[J].Geomorphology,2007,85(3/4):131-142.
[19]蒋复初,傅建利,王书兵,等.关于黄河贯通三门峡的时代[J].地质力学学报,2005,11(4):293-301.JIANG F C,FU J L,WANG S B,et al.The age of the Yellow River passing thought the Sanmen Gorge[J].Journal of Geomechanics,2005,11(4):293-301.
[20]QIU F Y,ZHOU L P.A new luminescence chronology for the Mangshan loess-palaeosol sequence on the southern bank of the Yellow River in Henan,central China[J].Quaternary Geochronology,2015,30:24-33.
[21]MAARTEN A P,ZHENG H B,KAY B,et al.Dust supply from river floodplains:the case of the lower Huang He(Yellow River)recorded in a loess-palaeosol sequence from the Mangshan Plateau[J].Journal of Quaternary Science,2009,24(1):75-84.
[22]顾兆炎,韩家,刘东生.中国第四纪黄土地球化学研究进展[J].第四纪研究,2000,20(1):41-55.GU Z Y,HAN J,LIU T S.Progress in geochemical research on the loess and other Quaternary deposits in China[J].Quaternary Sciences,2000,20(1):41-55.
[23]TAYLOR S R,Mc LENNAN S M.The continental crust:its composition and evolution[M].Oxford:Blackwell Scientific Pub,1985:38-43.
[24]Mc LENNAN S M.Rare earth elements and sedimentary rocks:influence of provenance and sedimentary processes[J].Reviews in Mineralogy,1989,21(8):169-200.
[25]LIU C Q,MASUDA A,OKADA A,et al.A geochemical study of loess and desert sand in northern China:Implications for continental crust weathering and composition[J].Chemical Geology,1993,106(3/4):359-374.
[26]Mc LENNAN S M,HEMMING S,Mc DANIEL D K,et al.Geochemical approaches to sedimentation,provenance,and tectonics[J].Special Paper of the Geological Society of America,1993,284:21-40.
[27]刘英俊,曹励明.元素地球化学导论[M].北京:地质出版社,1987.LIU Y J,CAO L M.An introduction to element geochemistry[M].Beijing:Geological Publishing House,1987.
[28]BARTH M G,MCDONOUGH W F,RUDNICK R L.Tracking the budget of Nb and Ta in the continental crust[J].Chemical Geology,2000,165(3/4):197-213.
[29]TAYLOR S R,Mc LENNAN S M,Mc CULLOCH M T.Geochemistry of loess,continental crustal composition and crustal model ages[J].Geochimica et Cosmochimica Acta,1983,47(11):1897-1905.
[30]WANG X,GRIFFIN W L,CHEN J.Hf contents and Zr/Hf ratios in granitic zircons[J].Geochemical Journal,2010,44(1):65-72.
[31]NESBITT H W,MARKOVICS G,PRICE R C.Chemical processes affecting alkalis and alkaline earths during continental weathering[J].Geochimica et Cosmochimica Acta,1980,44(11):1659-1666.
[32]JULIA A K,JOHN S,STEVEN G D.Evaluating trace elements as paleoclimate indicators:Multivariate statistical analysis of late Mississippian Pennington Formation paleosols,Kentucky,USA[J].The Journal of Geology,2008,116(3):254-268.
[33]BHATIA M R,CROOK K A.Trace element characteristics of greywackes and tectonic setting discrimination of sedimentary basins[J].Contributions to Mineralogy&Petrology,1986,92(2):181-193.
[34]CULLERS R L,PODKOVYROV V N.The source and origin of terrigenous sedimentary rocks in the Mesoproterozoic UI group,southeastern Russia[J].Precambrian Research,2002,117(3/4):157-183.
[35]GALLET S,JAHN B M,LANOV V,et al.Loess geochemistry and its implications for particle origin and composition of the upper continental crust[J].Earth&Planetary Science Letters,1998,156(3/4):157-172.
[36]FERRAT M,WEISS D J,STREKOPYTOV S,et al.Improved provenance tracing of Asian dust sources using rare earth elements and selected trace elements for palaeomonsoon studies on the eastern Tibetan Plateau[J].Geochimica et Cosmochimica Acta,2011,75(21):6374-6399.
[37]WANG S M,WU X H,ZHANG Z K,et al.Sedimentary records of environmental evolution in the Sanmen lake basin and the Yellow River running through the Sanmen Gorge eastward into the sea[J].Science in China(Series D),2002,45(7):595-608.
[38]马玉凤,李双权,潘星慧.黄河冲积扇发育研究述评[J].地理学报,2015,70(1):49-62.MA Y f,LI S Q,PAN X H.A review on development of the Yellow River alluvial fan[J].Acta Geographica Sinica,2015,70(1):49-62.
[39]ZHANG Z K,WANG S M,YANG X D,et al.Evidence of a geological event and environmental change in the catchment area of the Yellow River at 0.15 Ma.Quaternary International,2004,117(1):35-40.