南海北部MD12-3432站深海氧同位素MIS6期到MIS5期陆源沉积物元素比值反映的古气候变化
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摘要
海洋沉积物中的某些主微量元素与沉积物源区有着密切的联系,它们之间的比值变化受到源区化学风化强度的影响,因此这些元素的比值变化可以反映出海洋沉积物源区古气候的变化。本文研究了南海北部陆坡MD12-3432站位深海氧同位素6期和5期(MIS6/5)沉积物的主微量元素,发现其表现出良好的气候控制变化特征,K/Ti、Mg/Ti、Al/Ti、Fe/Ti、Co/Ti、Zn/Ti和V/Ti等比值在MIS 5期时较高,而在MIS6期时较低。南海北部的碎屑物质主要来自中国华南地区,沉积物中元素比值的变化表明间冰期时(MIS5)华南地区陆壳化学风化增强,说明该时期华南陆地气候环境温暖湿润,这可能是间冰期时东亚夏季风加强的结果;而冰期时南海北部沉积物源区化学风化减弱,则与此时东亚冬季风较强,华南地区气候干燥寒冷相关。同时,与表层海水生产力相关的Ba/Ti比值在间冰期较高而冰期较低,反映出南海北部在间冰期时表层生产力较高而冰期时相对较低,这可能是由于东亚夏季风增强带来更多降雨,陆地化学风化作用加强,大量营养成分随河流进入南海,导致南海北部表层海水生产力增加。
Some of the major and trace elements in marine sediments are closely related to the source area of sediments.The change of major and trace elemental ratio is affected by chemical weathering intensity in the source area.Therefore,the ratios can reflect paleoclimate change in the source area of marine sediments.In this work,we studied the major and trace elements of the sediments between Marine Isotope Stage(MIS)6 and 5 in the core of MD12-3432 on the northern slope of the South China Sea.The elemental contents showed good climate control characteristics,with K/Ti,Mg/Ti,Al/Ti,Fe/Ti,Co/Ti,Zn/Ti and V/Ti ratios higher in MIS5 but lower in MIS6.The detrital materials in the northern South China Sea mainly came from southern China.The changes of elemental ratios in sediments showed increased chemical weathering of continental crusts in southern China during the interglacial period(MIS5),indicating warm and humid climate in the South China continent during this period,possibly a result of enhanced East Asian summer monsoon during the interglacial period.The chemical weathering of the source area in northern South China Sea weakened during the glacial period,in contrast to the strong East Asian winter monsoon and cold and dry climate in southern China.At the same time,the Ba/Ti ratio related to surface seawater productivity is higher in the interglacial and lower in the glacial periods,reflecting higher surface productivity during the interglacial period and relatively lower surface productivity during the glacial period in the northern part of the South China Sea.This may be due to increased surface productivity in the northern South China Sea,as increasing East Asian summer monsoon can bring more rainfall which may lead to enhanced chemical weathering on land and large amount of nutrients entering the South China Sea through river channels.
Some of the major and trace elements in marine sediments are closely related to the source area of sediments.The change of major and trace elemental ratio is affected by chemical weathering intensity in the source area.Therefore,the ratios can reflect paleoclimate change in the source area of marine sediments.In this work,we studied the major and trace elements of the sediments between Marine Isotope Stage(MIS)6 and 5 in the core of MD12-3432 on the northern slope of the South China Sea.The elemental contents showed good climate control characteristics,with K/Ti,Mg/Ti,Al/Ti,Fe/Ti,Co/Ti,Zn/Ti and V/Ti ratios higher in MIS5 but lower in MIS6.The detrital materials in the northern South China Sea mainly came from southern China.The changes of elemental ratios in sediments showed increased chemical weathering of continental crusts in southern China during the interglacial period(MIS5),indicating warm and humid climate in the South China continent during this period,possibly a result of enhanced East Asian summer monsoon during the interglacial period.The chemical weathering of the source area in northern South China Sea weakened during the glacial period,in contrast to the strong East Asian winter monsoon and cold and dry climate in southern China.At the same time,the Ba/Ti ratio related to surface seawater productivity is higher in the interglacial and lower in the glacial periods,reflecting higher surface productivity during the interglacial period and relatively lower surface productivity during the glacial period in the northern part of the South China Sea.This may be due to increased surface productivity in the northern South China Sea,as increasing East Asian summer monsoon can bring more rainfall which may lead to enhanced chemical weathering on land and large amount of nutrients entering the South China Sea through river channels.
引文
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[22]韦刚健,刘颖,邵磊,等.南海碎屑沉积物化学组成的气候记录[J].海洋地质与第四纪地质,2003,23(3):1-4.
[23]YANG S,LI C,CAI J,et al.Geochemical compositions of core sediments in eastern China:implication for Late Cenozoic palaeoenvironmental changes[J].Palaeogeography,Palaeoclimatology,Palaeoecology,2006,229(4):287-302.
[24]NESBITT H W,YOUNG G M.Early Proterozoic climates and plate motions inferred from major element chemistry of lutites[J].Nature,1982,299:715-717.
[25]PEURANIEMI V,PULKKINEN P.Preglacial weathering crust in Ostrobothnia,western Finland,with special reference to the Raudaskyl?occurrence[J].Chemical Geology,1993,107(3/4):313-316.
[26]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.
[27]TAMBURINI F,ADATTE T,FOLLMI K B,et al.Investigating the history of East Asian monsoon and climate during the last glacialinterglacial period(0 140000years):mineralogy and geochemistry of ODP Sites 1143and 1144,South China Sea[J].Marine Geology,2003,201(1/2/3):147-168.
[28]DING Y.Monsoons over China[J].Advances in Atmospheric Sciences,1994,11(2):252-252.
[29]PAYTAN A,KASTNER M.Benthic Ba fluxes in the central Equatorial Pacific,implications for the oceanic Ba cycle[J].Earth and Planetary Science Letters,1996,142(3):439-450.
[30]MARTIN W R,BENDER M,LEINEN M,et al.Benthic organic carbon degradation and biogenic silica dissolution in the central equatorial Pacific[J].Deep Sea Research Part AOceanographic Research Papers,1991,38(12):1481-1516.
[31]MILLIMAN J D,TROY P J,BALCH W M,et al.Biologically mediated dissolution of calcium carbonate above the chemical lysocline?[J].Deep Sea Research Part I Oceanographic Research Papers,1999,46(10):1653-1669.
[32]梅西,张训华,郑洪波,等.南海南部120ka以来元素地球化学记录的东亚夏季风变迁[J].矿物岩石地球化学通报,2010,29(2):134-141.
[33]LI C.Deep water carbonate sedimentation of the South China Sea[J].Acta Sedimentologica Sinica,1989,32(6):55-78.
[34]陈晓良,赵泉鸿,翦知湣.南海北部ODP1148站中新世以来的碳酸盐含量变化及其古环境意义[J].海洋地质与第四纪地质,2002,22(2):69-74.
[35]AVERYT K B,PAYTAN A.A comparison of multiple proxies for export production in the equatorial Pacific[J].Paleoceanography,2004,19(4):117-196.
[36]DYKOSKI C A,EDWARDS R L,CHENG H,et al.Ahigh resolution,absolutedated Holocene and deglacial Asian monsoon record from Dongge Cave,China[J].Earth and Planetary Science Letters,2005,233(1):71-86.
[37]梁静之,黄宝琦,董轶婷,等.南海北部MD12-3432站MIS11期以来底栖有孔虫反映的古环境变化[J].地学前缘,2016,23(4):292-300.
[38]成鑫荣,汪品先,黄宝琦,等.南海表层沉积中有孔虫壳体的碳同位素研究及其意义[J].科学通报,2005,50(1):48-52.
[39]WANG L,SARNTHEIN M,ERLENKEUSER H,et al.East Asian monsoon climate during the Late Pleistocene:high-resolution sediment records from the south China Sea[J].Marine Geology,1999,156(1/2/3/4):245-284.
[2]汪品先,闵秋宝,卞云华,等.十三万年来南海北部陆坡的浮游有孔虫及其古海洋学意义[J].地质学报,1986(3):3-13.
[3]WEI G,LIU Y,LI X H,et al.Major and trace element variations of the sediments at ODP Site 1144,South China Sea,during the last 230ka and their paleoclimate implications[J].Palaeogeography,Palaeoclimatology,Palaeoecology,2004,212(3):331-342.
[4]MANGERUD J,SONSTEGAARD E,SEJRUP H P,et al.Correlation of the Eemian(interglacial)Stage and the deepsea oxygen isotope stratigraphy[J].Nature,1979,277(5693):189-192.
[5]BAUCH H A,KANDIANO E.Evidence for early warming and cooling in North Atlantic surface waters during the last interglacial[J].Paleoceanography,2007,22(1):PA1201.
[6]GOLDBER E D,ARRHENIUS G O S.Chemistry of Pacific pelagic sediments[J].Geochimica et Cosmochimica Acta,1958,13(2):153-212.
[7]邵磊,李献华,韦刚健,等.南海陆坡高速堆积体的物质来源[J].中国科学:地球科学,2001,31(10):828-833.
[8]ELDERFIELD H.Tracers of ocean paleoproductivity and paleochemistry:an introduction[J].Paleoceanography,1990,5(5):711-717.
[9]DYMOND J,SUESS E,LYLE M,et al.Barium in deep-sea sediment:ageochemical proxy for paleoproductivity[J].Paleoceanography,1992,7(2):163-181.
[10]KISSEL C,JIAN Z,LEAU H,et al.Shipboard Scientific Party,MD190-CIRCEA cruise report[R]∥Les rapports de campagneàla mer,IPEV,2012,ref:OCE/2012/01.
[11]WANG P X,PRELL W L,BLUM P,et al.26Shipboard Scientific Party,Site 1146[R]∥Proceedings of the ocean drilling program.Texas,scientific results,2000,184:1-101.
[12]ClEMENS S C,PRELL W L.Data report:oxygen and carbon isotopes from Site 1146,northern South China Sea[R]∥Proceedings of the ocean drilling program.Texas,scientific results,2003,184:1-8.
[13]WANG N,HUANG B Q,DONG Y T,et al.The evolution of deepwater dissolved oxygen in the northern South China Sea since 400ka[J].Palaeoworld,2017,27(2):301-308.
[14]CHANG J,BAI Z,SUN Y,et al.High resolution bio-and chemostratigraphic framework at the Frasnian-Famennian boundary:implications for regional stratigraphic correlation between different sedimentary facies in South China[EB/OL].Palaeogeography,Palaeoclimatology,Palaeoecology,2017.(2017-05-13)[2018-05-10].https:∥doi.org/10.1016/j.palaeo.2017.05.09.
[15]刘颖,刘海臣.用ICP-MS准确测定岩石样品中的40余种微量元素[J].地球化学,1996(6):552-558.
[16]乔培军,邵磊,杨守业.南海西南部晚更新世以来元素地球化学特征的古环境意义[J].海洋地质与第四纪地质,2006,26(4):59-65.
[17]NESBITT H W,MARKOVICS G.Weathering of granodioritic crust,long-term storage of elements in weathering profiles,and petrogenesis of siliciclastic sediments[J].Geochimica et Cosmochimica Acta,1997,61(8):1653-1670.
[18]WEI G,LIU Y,LI X,et al.High resolution elemental records from the South China Sea and their paleoproductivity implications[J].Paleoceanography,2003,18(2):1054.
[19]LEI S,LI X,WEI G,et al.Provenance of a prominent sediment drift on the northern slope of the South China Sea[J].Science in China:Earth Science,2001,44(10):919-925.
[20]赵一阳,鄢明才.中国浅海沉积物地球化学[M].北京:科学出版社,1994.
[21]ZHANG C,WANG L,LI G,et al.Grain size effect on multi-element concentrations in sediments from the intertidal flats of Bohai Bay,China[J].Applied Geochemistry,2002,17(1):59-68.
[22]韦刚健,刘颖,邵磊,等.南海碎屑沉积物化学组成的气候记录[J].海洋地质与第四纪地质,2003,23(3):1-4.
[23]YANG S,LI C,CAI J,et al.Geochemical compositions of core sediments in eastern China:implication for Late Cenozoic palaeoenvironmental changes[J].Palaeogeography,Palaeoclimatology,Palaeoecology,2006,229(4):287-302.
[24]NESBITT H W,YOUNG G M.Early Proterozoic climates and plate motions inferred from major element chemistry of lutites[J].Nature,1982,299:715-717.
[25]PEURANIEMI V,PULKKINEN P.Preglacial weathering crust in Ostrobothnia,western Finland,with special reference to the Raudaskyl?occurrence[J].Chemical Geology,1993,107(3/4):313-316.
[26]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.
[27]TAMBURINI F,ADATTE T,FOLLMI K B,et al.Investigating the history of East Asian monsoon and climate during the last glacialinterglacial period(0 140000years):mineralogy and geochemistry of ODP Sites 1143and 1144,South China Sea[J].Marine Geology,2003,201(1/2/3):147-168.
[28]DING Y.Monsoons over China[J].Advances in Atmospheric Sciences,1994,11(2):252-252.
[29]PAYTAN A,KASTNER M.Benthic Ba fluxes in the central Equatorial Pacific,implications for the oceanic Ba cycle[J].Earth and Planetary Science Letters,1996,142(3):439-450.
[30]MARTIN W R,BENDER M,LEINEN M,et al.Benthic organic carbon degradation and biogenic silica dissolution in the central equatorial Pacific[J].Deep Sea Research Part AOceanographic Research Papers,1991,38(12):1481-1516.
[31]MILLIMAN J D,TROY P J,BALCH W M,et al.Biologically mediated dissolution of calcium carbonate above the chemical lysocline?[J].Deep Sea Research Part I Oceanographic Research Papers,1999,46(10):1653-1669.
[32]梅西,张训华,郑洪波,等.南海南部120ka以来元素地球化学记录的东亚夏季风变迁[J].矿物岩石地球化学通报,2010,29(2):134-141.
[33]LI C.Deep water carbonate sedimentation of the South China Sea[J].Acta Sedimentologica Sinica,1989,32(6):55-78.
[34]陈晓良,赵泉鸿,翦知湣.南海北部ODP1148站中新世以来的碳酸盐含量变化及其古环境意义[J].海洋地质与第四纪地质,2002,22(2):69-74.
[35]AVERYT K B,PAYTAN A.A comparison of multiple proxies for export production in the equatorial Pacific[J].Paleoceanography,2004,19(4):117-196.
[36]DYKOSKI C A,EDWARDS R L,CHENG H,et al.Ahigh resolution,absolutedated Holocene and deglacial Asian monsoon record from Dongge Cave,China[J].Earth and Planetary Science Letters,2005,233(1):71-86.
[37]梁静之,黄宝琦,董轶婷,等.南海北部MD12-3432站MIS11期以来底栖有孔虫反映的古环境变化[J].地学前缘,2016,23(4):292-300.
[38]成鑫荣,汪品先,黄宝琦,等.南海表层沉积中有孔虫壳体的碳同位素研究及其意义[J].科学通报,2005,50(1):48-52.
[39]WANG L,SARNTHEIN M,ERLENKEUSER H,et al.East Asian monsoon climate during the Late Pleistocene:high-resolution sediment records from the south China Sea[J].Marine Geology,1999,156(1/2/3/4):245-284.