简介：ThestrongadaptabilityofBroussonetiapapyrifera(L.)Vent.tolowphosphorus(P)conditionscanbeattributedtothelargeamountofroot-exudedorganicacidsandthehighef?ciencyofPextraction.However,microelementcontentsarein?uencedbylow-Pstress,andtheireffectsonthephotosyntheticcapabilityofB.papyriferaremainunknown.Inthisstudy,weinvestigatedtheeffectsoflow-Ptreatmentonnetphotosyntheticrate(P_N);chlorophylla?uorescence(ChlF)characteristics;andFe,Mn,Cu,andZncontentsofB.papyriferaandMorusalbaL.seedlings.ResultsshowthatB.papyriferaexhibitedbetterphotosyntheticcapabilityundermoderatePde?-ciency(0.125,0.063,and0.031mmol/LPtreatments),whereasthephotosyntheticcapabilityofM.albadecreasedundermoderateandseverePde?ciency(0.016and0mmol/LPtreatments).UndermoderatePde?ciency,thedecreaseinCuandZncontentsinB.papyriferawaslowerthanthatinM.alba.UnderseverePde?ciency,aconsiderabledecreaseofphotosyntheticcapabilityinB.papyriferaandM.albawasassociatedwithlowCuandZncontents.ThePNofthetwoMoraceaespeciesexhibitedabettercorrelationwithCuandZncontentsthanwithFeorMncontent.Pde?ciencycouldnotonlydecreasecyclicphotophorylationandphotosyntheticef?ciency,butcouldalsoaffectthestabilityofthylakoidmembranestructureandelectrontransportef?ciencybyin?uencingthecontentsofCuorZn,therebyaffectingphotosynthesis.

简介：Metalgrainsinstonymeteoritesarerelativelymovableduringthermalnetamorphism(Wood,1967;XieandWang,1979;Xie,1986).InviewofthefactthattheJilinmeteoriteisthelargestintheworldknownuptonow,itsmainbodyweighing1770kganditstotalvolumeamountingto117×93×84cm^3,ade-tailedinvestigationintosuchahugemeteoritebodywouldundoubtedlyprovideuswithalotofcluesandinformationvaluableinthestudyofthebehaviorofFe-Nimetalduringthermalmetamorphismofmeteorites.OurrecentinvestigationhasrevealedthatduringthermalmetamorphismoftheJilinchondirtefineFe-Nimetalparticlesmigratedeasilybydiffusioninsolidstate,andsubsequentlyaggregatedintometalnodulesabout5-10mminlength,andthelargestnodulewefoundis30mminsize(Photo1).Inthispaperwepresentsomenewresultsofourstudyconcerningthemigra-tionandconcentrationofFe-NimetalintheJilinchondriteonthebasisofop-tical,SEMobservationsandhigh-temperature-highpressureaswellasshockloadingexperiments.

简介：这篇论文在Guiyang的地表的土壤描述象Cu和Zn那样的重金属污染物质的环境联盟者geochemical特征，GuizhouProvince的首都的城市。在土壤和geochemical标准的重金属的基线集中被建立了在环境上区分自然或人工的影响。用统计上分析方法，我们在Guiyang(18.8mg/kg)建立了Cu的基线，土壤(超过68.4mg/kg)可以承受Cu污染。Zn的数据是46。3mg/kg并且112。0mg/kg。Geoaccumulation指数分析显示有sufferednon污染到的地表的土壤为38%，38%，和22%的Cu帐户为中间污染中间污染，并且仅仅对严重污染中间污染的2%between。承受了Zn的非污染tomid污染的地表的土壤占41%，50%，和7%为中间污染，并且仅仅2%betweenmid污染到严重污染。Cu污染的最大的度在Guiyang的surficials油是5.09。没为53承受Cu污染报道的地表的土壤。2%。Cu的全部的污染度是稍微超过零。Guiyang的地表的土壤因此承受了slightCu污染。Zn污染度的最大的价值是2。85在地表的土壤ofGuiyang。77。8%地表的土壤还没承受了任何Zn污染。Zn的全部的污染度是不到零。在Guiyang的地表的土壤因此从Zn的污染是免费的。

简介：Understandingtheeffectsoforganicacids（OA）onthetransformationofFeandMntosurfacewaterfromtheweatheringcoalgangueisofgreatbene?ttoriskassessmentandremediationstrategiesforcontaminatedwaterandsoil.BasedontheinvestigationonsurfacewaterinthecentralcoaldistrictsoftheGuizhouProvince,18watersampleswerecollectedforheavymetalanalysis.TheresultsindicatedthatthepHvalueofsurfacewaterislow（3.11–4.92）,andFeconcentration(1.31–5.55mgL-1)andMnconcentration(1.90–5.71mgL-1)were,onaverage,10.86and34.33timesthelimitofSurfaceWaterQualityStandards,respectively.InordertoevaluatetheeffectsoftheOAonthedissolutionofFeandMnfromtheweatheringcoalgangue,columnelutionandbatchleachingexperimentswereconducted.Theresultsshowthatthelowmolecularweightoforganicacids（LMWOAs,i.e.,oxalic,tartaric,malicandcitricacids）andfulvicacidssigni?-cantlyacceleratedthedissolutionofFeandMn;inaddition,whentheconcentrationofOAreached25mmolL-1,theconcentrationsofFe,andMnwere1.14–67.08and1.11–2.32timesashighasthosein0.5mmolL-1OA,respectively.Furthermore,themigrationofFeandMnwassigni?cantlyin?uencedbythepHandEh,especiallyforFe;theionMnwasdissolvedfromtheganguemoreeasilythantheionFeinthecolumnleaching,whichwascontrarytotheresultsofbatchleaching.

简介：Ba同位素由于具有在低温环境中分馏的特性,相比放射性同位素与微量元素,可以更好地示踪地球深部动力学过程中的再循环物质。研究表明沉积物与蚀变洋壳具有明显不同的Ba同位素组成（沉积物富集来自重晶石的Ba）,使得Ba同位素成为研究表层与地幔储库间物质交换的有力工具。

简介：

简介：本文以上海市苏州河沉积物为研究对象，采用Tessier形态分析法研究了沉积物中重金属元素Zn、Cu和Hg的含量变化与形态分布，初步探讨了沉积特点，为苏州河底泥的进一步治理提供了参考。结果表明，样品中Zn、Cu、Hg的含量均接近或高于生物有影响水平；Zn、Cu分别主要存在于有机态和Fe-Mn氧化物态中，可交换态中含量较少；Zn、Cu、Hg含量随沉积物深度的变化为：沉积物表层重金属含量较低并略有起伏，中部较高，底层较低。

简介：为探讨沁水盆地东部Y井煤系页岩的元素地球化学特征,对下二叠统山西组、太原组的煤系页岩进行了系统采样,并应用电感耦合等离子体质谱法(ICP-MS)对18个煤系页岩样品的微量及稀土元素进行了分析测试。结果表明,煤系页岩的Sr、Sr/Ba、V/(V+Ni)、Ceanom等地球化学指标的垂向变化,反映了从太原组到山西组沉积时期,水体古盐度整体逐渐降低的还原环境;物源主要来自盆地北邻阴山古陆前寒武纪花岗岩、麻粒岩及各时代侵入岩,源区构造背景主要为与大陆岛弧相关的活动大陆边缘。

简介：岩浆Cu-Ni-PGE硫化物矿床形成的重要过程是硫化物熔体的熔离,而关键在于成矿岩浆中硫的过饱和。判断岩浆Cu-Ni-PGE硫化物矿床中硫来源最直接有效的方法就是研究其硫同位素特征。当矿床的硫同位素值超出了地幔硫同位素的组成范围,揭示了壳源硫的混入。如果矿床硫同位素值δ^34S落入地幔值的范围内,则需要结合围岩硫同位素组成、并考虑岩浆房中是否发生了硫同位素交换反应来进一步判断是否有围岩硫的加入。异常的Δ^33S值主要出现在太古宙沉积硫化物中,利用δ^34S与Δ^33S相结合可识别样品中是否存在太古宙岩石中来源的硫;然而,一些太古宙岩石中硫化物Δ^33S值也可以在0‰附近;在一些后太古宙岩石的硫化物中也发现了异常的Δ^33S值;因此在根据Δ33S值来判断S是否来源于太古宙岩石时应谨慎。仔细测定围岩和潜在的混染源的硫同位素组成对于准确评价岩浆Cu-Ni-PGE硫化物矿床中S的来源是非常关键的。硫同位素和其他同位素如镍同位素、铜同位素、铁同位素相结合也许对于认识岩浆Cu-Ni-PGE硫化物矿床中成矿物质来源及成矿岩浆演化过程能够提供新的思路。

简介：Icecoreδ18OrecordefromtheNo.aglacierattheheadoftheUrumqiRiverwereusedocharacterizetherelationshipbetweenδ18Oandcontemporaneoussurfaceairtemperature(Ta)nearbytheDaxigouMeteorologicalStation(3539mabovesealevel,-2kmawayfromtheicecoredrillingsite),Althoughtheicecorerecordsofannuallyaveragedδ18Oarepositivelycorrelatedwithconemporaneoussurfaceairtemperature,especiallysummerairtemperature,thecorrelationislesssignificantthanthatfortheprecipitationsamplesduetodepositionalandpost-depositionalmodificationprocesses,However,theClimatologicalsignificanceoftheicecorδ18Orecordscanbestillpreservedtoacertaindegree,whichmoghtextendtheapplicationofhighaltitudeandsub-tropicalicecoreδ18Orecordstopaleoclimatereconstruction.

简介：

简介：　　岩浆铜镍硫化物矿床是目前Ni和铂族元素(PGE)的主要来源,然而,不同矿床Cu、Ni和PGE的品位和比例却往往存在较大的变化,但关键控制因素远未弄清.……

简介：TheDachangtin-polymetallicdistrict,Guangxi,China,isoneofthelargesttinorefieldsintheworld.Bothcassiterite-sulfideandZn-CuskarnmineralizationarehostedintheMid-UpperDevoniancarbonate-richsedi-mentsadjacenttotheunderlyingCretaceousLongxianggaigranite（91-97Ma）.TheLamoZn-CudepositisatypicalskarndepositinthedistrictandoccursatthecontactzonebetweentheUpperDevonianlimestoneandthegranite.Theoremineralsmainlyconsistofsphalerite,arsenopyrite,pyrrhotite,galena,chalcopyrite,andminormolybdenite.However,theageofmineralizationandsourceofthemetalsarenotwellconstrained.Inthisstudy,weusethemolybdeniteRe-Osdatingmethodandin-situPbisotopesofsulfidesfromtheLamodepositforthefirsttimeinordertodirectlydeterminetheageofmineralizationandthetracingsourceofmetals.SixmolybdenitesamplesyieldedamoreaccurateRe-Osisochronageof90.04-1.1Ma（MSWD--0.72）,whichismuchyoungerthanthereportedgarnetSm-Ndisochronageof95±11MaandquartzfluidinclusionsRb-Srisochronageof99±6Ma.ThisageisalsointerpretedastheageofZn-Cuskarnminer-alizationintheDachangdistrict.Further,inthisstudywefoundthatin-situPbisotopesofsulfidesfromtheLamodepositandfeldsparsinthedistrict＇sbiotitegraniteandgraniticporphyrydikeshaveanarrowrangeandanoverlapofPbisotopiccompositions（206pb/204pb18.417-18.594,207pb/204pb=15.641-15.746,and208pb/204pb=38.791-39.073）,suggestingthatthemetalsweremainlysourcedfromCretaceousgraniticmagma.

简介：认识驱动太古代地壳形成和分异的地球动力学过程及垂向构造过程（地幔上涌）相对于水平构造过程（如俯冲作用）的重要性,是地球科学领域的一个根本性的、高度争议的科学问题。由于O同位素可在岩石和液态水的低温反应过程中发生分馏,其为精确限定上地壳岩石的循环和再造提供了一个强有力的研究工具。近日,《地质学》杂志报道了西奥大学JohannesHammerli团队关于上述问题的最新研究成果。