简介：Theresultsof118REEanalysesofLi-FgranitesfromSouthChinaandothercountriesindicatethattherearethreevariationtypesofREEpatterncurveswithdifferentevolutiontrendsfromearlytolatestagesofLi-FgranitecomplexoffromlowertoupperpetrofaciesoftheLi-Fgranitebody;(1)thedecreasing,(2)theincreasing,and(3)thesaltatoryvariationtypes.Thefirstvariationtypeiscalledthepositiveevolutiontype,attributedtocrystallizationdifferentiation.Thesecondiscalledthereversionevolutiontype.whichrepresentsliquidsegreationdominatedbyvapor-liquiddistillation.Thethirdiscalledthesaltatoryvariationtype,whichisformedfromliquidsegregationdominatedbyimmiscibilty,Therefore,theindicaticesofliquidsegregationdominatedbyimmiscibilityarethesaltatoryvariationtypeofREEpatternevolutionandtheseparationofthemainevolutiontrendlineseitherfromthesub-evolutiontrendlinesorfromthecompositionpointsofLi-FgranitesinthediagramsofREE-(La-Yb)NandLa/Sm-La,Theindicatricesofliquidsegregationdominatedbyvapor-liquidfractionaldistillationarethereverstionevolutiontypeofREEpatterncurvesandthemainevolutiontrendlinesofLi-Fgranitesdirectingtotheupperright-handontheREE-La/Yb)NandLa/Sm-Ladiagrams.

简介：Li-Fgranitesallovertheworldcanberepresentedbythreeendmembers,i.e.,theNa-richongonite(O),theK-richxianghualingite(X)andtheSi-richtopazite(T),Charactersandcriteriaarepresentedfortheseend-mnemberrocks,VerticalzoninginLi-Fgranites,asreflectedbyincreasingnormativeQandC(corundum)anddecreasingALK(K2O+Na2O)withincreasingcontentoffluorine,canbeexplainedusingthethree-end-memberschemeintermsofpetrochemistryandnorms.Consideringthedifferenceinmeltstructure,visocosityanddensitybetweentheendmembers,incouplewiththeregulartiesthatgoverntheNa-KandSiALKsegregationknownfromfieldevidenceandexperiments,itissuggestedthatthethreeendmembersmayhaveresultedfromliquidsegregation(immiscibility)ratherthanfromcrystalfractionationascommonlybelieved.

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

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。