摘要
TheZhoukoudianstockinBeijingisaconcentriczonedcomplexintrusivebodyformedbytwosuccessiveintrusions.Quartz-dioriteformedbythefirstintrusionisscatteredsparselyonthemarginsofthebody,whilegranodioriteresultingfromthesecondintrusionconstitutesthemainpartoftheintrusion.Itexhibitsthreedistinctpetrographiczonesmacroscopically,andischemicallycharacterizedbyenrichmentofhigh-temperaturecomponents,suchasMg,Ca,Sc,Ti,Cr,Mn.FeandCo,onitsborderandmerelyslightenrichmentofsomelow-temperaturecomponents,suchasNaandSi,initscentralpart.Aseriesofstructuralfeaturesindicatethatthedeformationoftheintrusionandthermo-metamorphicrocksbecomesweakerwithanincreaseofdistancefromthecontact,andthattheintrusivebodyisaproductofballooningorinflatingdiapiricemplacement.Basedoncalculationsofthedensity,viscosityandyieldstrengthofmagmaandthereasonablediffusionconstantsandoxygenisotopicdata,themechanismofthecompositionalzonationofthemajorpartofthestockisdiscussed.ItisconsideredthattheSoreteffect,combinedwithdouble-diffusiveconvection,canexplainthecompositionalzonationoftheintrusion.Calculationoftheascentratesofmagmashowsthatsuccessiveupwellingofmagmagotfasterandfasterwiththeprogressoftime.
出版日期
1989年02月12日(中国期刊网平台首次上网日期,不代表论文的发表时间)