摘要
Researchsamplesweretakenfromanancientgravelstratumwhichisnotonlyarepresentativesoillayeralongthemiddle-lowerreachesoftheYangtzeRiverinEastChina,butalsooneoftheprimaryNeozoicstratainNanjingdistrict.Locatedmostlyonthesecondandthirdterraces,theancientgravelstrataformedthegeomorphiclandscapesofterraceandstep.Theywerecomplexinconstitution,variedwidelyinstability,ofmultiplesources,locallyderived,andassociatedwithbraidedstreamsinthedepositionenvironment.ACIPW(Cross,Iddings,PirssonandWashington)methodmodifiedbytheauthorwasusedtoanalyzethesoi-rock-formingmaterialsoffinergrains(lessthan2mminsize)oftheancientgravelstratum.Resultsoftheanalysisshowedthatthesandygrainswerecomposedofapatite,ilmenite,potassiumfeldspar,plagioclase,enstatiteandfreequartz,theclaymainlyofkaolinite,andthecementofacombinationofsilicon,aluminumandironataratioof46:44:10.Inthesoil-rock-formingprocesses,includingcompactionalsolidification,water-stableilluviation-cementation,homogeneousovergrowthandsoon,theloosesoil-rock-formingcomponentsgraduallychangedintoconsolidatedsoilandfurthertotheearlystageoflithification.Meanwhile,fromtheanalysis,wefoundthattheancientgravelstratumhadbeenprotectedbytheoverlyingXiashuloessorbasaltandtheoverloadingresultedinoverconsolidatedstrata.ThemodifiedCIPWmethodwasapplicableandeffectiveforsemi-quantitativeanalysis.
出版日期
2001年03月13日（中国期刊网平台首次上网日期，不代表论文的发表时间）
