简介：Itisgenerallyacceptedthatthecompositionsandpropertiesofsoilorganicmatter（SOM）arein?uencedbymanyfactors.InordertorevealtheeffectsofsoiltextureoncharacteristicsanddynamicsofSOManditssub-fraction,humicacid（HA）,alongtwosoilpro?les,ayellowsoilpro?leandapurplishsoilpro?le,underthesameclimateandvegetationconditionsweredetermined.Resultsindicatethatthedecompositionandhumi?cationdegreesofSOMandHAofthepurplishsoilsarehigherthanthoseofthecorrespondingyellowsoilsindicatedbyA/O–AratiosofHAs,TOCsandHAyieldsofbulksoilsamples,nevertheless,thedevelopmentdegreeofthepurplishsoilislowerthanthatoftheyellowsoil.ThevariationsofE4/E6ratiosofHAsalongthesoilpro?lesindicatetheoverallmolecularsizesofHAsdecreaseddownwardalongthesoilpro?les.A/O–AratiosofHAsdecreaseddownwardalongboththesoilpro?lesindicatethathumi?cationprocessesdecreasedownwardalongboththesoilpro?les.LeachingofSOMshowssigni?canteffectsonthedistributionandcharacteristicsofHAsintheyellowsoilpro?lebutthepurplishsoilpro?le,whichisconsistentwiththehigherhydrophobicityofHAsinpurplishsoils,showsthatthedistributioncharacteristicsofSOMalongthesoilpro?lesareacomplexresultofthecombinationofsoiltextureandcharacteristicsofSOMitself.TheremarkablydifferentsandcontentsareconcludedtentativelyasoneofreasonstothedifferentdistributionsanddynamicsofHAsalongthesoilpro?les,however,toprofoundlyunderstandtheevolutionandtransportofSOMalongsoilpro?lesneedsmoreresearches.

简介：Thecoal-bearingstrataoftheUpperPaleozoic(fromtheTaiyuanFormationtothelowermemberoftheShanxiFormation)arethemostimportantunitsthathavehighgasproductionintheDaniudigasfield,whichisatypicaltight-sandstonereservoirwithhighheterogeneityintheOrdosBasin,China.Basedonanintegratedinvestigationofwelllogs,cores,SEMand3-Dseismicdata,wedelineatedthesedimentaryfaciesofthecoal-bearingstrataanddividedthesuccessionintosequencedstratigraphicunitsofdifferentdepositionalsystems.AsedimentaryhiatuswasdocumentedforthefirsttimeinthestudyareaandformsthesequenceboundarybetweentheLowerPennsylvanianCarboniferousTaiyuanFormation(Ct1)andtheUpperPennsylvanianCarboniferousTaiyuanFormation(Ct2).Thecoal-bearingstratainCt1areindicativeofabarriercoastaldepositionsystem.Tidalchannelsareidentifiedbytheirfine-grained,cross-stratifiedcharacter.Thesandsinthetidalchannelsarewellsorted,andthequartzcontentisabove95%.Thecoalbedlocatedbesidethesandstoneisthoughttobealagoon.Gas-bearing,coarse-grainedsandstoneinthecoal-bearingstrataspanningfromtheCt2tothelowermembersoftheShanxiFormation(P1s)isinterpretedasafluvial-dominatedbraideddeltathatisdividedintofourthird-ordersequences.Thecoal-bearingstrataarecomposedofsandstone,mudstoneandcoalbedfrombasetotopineachsequence.Braided-riverdepositsformthelowstandsystemtract(LST)withineachsequence.Ashelfandlakedepositionalenvironmentcontainingdarkgraymudstoneformsthetransgressivesystemstract(TST).Thehighstandsystemstract(HST)depositsformtheswampcoalbedineachsequence.