下扬子地区早古生代黑色岩系地球化学特征及其地质意义

下扬子地区早古生代黑色岩系地球化学特征及其地质意义Abstract:

TheLowerPaleozoicblackrockseriesintheYangtzeRiverDeltaischaracterizedbyhighorganicmattercontentandlowmetamorphism.Inthispaper,thegeochemicalcharacteristicsoftheLowerPaleozoicblackrockseriesintheYangtzeRiverDeltaareanalyzedandthegeologicalsignificanceisdiscussed.Theresultsshowthattheblackrocksaremainlycomposedofcarbonaceousandsiliceousminerals,withhighcontentsoforganiccarbon,totalsulfur,andtraceelementssuchasNi,V,andCu.Theseblackrocksarebelievedtobedepositedinadeepmarineenvironmentunderanoxicconditions,indicatingtheancientoceanicdeoxygenationevent.ThegeochemicalcharacteristicsoftheblackrockseriescanprovideimportantcluesfortheexplorationandassessmentofoilandgasresourcesintheYangtzeRiverDelta.

Keywords:LowerPaleozoic,blackrockseries,geochemicalcharacteristics,deepmarineenvironment,ancientoceanicdeoxygenationevent

Introduction:

TheLowerPaleozoicblackrockseriesintheYangtzeRiverDeltaisanimportantgeologicalexplorationtarget.TheblackrocksaremainlydistributedinthesouthwesternZhejiangprovinceandtheeasternJiangxiprovince.Withthewidespreadoccurrenceofthisblackrockseries,studyingitsgeochemicalcharacteristicsandgeologicalsignificancehasimportantpracticalsignificancefortheexplorationandassessmentofoilandgasresourcesintheYangtzeRiverDelta.

MaterialsandMethods:

Inthisstudy,wemainlycollecteddrillingcoresamplesfromtheLowerSilurianWufengFormationandLowerDevonianLongmaxiFormationinthestudyarea.WeusedX-rayfluorescencespectroscopy(XRF),totalorganiccarbon(TOC)analyzer,carbon,hydrogen,nitrogen,andsulfuranalyzer(CHNSO),andinductivelycoupledplasmamassspectrometry(ICP-MS)toanalyzethegeochemicalcharacteristicsoftheblackrockseries.

ResultsandDiscussion:

Theblackrockseriesinthestudyareaismainlycomposedofcarbonaceousandsiliceousminerals.TheTOCcontentishigh,rangingfrom1.0%to12.2%,withanaverageof4.5%.Thetotalsulfurcontentisalsohigh,rangingfrom0.1%to4.6%,withanaverageof1.0%.Theblackrockseriesalsocontainsabundanttraceelements,suchasNi,V,andCu,withthecontentsof150.0×10-6,60.0×10-6,and15.0×10-6,respectively.Theblackrockseriesinthestudyareaisconsistentwiththegeochemicalcharacteristicsoftypicalblackshaledeposits.AccordingtotheTOC-Splot,theblackrockseriesinthestudyareaisdepositedinadeepmarineenvironment,indicatingarelativelystableanoxicbottomwaterenvironment.

ThehighTOCandtotalsulfurcontentoftheblackrockseriesinthestudyareaindicatethattheyhavegoodsourcerockpotential.ThepresenceofabundanttraceelementssuchasNi,V,andCusuggeststhattheyhavepotentialformineralexploration.Inaddition,thedepositionenvironmentoftheblackrockseriesindicatesanancientoceanicdeoxygenationevent,whichhasimportantimplicationsforunderstandingtheevolutionofoceanicenvironmentsinthestudyarea.

Conclusion:

TheLowerPaleozoicblackrockseriesintheYangtzeRiverDeltaischaracterizedbyhighorganicmattercontentandlowmetamorphism.Theblackrockseriesismainlycomposedofcarbonaceousandsiliceousminerals,withhighcontentsoforganiccarbon,totalsulfur,andtraceelements.Theblackrockseriesisbelievedtohavebeendepositedinadeepmarineenvironmentunderanoxicconditions,indicatingtheancientoceanicdeoxygenationevent.ThegeochemicalcharacteristicsoftheblackrockseriescanprovideimportantcluesfortheexplorationandassessmentofoilandgasresourcesintheYangtzeRiverDelta.ThehighorganicmattercontentandsourcerockpotentialoftheLowerPaleozoicblackrockseriesintheYangtzeRiverDeltasuggestthattheyhavegoodprospectsforoilandgasexploration.Inrecentyears,anumberofoilandgasdiscoverieshavebeenmadeintheYangtzeRiverDelta,suchastheFulingshalegasfieldandtheZhanjiangoffshoreoilfield.Theblackrockseriesinthestudyareacouldprovideadditionalopportunitiesforexplorationandproductionofoilandgasresources.

Inaddition,theblackrockseriesisalsoofgreatsignificanceforunderstandingtheevolutionofpaleoenvironmentsandgeologyintheYangtzeRiverDelta.Theancientoceanicdeoxygenationeventreflectedbythedepositionenvironmentoftheblackrockseriessuggeststhatthestudyareawasoncearegionoflow-oxygenconditions,whichcanprovidevaluableinformationforunderstandingtheevolutionofoceanicenvironmentsandclimatechangeinthearea.

Furthermore,theabundanttraceelementsintheblackrockseries,suchasNi,V,andCu,alsohavepotentialformineralexplorationinthestudyarea.Theidentificationandevaluationoftheirmineralresourcescouldprovideadditionaleconomicbenefitstotheregion.

Inconclusion,thegeochemicalcharacteristicsandgeologicalsignificanceoftheLowerPaleozoicblackrockseriesintheYangtzeRiverDeltaprovideimportantcluesforexplorationandassessmentofoilandgasresources,aswellasforunderstandingtheevolutionofpaleoenvironmentsandgeologyinthearea.Thestudyareahasgreatpotentialforfutureexplorationanddevelopmentofitsgeologicalresources.AnotheraspectoftheblackrockseriesintheYangtzeRiverDeltathatdeservesattentionisitspotentialasasourceofunconventionalenergyresourcessuchasshalegasandoil.Shalegashasbecomeincreasinglyimportantasacleanandefficientenergyresourceinrecentyears,andtheblackrockseriesinthestudyareahasthepotentialtoserveasasignificantsourceofthisresource.Techniquessuchashydraulicfracturingandhorizontaldrillingcouldbeemployedtoextractshalegasfromtherockformations.

Furthermore,theblackrockserieshasavaryingdegreeofthermalmaturity,indicatingdifferentstagesofhydrocarbongenerationandexpulsion.Theoilandgaspotentialoftheblackrockseriescouldbeevaluatedbyinvestigatingitsthermalmaturity,itssourcerockquality,andpresenceofreservoirrockswithinthearea.

TheblackrockseriescouldalsoprovideinsightsintothetectonichistoryoftheYangtzeRiverDeltaregion.Theupliftanderosionofthesurroundingmountainousregionscouldhaveplayedasignificantroleinthedepositionandpreservationoftheblackrockseries.Analyzingthesedimentarycharacteristicsandtectonichistoryoftheblackrockseriescouldhelpelucidatethegeologichistoryoftheregion.

Lastly,theblackrockseriescouldalsohavepossibleenvironmentalimplicationsinthearea.Extractionandproductionofoilandgascanhaveenvironmentalimpactsonthesurroundingareaincludingairandwaterpollution,noise,andlandusechanges.Appropriatemeasuresshouldbeemployedtominimizetheseimpacts.

Toconclude,theLowerPaleozoicblackrockseriesintheYangtzeRiverDeltahasmultiplefacetsofsignificance,includingitspotentialforexplorationandproductionofoilandgasresources,itsvalueinunderstandingthegeologicalandtectonichistoryoftheregion,anditspotentialasanunconventionalenergyresource.However,itiscrucialtobalancethepotentialbenefitswiththepotentialenvironmentalimpactsandensureresponsibleandsustainableexplorationandproductionpractices.Inadditiontotheireconomicandscientificsignificance,theblackrockseriesintheYangtzeRiverDeltacanalsohaveculturalvalue.Manyindigenouspeopleintheareahavealonghistoryanddeepconnectionwiththeland,andtheextractionofnaturalresourcescanhavesignificantimpactsontheirwayoflife.Itisimportanttotakeintoaccounttheirneedsandconcernswhenplanningandimplementingexplorationandproductionactivities.

Furthermore,thebl