学科分类
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5 个结果
  • 简介:0IntroductionTheJapaneseIslandsconsistoffivevolcanicarcs(Fig.1).TheNorth-EastandSouthWestJapanarcstogetherformtheHonshuarc,towhichtheKurilearcjoinsatHokkaido,whereastheIzu-MarianaarcjoinsatIzu-FossaMagna,andtheRyukyuarcjoinsatKyushu.Theseregionswherevolcanicarcsconverge,aretermed'islandarcjunctions'.

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  • 简介:1.ObjectivesKeeryinraremetaloredistrictislocatedattheintersectionofMarkam,JinchuanandRangtangcounties.Morethan1000pegmatitedykesareassociatedwiththeKeeryingranitepluton.Thesepegmafitedykesarethemajorsourceofindustrialspodumeneorebodies.Basedonthepreviousstudies,wechoseKeeryinraremetaloredistrictasthekeytargetareaforgeologysurvey.Inthisstudy,wediscoveredsixpegmatitelithiumveinsintheSizemuzudistrictoftheKeeryin.Moreover,westudythedistributionofregionaloredepositsandmetallogeny,delineateprospectingtargetandevaluatethemineralizationpotentialofLithium.

  • 标签: DISCOVERY PEGMATITE LITHIUM VEINS Sizemuzu DISTRICT
  • 简介:ObjectivesToassessedthefeasibilityandeffectivenessofelectrophysiologicalmappingofpulmonaryveinswithacircumferential10-electrodecatheterandradiofrequencycatheterablationtherapyforpatientswithparoxysmalatrialfibrillation.BackgroundStandardmappingandablationoffocalsourcesofatrialfibrillationareassociatedwithverylongproceduretimesandlowefficacy.Mappingandablationpulmonaryveinsguidewithacircularcathetercouldovercometheselimitations.Methods16patients[male11,female5,meanage(51±14.5)years]withparoxysmalatrialfibrillationrefractorytoantiarrhythmicdrugswereincludedinthisgroup.Acircumferential10-electrodecatheterwasusedtopulmonaryveinmappingduringsinusrhythmorCSdpacingtodeterminetheoriginofatrialprematurecontractions.Whentheablativetargetpulmonaryveinwasfound,thepulmonaryveinpotentials’distributionandactivationwereassessmentpulmonaryveins’ostialablationwasperformedattheseg

  • 标签: ATRIAL FIBRILLATION Pulmonary vein CATHETER ablation
  • 简介:TheYangshangolddepositisasuper-largefine-graineddisseminatedgolddepositlocatedinsouthernGansuProvince.ItsmetallogenicagehasbeendeterminedbyusingthecathodoluminescenceimageandionprobeU-Pbdatingtechniques.Itisfoundthatzirconsfromquartzveinletofthefine-graineddisseminatedgoldoreshowcharactersofmagmaticoriginwithprismidiomorphism,oscillatoryzoninganddominantTh/Uratiosof0.5-1.5.Threemainpopulationsofzirconsareobtained,givingaverage206pb/238Uagesof197.6±1.7Ma,126.9±3.2Maand51.2±l.3Marespectively.ThefirstagecorrespondstotheK-Arageoftheplagiogranitedike,whilethelattertwoagesindicatethatburiedCretaceousandTertiaryintrusivesexistintheorefield,suggestingthattheYangshangolddepositwasgeneticallyrelatedtothethreemagmatichydrothermalactivities.Bycontrast,zirconsfromcoarsegold-bearingquartzveinintheminingareaaremucholderthanthehostrock,indicatingthattheveinwasformedearlierandwasnotcontaminatedbylatermagmaticfluids.ItisconcludedthatthecouplingofmultiperiodichydrothermalactivitiesintheminingareahascontributedalottomineralizationoftheYangshangolddeposit.

  • 标签: 散布型金矿 石英矿脉 SHRIMP 甘肃 阴极发光图像
  • 简介:TheShihugolddeposit,situatedintheTaihangMesozoicorogenoftheNorthChinaCraton(NCC),ishostedbyductile-brittlefaultswithinArcheanmetamorphiccorecomplex.Thedepositischaracterizedbygold-bearingquartz-polymetallicsulfidesveins.TheMapenggranitoidsstockandintermediate-basicdikesintrudedthemetamorphicbasementrocks,andarespatiallyrelatedtogoldmineralization.Detailedlaserablationinductivelycoupledplasmamassspectrometry(LAICP-MS)U-Pbzirconagesofthegraniticrocks,dykesandmineralizedquartzveinsinthestudiedarearevealitsmagmaticandmineralizedhistory.Themineralizedquartzveinscontaininheritedzirconswithagesofabout2.55Gaand1.84Ga,probablycomingfromthebasement.ThesetwoPrecambrianeventsarecoevalwiththoseinotherpartsoftheNCC.TheMapenggranitoidstock,thelargestintrusioninthearea,wasemplacedatca.130Ma,andiscoevalwithmagmaticzirconpopulationsfromdioritesandquartzdioritepophyritesinthesameregion.Theca.130MamagmatismandgoldmineralizationweremostlikelyrelatedtoanunderplatingeventthattookplaceintheTaihangorogenatLateMesozoic.Thetimingofgoldmineralizationwithrespecttofelsicmagmatismintheareaissimilartothoseobservedinothermajorgold-producingprovincesintheNCC.ThisepisodeissimultaneouswiththoseintheeasternmarginofNCC,indicativeofawidespreadlateYanshanianmetallogeniceventthatwasaresponsetotheEarlyCretaceouslithosphereintheeasternNCC,inwhichthemesothermalgolddepositswereformedfromsimilartectono-magmaticenvironments.

  • 标签: 锆石U-PB同位素年龄 ICP-MS 金成矿作用 花岗岩类 激光烧蚀 构造意义