简介:The26thDecember2004earthquakeofMw9.3isthesecondlargestearthquakeevertohavebeenrecorded.ThisgeneratedatsunamiwhichaffectedseveralAsiancountries.InIndia,theAndaman&Nicobargroupofislands,andcoastalstatesofTamilNadu,AndhraPradeshandKeralawereseverelyaffected.Here,webrieflyprovideanoutlineoftheapproachtakenbyIndiaforanearlywarningsystemformitigationofoceanogenicdisasters.
简介:40Ar-39ArdatingofalbitefromtheMeishanandTaocunirondepositsyieldsplateauagesof122.90±0.16Maand124.89±0.30Ma,andisochronagesof122.60±0.16Maand124.90±0.29Ma,respectively.PhlogopitefromtheZhongshan-Gushanorefieldhasaplateauageof126.7±0.17Maandanisochronageof127.21±1.63Ma.Analysisofregionalgeodynamicevolutionofthemiddle-lowerYangtzeRiverregionsuggeststhattheporphyryirondepositswereformedasaresultoflarge-scalelithospheredelaminationandstrongsinistralstrike-slipmovementoftheTanchengLujiangfaultzone.Thecopper,molybdenumandgolddepositsysteminthemiddle-lowerYangtzeRiverregionwasformedduringthestresstransitionperiodoftheeasternChinacontinent.
简介:Byusingthe40Ar-39ArchronologicalmethodtodateK-feldsparfromK-feldspargraniteintheQiaohuotecopperdistrict,theauthorsobtainedaplateauageof274.78±0.44Maandanisochronageof272.7±3.0Ma.BecausethereisnotectonicdeformationoverprintedorhydrothermalalterationintheK-feldspargraniteintrusionafteritsemplacement,the40Ar-39AragerepresentsthecrystallizationageofK-feldsparinK-feldspargranite,i.e.thelatecrystallizationageoftheK-feldspargraniteintrusion,whichindicatesthattheK-feldspargraniteformedintheintraplateextensionalstageduringtheEarlyPermian.Moreover,basedonthespatialrelationshipbetweentheK-feldspargraniteintrusionandcopperorebodies,variationsofcopperoregrade,REEcharacteristicsofK-feldspargraniteandcopperores,andHandOisotopiccompositionsoffluidinclusionsincopperores,themetallogenesisoftheQiaohuotecopperdepositisdirectlyrelatedtointrusiveactivitiesoftheK-feldspargranite,andthusthecrystallizationageofK-feldsparinthegraniteapproximatelyapproachesthemetallogenicepochoftheQiaohuotecopperdeposit.