简介:
简介:<正>About20travelersandIwerecrammedonabusonthewindingroadbetweenBaoshanAirport,about530kilometersawayfromKunming,capitalofSouthwestChina’sYunnanProvince,andTengchong.WewereonourwaytoseesomedormantvolcanoesaroundTengchong,aplacewell-knownforitsuniquegeographicsceneryinwesternYunnan.Itwasabrightdaywithasteadybreeze,idealforalongtrip.Theshuttlebusrattledconsiderablyasitracedalongthedustyroadwith
简介:Hydrothermalchimneyisaproductofhydrothermalactivityontheseabed.ChimneysamplesdredgedfromJadehydrothermalareainIzenadepressionoftheOkinawaTrough,arecharacterizedbyrelativelyenrichedlightrareearthelements(LREE)andstronglypositiveEuanomalies.87Sr/86Srand143Nd/144Ndofthesesamplesareexactlybetweenthoseofseawaterandofacidicpumice,averagedat0.708928and0.512292,respectively.ThesecharacteristicsimplythatthemainsourceofhydrothermalsulfideatJadeareaispossiblytheundersurfaceacidicrocks.Themineralizingmechanismcanbesummarizedasfollows:LargeamountofmineralizedmaterialwouldbeleachedoutandLREEenrichedhydrothermalsolutionwouldbesubsequentlyproducedasaresultofthermo-chemicalexchangereactionbetweenacidicvolcanicrocksandheatedseawaterthatpenetratedinadvancefromupperwatermass.ThespurtingoutfromtheseabedandquicklycrystallizingintheseawaterofhydrothermalsolutionareresponsiblefortheformationofCu-Znsulfideandbarite-amorphousSiO2mineralsthatarecharacterizedbyenrichedLREEandpositivelystrongEuanomalies.