简介:TheYinyanporphyrytindepositisablinddepositassociatedwithasmallgraniteporphyrystock.ThepetrologyandgeochemistryoftheYinyangraniteporphyrysuggestthatitisgeneticallyofthetransfor-mationtype,emplacedatthelatestageoffractionalcrystallizationwithinahigh-levelmagmachamber.Ore-formingfluidsarederivedpredominantlyfromthegraniticmagmaandtheyinteractwiththewallrocksintenselywhenfindingtheirwayupwardsthroughthegraniteporphyry.Fromthelowerpartoftheporphyryupwardsthefollowingalterationzonescanbedistinguished(a)slightlyalteredgraniteporphyry(withweakpotashfeldspathization),(b)protolithionite-quartzgreisenizationzone,(c)to-paz-quartzgreisenizationzone,(d)senicite-quartzsericitizationzone,and(e)silicificationzone(quartzcoreatthesurface).Tinmineralizationisrelatedtogreisenization,especiallytotopaz-quartzgreisenization.Rockandore-formingtemperaturesandoxygenfugacitiesareestimated,respectively.TherearesignificantdifferencesinmanyaspectsbetweentheYinyanporphyrytindepositandvolcan-ic-subvolcanicporphyrytindeposits.
简介:在这糊REE集中和Sr和从Furong矿石的Bailashui锡矿床的荧石的Nd同位素组成回答的在场的作者,南部的湖南省。结果证明在荧石的REE的全部的数量通常是低的,从有在学习区域的Qitianling花岗石的类似于那些的使球粒状陨石正常化的REE分发模式的0.705~8.785μg/g,与显著否定Eu异例由LREE丰富模式描绘了。荧石在范围以内在Sr同位素组成变化0.70830.7091,价值比在这个区域的主人碳酸盐岩石的那些是比花岗石并且高的那些低的。ɛ荧石的Nd(t)价值在−9.4和+10.3之间变化,两个都揭示那外壳--并且披风来源材料涉及形成矿石的热水的液体。在这张矿床上与以前的研究结合了,Bailashui锡矿床是速度集合并且仔细空间地在这个区域与花岗石的岩浆酌联系。热水的荧石是在热水的液体和海洋的碳酸盐摇的花岗石的magmatic之间的液体/岩石相互作用的产品。而在形成矿石的液体的Sr主要来自热水的液体和海洋的碳酸盐摇的花岗石的magmatic,在形成矿石的液体的REE和F从花岗石被导出,尽管在Sr同位素组成的变化不能被这二结束成员的简单混合物解释。证据证明形成矿石的液体具有外壳披风的混合起源,但是液体可能是,这不完全地一致,这可以被不同来源的液体的不同类的混合引起。
简介:TheDachangtin-polymetallicdistrict,Guangxi,China,isoneofthelargesttinorefieldsintheworld.Bothcassiterite-sulfideandZn-CuskarnmineralizationarehostedintheMid-UpperDevoniancarbonate-richsedi-mentsadjacenttotheunderlyingCretaceousLongxianggaigranite(91-97Ma).TheLamoZn-CudepositisatypicalskarndepositinthedistrictandoccursatthecontactzonebetweentheUpperDevonianlimestoneandthegranite.Theoremineralsmainlyconsistofsphalerite,arsenopyrite,pyrrhotite,galena,chalcopyrite,andminormolybdenite.However,theageofmineralizationandsourceofthemetalsarenotwellconstrained.Inthisstudy,weusethemolybdeniteRe-Osdatingmethodandin-situPbisotopesofsulfidesfromtheLamodepositforthefirsttimeinordertodirectlydeterminetheageofmineralizationandthetracingsourceofmetals.SixmolybdenitesamplesyieldedamoreaccurateRe-Osisochronageof90.04-1.1Ma(MSWD--0.72),whichismuchyoungerthanthereportedgarnetSm-Ndisochronageof95±11MaandquartzfluidinclusionsRb-Srisochronageof99±6Ma.ThisageisalsointerpretedastheageofZn-Cuskarnminer-alizationintheDachangdistrict.Further,inthisstudywefoundthatin-situPbisotopesofsulfidesfromtheLamodepositandfeldsparsinthedistrict'sbiotitegraniteandgraniticporphyrydikeshaveanarrowrangeandanoverlapofPbisotopiccompositions(206pb/204pb18.417-18.594,207pb/204pb=15.641-15.746,and208pb/204pb=38.791-39.073),suggestingthatthemetalsweremainlysourcedfromCretaceousgraniticmagma.