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1、2013年12月礦床地質(zhì)第32卷第6期December,2013MINERALDEf)C熔ITS32(6):1249~1261文章編號(hào):0258—7106(2013)06—1249—13河南小秦嶺楊砦峪金礦床成礦流體特征熊索菲,丁振舉,姚書(shū)振卜,熊杰2,胡新露1,何謀春~,譚滿堂(1中國(guó)地質(zhì)大學(xué)資源學(xué)院,湖北武漢430074;2廣西國(guó)土資源規(guī)劃院,廣西南寧530022;3中國(guó)地質(zhì)大學(xué)地質(zhì)過(guò)程與礦產(chǎn)資源國(guó)家重點(diǎn)實(shí)驗(yàn)室,湖北武漢430074)摘要河南省楊砦峪金礦床位于華北克拉通南緣,是小秦嶺地區(qū)大型的石英脈型金礦床。據(jù)野外觀察,成礦過(guò)程經(jīng)歷了4個(gè)階段:I黃鐵礦一石英脈階段;Ⅱ石英一黃
2、鐵礦階段;Ⅲ石英一多金屬硫化物階段;Ⅳ石英一碳酸鹽階段。包裹體巖相學(xué)、顯微測(cè)溫以及激光拉曼顯微探針研究顯示,該礦床為COg—I-I2()_Naa±C/--I4流體體系,并且發(fā)生不混溶。從第1成礦階段到Ⅳ成礦階段,流體包裹體的均一溫度范圍分別是307-407℃,270-320℃,225~27YC和166-226℃,呈現(xiàn)逐步降低的趨勢(shì);鹽度叫(NaC1)平均值分別為7.3%,7.1%,9.0%和6.4%。各階段成礦壓力為120~178MPa,85~140MPa,75~130MPa和60~122MPa,呈現(xiàn)逐漸降低的趨勢(shì)。流體不混溶作用是導(dǎo)致楊砦峪礦質(zhì)沉淀的重要原因,其誘因可能與控礦斷
3、裂由壓扭轉(zhuǎn)為張扭所導(dǎo)致的構(gòu)造減壓有關(guān)。關(guān)鍵詞地球化學(xué);流體包裹體;流體不混溶;楊砦峪金礦;小秦嶺金礦田中圖分類號(hào):P681.51文獻(xiàn)標(biāo)志碼:ACharacteristicsofore-formingfluidofYangzhaiyugolddepositinXiaoqinlinggolddistrict,HenanProvinceXIONGSuoFei,DINGZhenJu,YAOShuZhen,XIONGJie2,F(xiàn)lUXinLu,HEMouChun·andTANManTang(1FacultyofEarthResources,ChinaUniversityofGeoscien
4、ces,Wuhan430074,Hubei,China;2GuangxiLandandResourcesPlanningInstitute,Nanning530022,Guangxi,China;3StateKeyLaboratoryofGeologicalProcessandMineralResources,ChinaUniversityofGeosciences,Wuhan430074,Hubei,China)AbstractLocatedinthesouthernmarginoftheNorthChinaCraton,theYangzhaiyugolddepositinHe
5、nanProvinceisoneofnumerouslodegolddepositsinXiaoqinlingregion.Theore—formingprocesscanbedividedintofourstages,i.e.,工pyrite—quartzveinstage,1Iquartz—pyritestage,IIIquartz—polymetallicsulfidesstage,andIVquartz-carbonatestage.Researchesbasedonpetrography,fluidinclusiontestsandLaserRamanspectrosc
6、opicanalysissuggestthatore—formingfluidsaremainlycomposedofco2一HaO—NaC1±CHd.Thereisanimmiscibleprocessinthefluidsystem.Thehomogenizationtemperaturesofore—formingfluidsfromstage工tostageare307.0-406.8C,270.3~319.6C,225.4-272.1Cand166.3-226.3℃respectively,withthecorrespond—ingaveragesalinitiesbe
7、ing7.25%NaCleqv,7.14%NaCleqv,8.97%NaCleqvand6.39%NaCleqv.Thetrap—pingpressuresoffluidinclusionsareestimatedtobe120~178MPa.85~140MPa.75~130MPaand60~122mPaforeachstage.Fluidimmiscibilitymusthaveplayedanimportantroleinoregenesis.Thecauseoffluid*