安徽冬瓜山矽卡岩铜矿石榴石成分特征及其成因探讨
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摘要
对安徽铜陵冬瓜山铜矿石榴石的地球化学特征进行了研究,并进行了成因探讨。野外调查及镜下观察发现,冬瓜山铜矿石榴石分为两期形成,第Ⅰ期石榴石环带发育,颜色较深,呈褐-棕黄色;第Ⅱ期石榴石呈他形-半自形穿切Ⅰ期,颜色较浅,呈浅黄-蜡白色,具非均质性。石榴石主量、稀土元素的等离子光谱(LA-ICP-MS)分析结果显示这两期石榴石有较大差别:第Ⅰ期石榴石钙铁榴石组分含量较高,可达94.14%,稀土元素配分模式为轻稀土元素富集、Eu正异常的右倾曲线;第Ⅱ期石榴石则相对富铝,钙铝榴石组分含量达44.06%,稀土元素配分模式为重稀土元素略微富集、Eu负异常的平缓曲线。这些特征表明,第Ⅰ期石榴石为岩浆成因,形成于较氧化环境;第Ⅱ期石榴石为热液交代成因,形成于较还原环境。
Located in northern Shizishan orefield of Tongling area,Anhui Province,the Dongguashan skarn copper deposit is a typical stratabound skarn copper deposit in China.Garnet is the main mineral in the skarn system,whose content is up to 95%.According to the garnet geochemical features of the study area,this paper intends to provide evidence of its origin.Based on field survey and microscope observation,the authors have found that garnet in the Dongguashan copper deposit can be divided into two stages: stageⅠ garnet has well-developed girdle,and its color is dark brown;stageⅡgarnet cuts the first,is anhedral-subhedral in shape,and has heterogeneity,with its color being light pale yellow-wax white.The major elements and REE compositions of the two phases of garnets were analyzed by plasma spectrometry(LA-ICP-MS),and the results show remarkable differences between them: the andradite component of stageⅠgarnet is higher,which is up to 94.14%,its REE distribution is characterized by rightly-oblique curves of enriched light rare earth elements(LREE) with positive Eu anomaly,while stage Ⅱ garnet is Al-rich,its grossular component is up to 44.06% and its REE patterns display a tendency of slight heavy rare earth elements(HREE) enrichment and strong negative Eu anomaly.These features indicate that the first stage garnet is of magmatic genesis and was formed in oxidizing conditions,whereas the second stage garnet is of hydrothermal metasomatic genesis and was formed in a reductive environment.
Located in northern Shizishan orefield of Tongling area,Anhui Province,the Dongguashan skarn copper deposit is a typical stratabound skarn copper deposit in China.Garnet is the main mineral in the skarn system,whose content is up to 95%.According to the garnet geochemical features of the study area,this paper intends to provide evidence of its origin.Based on field survey and microscope observation,the authors have found that garnet in the Dongguashan copper deposit can be divided into two stages: stageⅠ garnet has well-developed girdle,and its color is dark brown;stageⅡgarnet cuts the first,is anhedral-subhedral in shape,and has heterogeneity,with its color being light pale yellow-wax white.The major elements and REE compositions of the two phases of garnets were analyzed by plasma spectrometry(LA-ICP-MS),and the results show remarkable differences between them: the andradite component of stageⅠgarnet is higher,which is up to 94.14%,its REE distribution is characterized by rightly-oblique curves of enriched light rare earth elements(LREE) with positive Eu anomaly,while stage Ⅱ garnet is Al-rich,its grossular component is up to 44.06% and its REE patterns display a tendency of slight heavy rare earth elements(HREE) enrichment and strong negative Eu anomaly.These features indicate that the first stage garnet is of magmatic genesis and was formed in oxidizing conditions,whereas the second stage garnet is of hydrothermal metasomatic genesis and was formed in a reductive environment.
引文
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Chang Yinfo,Liu Xiangpei,Wu Yanchang,et al.1991.TonglingMetallogenic Belt in Yangtze River[M].Beijing:Geological Pub-lishing House,263~269,309~318(in Chinese).
Chen Jun,Hall C and Stanley C J.1994.REE distribution pattern andthe implications of rock-forming minerals from Shizhuyuan skarntype W,Sn,Mo and Bi deposit,South China[J].Geochimica,23:84~91(in Chinese).
Feng Xiaoliang,Guan Shiping,Mou Chuanlong,et al.2001.Geologi-cal characteristics and genesis of the Jiama copper-polymetallic de-posit in Tibet[J].Geology-Geochemistry,29(4):40~48(in Chi-nese).
Gaspar M,Knaack C,Meinert L,et al.2005.REE distuibution ingrandites fromthe Crown Jewel gold skarn deposit:ALA-ICP-MSstudy[J].Geochimica et Cosmochimica Acta,69(10):788.
Gaspar M,Knaack C,Meinert L D,et al.2008.REEin skarn sys-tems:A LA-ICP-MS study of garnets fromthe Crown Jewel golddeposit[J].Geochimica et Cosmochimica Acta,72:185~205.
Gustafson WI.1974.The stability of andradite,hedenbergite,and re-lated minerals in the system Ca-Fe-Si-O-H[J].Journal of Petrolo-gy,15(3):455~496.
Han Song,Huang Zhongxiang,Jia Xiuqin,et al.1993.The geochemi-cal characteristics of rare earth elements in skarns and their garnetsfromdamoshan area,Gejiu District,Yunnan Province[J].ActaPetrologica Sinica,9(2):192~198(in Chinese).
Ling Qicong and Cheng Huilan.1998.Discussion onforming process andgeological characteristics of magmatic skarnin Tongling area,AnhuiProvince[J].Journal of Changchun University of Science and Tech-nology,28(4):366~371(in Chinese).
Ling Qicong and Liu Congqiang.2003.REE behavior during formationof strata-bound skarn and related deposit:a case study of Dong-guashan skarn deposit in Anhui province,China[J].Acta Petrologi-ca Sinica,19(1):192~200(in Chinese).
Qiu Shidong,Xie Yuling,Xu Jiuhua,et al.2007.Characteristics andevolution of ore-formingfluids associated with Yanshanian magmaticactivityin Dongguashancopper deposit,Anhui Province,China[J].Mineral Deposits,26(2):204~212(in Chinese).
Tang Yongcheng,Wu Yanchang,Chu Guozheng,et al.1998.AnhuiProvince along the Yangtze River Copper-Gold Polymetallic DepositGeology[M].Beijing:Geological Publishing House,25~143,163~168,239~245(in Chinese).
Wang Qingfei,Deng Jun,Wan Li,et al.2008.Multifractal analysis ofelement distributionin skarn-type depositsinthe Shizishan orefield,Tongling area,Anhui Province,China[J].Acta Geologica Sinica,82(4):896~905.
Xiao Chengdong and Liu Xuewu.2002.REEgeochemistry and origin ofskarn garnets fromeastern Inner Mongolia[J].Geology in China,29(3):311~316(in Chinese).
Xu Xiaochun,Zhao Lili,Xie Qiaoqin,et al.2009.Rare earth elementsof ores in gold deposits and copper deposits of Shizishan ore-field,Tongling region,Anhui Province[J].Geological Journal of ChinaUniversities,15(1):35~47(in Chinese).
Zhao Bin,Li Tongjin and Li Zhaopin.1983.Experimental study ofphysico-chemical conditions of the formation of skarns[J].Geochimica,3:256~367(in Chinese).
Zhao Bin,Li Yuansheng and Zhao Jinsong.1995.The evidencefromin-clusions for magma-genetic skarn[J].Geochimica,24(2):198~200(in Chinese).
Zhao Bin,Zhao Jinsong and Liu Haichen.1999.REEgeochemical stud-ies of whole roek and rock-forming minerals in skarns from Cu(Au),Cu-Fe(Au)and Fe ore deposits distributed along middle-low-er reaches of Yangtze river,China[J].Geochimica,28(2):113~125(in Chinese).
Zhao Jinsong,Qiu Xuelin,Zhao Bin,et al.2007.REEgeochemistry ofmineralized skarns from Daye to Wushan Region,China[J].Geochimica,36(4):400~412(in Chinese).
常印佛,刘湘培,吴言昌,等.1991.长江中下游铜陵成矿带[M].北京:地质出版社,263~269,309~318.
陈骏,Halls C,Stanley CJ.1994.柿竹园矽卡岩型钨锡钼铋矿床主要造岩矿物中REE的分布特征及成岩意义[J].地球化学,23(增刊):84~92.
冯孝良,管仕平,牟传龙,等.2001.西藏甲马铜多金属矿床的岩浆热液交代成因:地质与地球化学证据[J].地质地球化学,29(4):40~48.
韩松,黄忠祥,贾秀勤,等.1993.云南个旧打磨山钙质矽卡岩及石榴石的稀土元素地球化学特征[J].岩石学报,9(2):192~198.
凌其聪,程惠兰.1998.岩浆矽卡岩的地质特征及其形成机理讨论--以铜陵地区为例[J].长春科技大学学报,28(4):366~371.
凌其聪,刘丛强.2003.层控矽卡岩及有关矿床形成过程的稀土元素行为--以安徽冬瓜山矿床为例[J].岩石学报,19(1):192~200.
邱士东,谢玉玲,徐久华,等.2007.安徽铜陵冬瓜山铜矿床成矿流体特征及演化[J].矿床地质,26(2):204~212.
唐永成,吴言昌,储国正,等.1998.安徽沿江地区铜金多金属矿床地质[M].北京:地质出版社,125~143,163~168,239~245.
肖成东,刘学武.2002.东蒙地区矽卡岩石榴石稀土元素地球化学及其成因[J].中国地质,29(3):311~316.
徐晓春,赵丽丽,谢巧勤.2009.铜陵狮子山矿田金矿床和铜矿床矿石稀土元素地球化学[J].高校地质学报,15(1):35~47.
赵斌,李统锦,李昭平.1983.矽卡岩形成的物理化学条件实验研究[J].地球化学,(3):256~268.
赵斌,李院生,赵劲松.1995.岩浆成因矽卡岩的包裹体证据[J].地球化学,24(2):198~200.
赵斌,赵劲松,刘海臣.1999.长江中下游地区Cu(Au)/Cu-Fe(Au)和Fe矿床中钙质矽卡岩的稀土元素地球化学[J].地球化学,28(2):113~125.
赵劲松,邱学林,赵斌,等.2007.大冶-武山矿化矽卡岩的稀土元素地球化学研究[J].地球化学,36(4):400~412.
Chang Yinfo,Liu Xiangpei,Wu Yanchang,et al.1991.TonglingMetallogenic Belt in Yangtze River[M].Beijing:Geological Pub-lishing House,263~269,309~318(in Chinese).
Chen Jun,Hall C and Stanley C J.1994.REE distribution pattern andthe implications of rock-forming minerals from Shizhuyuan skarntype W,Sn,Mo and Bi deposit,South China[J].Geochimica,23:84~91(in Chinese).
Feng Xiaoliang,Guan Shiping,Mou Chuanlong,et al.2001.Geologi-cal characteristics and genesis of the Jiama copper-polymetallic de-posit in Tibet[J].Geology-Geochemistry,29(4):40~48(in Chi-nese).
Gaspar M,Knaack C,Meinert L,et al.2005.REE distuibution ingrandites fromthe Crown Jewel gold skarn deposit:ALA-ICP-MSstudy[J].Geochimica et Cosmochimica Acta,69(10):788.
Gaspar M,Knaack C,Meinert L D,et al.2008.REEin skarn sys-tems:A LA-ICP-MS study of garnets fromthe Crown Jewel golddeposit[J].Geochimica et Cosmochimica Acta,72:185~205.
Gustafson WI.1974.The stability of andradite,hedenbergite,and re-lated minerals in the system Ca-Fe-Si-O-H[J].Journal of Petrolo-gy,15(3):455~496.
Han Song,Huang Zhongxiang,Jia Xiuqin,et al.1993.The geochemi-cal characteristics of rare earth elements in skarns and their garnetsfromdamoshan area,Gejiu District,Yunnan Province[J].ActaPetrologica Sinica,9(2):192~198(in Chinese).
Ling Qicong and Cheng Huilan.1998.Discussion onforming process andgeological characteristics of magmatic skarnin Tongling area,AnhuiProvince[J].Journal of Changchun University of Science and Tech-nology,28(4):366~371(in Chinese).
Ling Qicong and Liu Congqiang.2003.REE behavior during formationof strata-bound skarn and related deposit:a case study of Dong-guashan skarn deposit in Anhui province,China[J].Acta Petrologi-ca Sinica,19(1):192~200(in Chinese).
Qiu Shidong,Xie Yuling,Xu Jiuhua,et al.2007.Characteristics andevolution of ore-formingfluids associated with Yanshanian magmaticactivityin Dongguashancopper deposit,Anhui Province,China[J].Mineral Deposits,26(2):204~212(in Chinese).
Tang Yongcheng,Wu Yanchang,Chu Guozheng,et al.1998.AnhuiProvince along the Yangtze River Copper-Gold Polymetallic DepositGeology[M].Beijing:Geological Publishing House,25~143,163~168,239~245(in Chinese).
Wang Qingfei,Deng Jun,Wan Li,et al.2008.Multifractal analysis ofelement distributionin skarn-type depositsinthe Shizishan orefield,Tongling area,Anhui Province,China[J].Acta Geologica Sinica,82(4):896~905.
Xiao Chengdong and Liu Xuewu.2002.REEgeochemistry and origin ofskarn garnets fromeastern Inner Mongolia[J].Geology in China,29(3):311~316(in Chinese).
Xu Xiaochun,Zhao Lili,Xie Qiaoqin,et al.2009.Rare earth elementsof ores in gold deposits and copper deposits of Shizishan ore-field,Tongling region,Anhui Province[J].Geological Journal of ChinaUniversities,15(1):35~47(in Chinese).
Zhao Bin,Li Tongjin and Li Zhaopin.1983.Experimental study ofphysico-chemical conditions of the formation of skarns[J].Geochimica,3:256~367(in Chinese).
Zhao Bin,Li Yuansheng and Zhao Jinsong.1995.The evidencefromin-clusions for magma-genetic skarn[J].Geochimica,24(2):198~200(in Chinese).
Zhao Bin,Zhao Jinsong and Liu Haichen.1999.REEgeochemical stud-ies of whole roek and rock-forming minerals in skarns from Cu(Au),Cu-Fe(Au)and Fe ore deposits distributed along middle-low-er reaches of Yangtze river,China[J].Geochimica,28(2):113~125(in Chinese).
Zhao Jinsong,Qiu Xuelin,Zhao Bin,et al.2007.REEgeochemistry ofmineralized skarns from Daye to Wushan Region,China[J].Geochimica,36(4):400~412(in Chinese).
常印佛,刘湘培,吴言昌,等.1991.长江中下游铜陵成矿带[M].北京:地质出版社,263~269,309~318.
陈骏,Halls C,Stanley CJ.1994.柿竹园矽卡岩型钨锡钼铋矿床主要造岩矿物中REE的分布特征及成岩意义[J].地球化学,23(增刊):84~92.
冯孝良,管仕平,牟传龙,等.2001.西藏甲马铜多金属矿床的岩浆热液交代成因:地质与地球化学证据[J].地质地球化学,29(4):40~48.
韩松,黄忠祥,贾秀勤,等.1993.云南个旧打磨山钙质矽卡岩及石榴石的稀土元素地球化学特征[J].岩石学报,9(2):192~198.
凌其聪,程惠兰.1998.岩浆矽卡岩的地质特征及其形成机理讨论--以铜陵地区为例[J].长春科技大学学报,28(4):366~371.
凌其聪,刘丛强.2003.层控矽卡岩及有关矿床形成过程的稀土元素行为--以安徽冬瓜山矿床为例[J].岩石学报,19(1):192~200.
邱士东,谢玉玲,徐久华,等.2007.安徽铜陵冬瓜山铜矿床成矿流体特征及演化[J].矿床地质,26(2):204~212.
唐永成,吴言昌,储国正,等.1998.安徽沿江地区铜金多金属矿床地质[M].北京:地质出版社,125~143,163~168,239~245.
肖成东,刘学武.2002.东蒙地区矽卡岩石榴石稀土元素地球化学及其成因[J].中国地质,29(3):311~316.
徐晓春,赵丽丽,谢巧勤.2009.铜陵狮子山矿田金矿床和铜矿床矿石稀土元素地球化学[J].高校地质学报,15(1):35~47.
赵斌,李统锦,李昭平.1983.矽卡岩形成的物理化学条件实验研究[J].地球化学,(3):256~268.
赵斌,李院生,赵劲松.1995.岩浆成因矽卡岩的包裹体证据[J].地球化学,24(2):198~200.
赵斌,赵劲松,刘海臣.1999.长江中下游地区Cu(Au)/Cu-Fe(Au)和Fe矿床中钙质矽卡岩的稀土元素地球化学[J].地球化学,28(2):113~125.
赵劲松,邱学林,赵斌,等.2007.大冶-武山矿化矽卡岩的稀土元素地球化学研究[J].地球化学,36(4):400~412.
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