四川石棉碲矿床成矿流体物理化学特性的热力学研究
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摘要
大水沟碲矿床位于石棉地区滨东韧性剪切带与西油坊韧性剪切带之间的大水沟穹窿体北倾伏端。矿区内构造活动复杂,韧性—脆性剪切带与穹窿体构造为含矿流体活动提供了有利的成矿环境,并控制了矿体的产出。矿床围岩主要是三叠纪变基性火山岩及大理岩,绿片岩和千枚岩。热液蚀变主要为碳酸岩化和硅化等。矿体呈脉状产出。主要矿石矿物为楚碲铋矿与辉碲铋矿等。
本文以野外地质研究及室内测试数据为依据,采用大地构造学及构造地球化学的理论和研究方法,研究了碲矿床形成的区域地质构造背景。采用矿床学、矿床地球化学、成因矿物学的理论和研究方法,研究了碲矿化特征、矿体特征、热液蚀变类型及其空间分布、矿石类型及其特征、矿石结构构造、矿物共生组合特点。使用冷热台均一法测试了样品的均一温度,分析了流体包裹体的成分及其同位素组成,并利用地球化学热力学原理和计算方法处理数据,获取了成矿流体的物理化学参数。
通过以上研究得出了如下结论:
(1)碲矿床产于在板块拼接地带的过渡性构造带。这种过渡性构造带有利于发育深大断裂系统,塑造出了充分的赋矿空间及成矿流体的活动场所。
(2)矿床范围内热液作用十分强烈,围岩蚀变十分发育。碲矿化与围岩蚀变关系十分密切。其中,最密切的围岩蚀变类型为白云石化、硅化,种种证据表明,碲矿床的富集与白云石化具有非常密切的关系。围岩蚀变有明显的分带性与对称性。这表明,碲矿化是在成矿热液作用时间长、作用比较充分的条件下形成的。
(3)矿物流体包裹体成分、性质与同位素地球化学研究表明,矿床的成矿流体来源于深部岩浆热液。这种成矿流体性质具有:高温,富碱,相对高氧逸度(高自由氧),高硫逸度(高自由硫)的特性。
(4)碲矿床的形成,是由于成矿流体在深部地质营力作用下进入有利的成矿环境时,热液系统的物理化学条件改变,即成矿热流体的T、P、pH、fo_2、fs_2逐渐降低及Eh值的升高,导致Te元素与配合物被解析,发生成矿作用。在成矿作用发生过程中,Te从成矿流体中析出,沉淀富集成矿。?
The Dashuigou tellurium deposit is located in northern lower end of Dashuigou dome between Bindong ductile shear zone and Xiyoufang ductile shear zone in Shimian of Sichuan province. The geology structure is very complicated here. The ductile-brittle shear zone and the dome provided advantaged spatial condition for the mineralization and controlled the occurrence of ore bodies. The host rocks for the mineralization are of Triassic metabasic volcano rock and dynamothermal metamorphic marble, greenschist and phyllite. Wall-rock alterations are extensively developed there and the main alterations are carbonatization and silicification. The main minerals are tsumoite, tetradymite, and so on.
Based on large geological investigations in the flied and a lot of analytical data gained in the laboratory, the author is studying on the fluid inclusion characteristics of the deposit. This study covers regional geology, ore deposit geology and the fluid inclusions chemistry. The regional geologic settings is studied by applying the modern thoughts and basic methods of architectonices and tectonic-geochemistry. The ore deposit, Te-mineralization, ore bodies, hydrothermal alteration, mineral paragenesis and so on are researched by applying the modern thoughts and basic methods of metallogeny, geochemistry, mineral geology. The fluid inclusions chemistry is based on temperature test by homogenization method on the hot and cold stages for upright Microscopes and on calculating by the geochemical thermodynamics method. As a result, the author calculated the physical and chemical parameters of the ore-forming fluids.
As a result, the following conclusions are derived:
1. the tellurium deposit is formed in the site where the plates splice of which is conducive deep fractures systems develop, grant plenary spaces for ore-forming and for ore-bearing fluids activities.
2. Within the deposit, the hydrothemal activity is very strong, and the wall rocks are well developed. The mineralization of tellurium is very closely related to the wall rocks alteration. The most important alteration types are dolomitization and silicification. All evidences suggest that the enrichment of tellurium has a very close relationship to the dolomitization. Further more, the alterations of wall rocks have obvious features of zonation and symmetry. These evidences indicate that the tellurium mineralization is formed under the conditions of long-term hydrothermal activity and full reactions.
3. The researches of the compositions and features of fluid inclusions and the studies of isotopic geochemistry have shown that the ore-bearing fluids are sources from the deep magmatic hydrothermal fluids with characteristics of high temperature, full of alkali, high ?o2 (free oxygen) and high ?s2 (free sulfur).
4. The formation process of the tellurium deposit is the result of the changes of the physical and chemical conditions of hydrothermal systems when the ore-bearing fluids are forced into the forming favorable environment by the deep geological forces. the values of T, P, pH, ?o2 and ?s2 gradually decreased and the the Eh value increased leading the Te and its complexes to be resolved, so that mineraliztion is occured. During the process, Te is enriched by precipitating from the ore-bearing fluids, and formed the deposit.
本文以野外地质研究及室内测试数据为依据,采用大地构造学及构造地球化学的理论和研究方法,研究了碲矿床形成的区域地质构造背景。采用矿床学、矿床地球化学、成因矿物学的理论和研究方法,研究了碲矿化特征、矿体特征、热液蚀变类型及其空间分布、矿石类型及其特征、矿石结构构造、矿物共生组合特点。使用冷热台均一法测试了样品的均一温度,分析了流体包裹体的成分及其同位素组成,并利用地球化学热力学原理和计算方法处理数据,获取了成矿流体的物理化学参数。
通过以上研究得出了如下结论:
(1)碲矿床产于在板块拼接地带的过渡性构造带。这种过渡性构造带有利于发育深大断裂系统,塑造出了充分的赋矿空间及成矿流体的活动场所。
(2)矿床范围内热液作用十分强烈,围岩蚀变十分发育。碲矿化与围岩蚀变关系十分密切。其中,最密切的围岩蚀变类型为白云石化、硅化,种种证据表明,碲矿床的富集与白云石化具有非常密切的关系。围岩蚀变有明显的分带性与对称性。这表明,碲矿化是在成矿热液作用时间长、作用比较充分的条件下形成的。
(3)矿物流体包裹体成分、性质与同位素地球化学研究表明,矿床的成矿流体来源于深部岩浆热液。这种成矿流体性质具有:高温,富碱,相对高氧逸度(高自由氧),高硫逸度(高自由硫)的特性。
(4)碲矿床的形成,是由于成矿流体在深部地质营力作用下进入有利的成矿环境时,热液系统的物理化学条件改变,即成矿热流体的T、P、pH、fo_2、fs_2逐渐降低及Eh值的升高,导致Te元素与配合物被解析,发生成矿作用。在成矿作用发生过程中,Te从成矿流体中析出,沉淀富集成矿。?
The Dashuigou tellurium deposit is located in northern lower end of Dashuigou dome between Bindong ductile shear zone and Xiyoufang ductile shear zone in Shimian of Sichuan province. The geology structure is very complicated here. The ductile-brittle shear zone and the dome provided advantaged spatial condition for the mineralization and controlled the occurrence of ore bodies. The host rocks for the mineralization are of Triassic metabasic volcano rock and dynamothermal metamorphic marble, greenschist and phyllite. Wall-rock alterations are extensively developed there and the main alterations are carbonatization and silicification. The main minerals are tsumoite, tetradymite, and so on.
Based on large geological investigations in the flied and a lot of analytical data gained in the laboratory, the author is studying on the fluid inclusion characteristics of the deposit. This study covers regional geology, ore deposit geology and the fluid inclusions chemistry. The regional geologic settings is studied by applying the modern thoughts and basic methods of architectonices and tectonic-geochemistry. The ore deposit, Te-mineralization, ore bodies, hydrothermal alteration, mineral paragenesis and so on are researched by applying the modern thoughts and basic methods of metallogeny, geochemistry, mineral geology. The fluid inclusions chemistry is based on temperature test by homogenization method on the hot and cold stages for upright Microscopes and on calculating by the geochemical thermodynamics method. As a result, the author calculated the physical and chemical parameters of the ore-forming fluids.
As a result, the following conclusions are derived:
1. the tellurium deposit is formed in the site where the plates splice of which is conducive deep fractures systems develop, grant plenary spaces for ore-forming and for ore-bearing fluids activities.
2. Within the deposit, the hydrothemal activity is very strong, and the wall rocks are well developed. The mineralization of tellurium is very closely related to the wall rocks alteration. The most important alteration types are dolomitization and silicification. All evidences suggest that the enrichment of tellurium has a very close relationship to the dolomitization. Further more, the alterations of wall rocks have obvious features of zonation and symmetry. These evidences indicate that the tellurium mineralization is formed under the conditions of long-term hydrothermal activity and full reactions.
3. The researches of the compositions and features of fluid inclusions and the studies of isotopic geochemistry have shown that the ore-bearing fluids are sources from the deep magmatic hydrothermal fluids with characteristics of high temperature, full of alkali, high ?o2 (free oxygen) and high ?s2 (free sulfur).
4. The formation process of the tellurium deposit is the result of the changes of the physical and chemical conditions of hydrothermal systems when the ore-bearing fluids are forced into the forming favorable environment by the deep geological forces. the values of T, P, pH, ?o2 and ?s2 gradually decreased and the the Eh value increased leading the Te and its complexes to be resolved, so that mineraliztion is occured. During the process, Te is enriched by precipitating from the ore-bearing fluids, and formed the deposit.
引文
[1]百度百科,http://baike.baidu.com/view/30133.htm
[2]Ayres, Robert U., Ayres, Leslie. A handbook of industrial ecology.Edward Elgar Publishing. 2002:p.396.
[3]曹志敏,骆耀南.四川石棉县碲(铋)矿床特征与物质组分.第五届全国矿床会议文集,北京:地质出版社, 1993, 476～478.
[4]银剑钊,周剑雄,杨百川,等.世界首例独立碲矿床:中国四川石棉县大水沟碲矿的矿床地质特征[J] .地学前缘, 1994,4: 241～243.
[5]毛景文,陈毓川,魏家秀.四川省石棉县大水沟碲矿床成矿物质来源的一些证据[J] .贵金属地质,1995,4(4) :294～301.
[6]银剑钊,陈毓川,周剑雄,杨百川.世界首例独立碲矿床赋矿围岩的原岩恢复[J].矿物岩石地球化学通报. 1995,2.
[7]骆耀南,曹志敏.大水沟独立碲矿床-世界首例碲化物脉型矿床地质地球化学.西南交通大学出版社. 1996.
[8]王汝成,陈小明,徐士进,陆建军,沈渭洲,骆耀南,胡宝山.大水沟碲矿床中碲矿物的复杂出溶现象[J].科学通报,1996.10.
[9]王汝成,徐士进,陈小明.四川大水沟独立啼矿床中的楚碲秘矿.矿物学报,1997 ,17(3):280～284
[10]李保华,曹志敏,金景福,温春齐.大水沟碲矿床成矿物理化学条件研究.地质科学,1999,34(4):463～472
[11]曹志敏.大水沟碲矿床成矿条件与碲的矿机理研究[D].成都理工大学博士论文,1995.
[12]郑大中,郑若锋.大水沟独立碲矿床形成机理研究.地质找矿论丛,2000,15(3):230～237.
[13]温春齐,曹志敏,李保华.四川大水沟碲矿床成矿物质来源研究[J].成都理工学院学报,2002,29( 5): 526～532.
[14]曹志敏、李保华、陈翠华、宋谢炎.大水沟碲矿床成矿物理化学条件研究.分散元素地球化学及成矿机制,地质出版社,2004.
[15]罗改,何明友,谭晓莲,马东.四川石棉碲矿床碲迁移形式和富集机理探讨.广东微量元素科学,2008,15(7):63～67
[16]许志琴,候立玮.松潘—甘孜造山带构造研究新进展[J].中国地质,1991,12: 14～16.
[17]郭建强,游再平,王大可.松潘一甘孜造山带东缘大水沟地区变质变形作用[J].中国区域地质,1999,312～319.
[18]张程远,四川石棉碲矿床元素地球化学研究[M].成都理工大学硕士论文,2010.
[19]石棉幅区域地质测量报告.四川省地质矿产局区域地质调查队,1974.
[20]四川省区域地质志[M].四川省地质矿产局.地质出版社,1991:220～221.
[21]骆耀南,傅德明,周绍东.四川石棉大水沟碲矿床地质与成因[J].四川地质学报,1994, 14( 2) : 100～110.
[22]喻安光.四川石棉—冕宁地区之伸展构造.中国区域地质,2000,Vol.19,20～25.
[23]骆耀南,曹志敏,温春齐.大水沟独立碲矿床.西南交通大学出版社,1996:30～45.
[24]李保华,曹志敏,温春齐.大水沟磅矿床矿脉特征及包裹体类型[J].矿物岩石地球化学通报,2000,19(4):346～349.
[25]卢焕章,范宏瑞,倪培.流体包裹体.科学出版社,2004.
[26]刘英俊,曹励明.元素地球化学[M].科学出版社,1984.
[27]Taylor, H.P. Jr., 1974, The Application of oxygen and hydrogen isotope studies to problems of hydrothermal alteration and ore deposition, Econ. Genl., 69:843～883.
[28]魏菊英、王关.同位素地球化学.地质出版社,1988.
[29]何明友.论云南老王寨金矿田形成的地球化学机理〔D〕.博士后科学研究论文.1996
[30]饶纪龙.地球化学中的热力学[M].科学出版社,1979.
[31]邵洁涟.金矿找矿矿物学[M].中国地质大学出版社,1988.
[32]林传仙等.矿物及有关化合物热力学数据手册.科学出版社,1985.
[33]西油房幅区域地质测量报告.四川省地质矿产局区域地质调查队,1996.
[2]Ayres, Robert U., Ayres, Leslie. A handbook of industrial ecology.Edward Elgar Publishing. 2002:p.396.
[3]曹志敏,骆耀南.四川石棉县碲(铋)矿床特征与物质组分.第五届全国矿床会议文集,北京:地质出版社, 1993, 476～478.
[4]银剑钊,周剑雄,杨百川,等.世界首例独立碲矿床:中国四川石棉县大水沟碲矿的矿床地质特征[J] .地学前缘, 1994,4: 241～243.
[5]毛景文,陈毓川,魏家秀.四川省石棉县大水沟碲矿床成矿物质来源的一些证据[J] .贵金属地质,1995,4(4) :294～301.
[6]银剑钊,陈毓川,周剑雄,杨百川.世界首例独立碲矿床赋矿围岩的原岩恢复[J].矿物岩石地球化学通报. 1995,2.
[7]骆耀南,曹志敏.大水沟独立碲矿床-世界首例碲化物脉型矿床地质地球化学.西南交通大学出版社. 1996.
[8]王汝成,陈小明,徐士进,陆建军,沈渭洲,骆耀南,胡宝山.大水沟碲矿床中碲矿物的复杂出溶现象[J].科学通报,1996.10.
[9]王汝成,徐士进,陈小明.四川大水沟独立啼矿床中的楚碲秘矿.矿物学报,1997 ,17(3):280～284
[10]李保华,曹志敏,金景福,温春齐.大水沟碲矿床成矿物理化学条件研究.地质科学,1999,34(4):463～472
[11]曹志敏.大水沟碲矿床成矿条件与碲的矿机理研究[D].成都理工大学博士论文,1995.
[12]郑大中,郑若锋.大水沟独立碲矿床形成机理研究.地质找矿论丛,2000,15(3):230～237.
[13]温春齐,曹志敏,李保华.四川大水沟碲矿床成矿物质来源研究[J].成都理工学院学报,2002,29( 5): 526～532.
[14]曹志敏、李保华、陈翠华、宋谢炎.大水沟碲矿床成矿物理化学条件研究.分散元素地球化学及成矿机制,地质出版社,2004.
[15]罗改,何明友,谭晓莲,马东.四川石棉碲矿床碲迁移形式和富集机理探讨.广东微量元素科学,2008,15(7):63～67
[16]许志琴,候立玮.松潘—甘孜造山带构造研究新进展[J].中国地质,1991,12: 14～16.
[17]郭建强,游再平,王大可.松潘一甘孜造山带东缘大水沟地区变质变形作用[J].中国区域地质,1999,312～319.
[18]张程远,四川石棉碲矿床元素地球化学研究[M].成都理工大学硕士论文,2010.
[19]石棉幅区域地质测量报告.四川省地质矿产局区域地质调查队,1974.
[20]四川省区域地质志[M].四川省地质矿产局.地质出版社,1991:220～221.
[21]骆耀南,傅德明,周绍东.四川石棉大水沟碲矿床地质与成因[J].四川地质学报,1994, 14( 2) : 100～110.
[22]喻安光.四川石棉—冕宁地区之伸展构造.中国区域地质,2000,Vol.19,20～25.
[23]骆耀南,曹志敏,温春齐.大水沟独立碲矿床.西南交通大学出版社,1996:30～45.
[24]李保华,曹志敏,温春齐.大水沟磅矿床矿脉特征及包裹体类型[J].矿物岩石地球化学通报,2000,19(4):346～349.
[25]卢焕章,范宏瑞,倪培.流体包裹体.科学出版社,2004.
[26]刘英俊,曹励明.元素地球化学[M].科学出版社,1984.
[27]Taylor, H.P. Jr., 1974, The Application of oxygen and hydrogen isotope studies to problems of hydrothermal alteration and ore deposition, Econ. Genl., 69:843～883.
[28]魏菊英、王关.同位素地球化学.地质出版社,1988.
[29]何明友.论云南老王寨金矿田形成的地球化学机理〔D〕.博士后科学研究论文.1996
[30]饶纪龙.地球化学中的热力学[M].科学出版社,1979.
[31]邵洁涟.金矿找矿矿物学[M].中国地质大学出版社,1988.
[32]林传仙等.矿物及有关化合物热力学数据手册.科学出版社,1985.
[33]西油房幅区域地质测量报告.四川省地质矿产局区域地质调查队,1996.