湘西西安钨矿床白钨矿的地球化学特征及对矿床成因的指示
Geochemistry of scheelite in the Xi’an tungsten deposit, western Hunan, and its implications for its ore genesis
查看参考文献113篇
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文摘
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赋存于变质岩中的层控(层状)型钨矿床的成因在国际矿床学界一直存在争议,白钨矿的元素和同位素地球化学研究是解决其成因争议的有效手段。位于雪峰弧形构造带中的西安钨矿床是该类矿床的典型代表,其矿床成因也存在着很大争议。本文利用EMPA、ICP-MS、ID-MS等多种分析手段,对该矿白钨矿的主量元素、微量元素、及Sm-Nd和Sr同位素进行了研究。研究表明,该区白钨矿中CaO含量小于其理论值,这可能与热液流体中的REE、Sr、Pb、Ba等元素与白钨矿中的Ca发生类质同象置换有关;该区白钨矿微量元素组成具有富Sr、而亏损Mo、Bi、 Sn、Nb、Ta等特征,类似于西澳绿岩带型金矿、云南大坪和湘西沃溪等造山型金矿床中的白钨矿,其Mo含量和Sr/Mo值均显示其具变质热液成因特征,而与岩浆热液无关;该区白钨矿的稀土元素配分模式相当一致,均表现为LREE亏损、HREE相对富集、MREE最为富集的特征,其分配行为主要表现为REE3+与Na~+以电价补偿形式替代Ca~(2+)而选择性进入白钨矿晶格中;该区白钨矿n(~(87)Sr)/n(~(86)Sr)测定值为0.75412~0.78231,表明形成该区白钨矿的成矿流体并非来自海水或岩浆热液,其矿床成因也并非前人所认为的“海底热泉(卤水)沉积成因”、“海底同生喷流沉积成因”或“岩浆期后热液成因”。在LREE—MREE—HREE三角判别图解中,西安矿区白钨矿样品点均落入加拿大、澳大利亚和湘西造山型金矿区域,明显不同于与岩浆活动有关的钨矿床,该矿是属于造山型钨矿;在Sr—Nd同位素组成图解中,该区白钨矿与湘西一带出露的新元古代地层明显分布在不同区域,但部分样品点与华南最老地层—太古宇崆岭群重叠,暗示该矿成矿物质可能来自深部的太古宇崆岭群,而非来自赋矿的新元古界变质岩。 |
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其他语种文摘
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The ore genesis of stratabound (stratiform) tungsten deposits hosted in metamorphic rocks has remained controversial during the past several decades. Elemental and isotopic geochemistry of scheelite is an effective tool to solve this above dispute. The Xi’an tungsten deposit in Western Hunan, located at the Xuefeng arc structural zone, is a typical deposit, its ore origin is still disputed. Using different analytical methods including EMPA, ICP-MS and ID-MS, the geochemical compositions of the scheelite samples collected from the Xi’ an tungsten deposit have been determined in order to reveal their elemental and isotopic signatures. It is revealed that the contents of CaO in scheelite are less than the corresponding theoretical value, which can be ascribed to the substitution of REE, Sr, Pb, Ba and other trace elements into Ca site in the scheelite lattice; The studied scheelite is relatively rich in Sr and depleted in Mo, Bi, Sn, Nb and Ta, which is similar to those scheelite in the gold/tungsten deposits in Western Australia, Daping and Woxi in China. The Mo concentrations and Sr/Mo ratios for scheelite samples in this study reveal that, scheelite in the Xi’an deposit is of metamorphic—hydrothermal origin rather than of magmatic—hydrothermal origin. All scheelite samples are characterized by the LREE-depleted, MREEand HREE-enriched pattern, the REE substitution into Ca~(2+) site of the scheelites was implemented by the charge compensation mechanism (REE3+ +Na~+ = 2Ca~(2+)); The n(87 Sr)/n(86 Sr) values of the studied scheelite samples vary in the range of 0.75412 ~ 0.78231, significantly higher than the Sr isotopic composition of Phanerozoic seawater or of granitic rocks in central Hunan, which implies that the mineralizing fluid isn’t derived from magmatic water or paleo-seawater, and that the deposit shouldn’ t be classified into the “ magmatic hydrothermal origin” or “seafloor hot spring (brine) sedimentary origin or seafloor syngenetic sedex origin” as previously expected. Combined with the LREE—MREE—HREE diagram, it can be concluded that the Xi’ an tungsten deposit is a typical orogenic deposit. It is revealed that the studied scheelite and the Neoproterozoic strata outcropped in western Hunan are obviously distributed in different areas in the diagram of Sr—Nd isotopic composition, but a few of scheelite samples overlap with the Archean Kongling Group in South China, therefore, the tungsten mineralization in this area is probably associated with the underlying Archean strata rather than the hosted Neoproterozoic strata. |
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来源
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地质论评
,2022,68(5):1772-1788 【核心库】
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DOI
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10.16509/j.georeview.2022.09.065
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关键词
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白钨矿
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微量元素
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Sr—Nd同位素
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矿床成因
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西安钨矿床
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地址
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1.
湖南有色金属职业技术学院资源环境系, 湖南, 株洲, 412000
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湖南城市学院土木工程学院, 湖南, 益阳, 413000
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中国科学院地球化学研究所, 矿床地球化学国家重点实验室, 贵阳, 550081
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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0371-5736 |
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学科
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地质学 |
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基金
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国家自然科学基金资助项目
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湖南省自然科学基金
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文献收藏号
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CSCD:7292265
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参考文献 共
113
共6页
|
|
1.
包正相. 湘西层控白钨矿床地质特征及其成矿作用.
矿床地质,1987,6(4):34-38
|
被引
1
次
|
|
|
|
|
2.
包正相. 湘西层控白钨矿矿床的产状特征、成矿作用与找矿标志.
地质与勘探,1988,8(3):15-20
|
被引
1
次
|
|
|
|
|
3.
鲍正襄. 湘西前寒武纪白钨矿床成矿特征及控矿因素.
江西地质,2001,15(1):39-44
|
被引
4
次
|
|
|
|
|
4.
顾雪祥. 湖南沃溪钨—锑—金矿床的矿石组构学特征及其成因意义.
矿床地质,2003,22(2):107-120
|
被引
20
次
|
|
|
|
|
5.
顾雪祥. 湖南沃溪金-锑-钨矿床成因的稀土元素地球化学证据.
地球化学,2005,34(5):428-442
|
被引
19
次
|
|
|
|
|
6.
何谷光. 湘西西安白钨矿床的地球化学特征.
地质地球化学,1985,13(8):65-66
|
被引
1
次
|
|
|
|
|
7.
何江. 江南古陆边缘渣滓溪锑矿带成矿作用地球化学研究.
矿床地质,1996,15(1):41-52
|
被引
13
次
|
|
|
|
|
8.
李键炎. 沃溪金锑钨矿床的地质特征.
地质与勘探,1989,25(12):1-7
|
被引
5
次
|
|
|
|
|
9.
黎盛斯. 湘西白钨矿之发现.
地质论评,1949(Z1):71-72
|
被引
4
次
|
|
|
|
|
10.
梁博益. 湘西沃溪金锑钨矿床石英的标型特征研究.
湖南地质,1986,5(2):17-25
|
被引
2
次
|
|
|
|
|
11.
梁博益. 湘西沃溪金锑钨矿床成因矿物学研究.
地质与勘探,1988,24(8):25-30
|
被引
4
次
|
|
|
|
|
12.
梁金城. 湘西沃溪金矿床层状石英脉的显微构造与组构探讨.
桂林冶金地质学院学报,1981,1(3):41-52
|
被引
9
次
|
|
|
|
|
13.
刘琰. 四川雪宝顶白钨矿稀土地球化学与Sm-Nd同位素定年.
科学通报,2007,52(16):1923-1929
|
被引
22
次
|
|
|
|
|
14.
刘英俊.
钨的地球化学,1987
|
被引
18
次
|
|
|
|
|
15.
罗献林. 论湘西沃溪金锑钨矿床的成因.
地质与勘探,1984,4(7):3-12
|
被引
1
次
|
|
|
|
|
16.
罗献林.
湖南省沃溪式层控金矿地质,1996
|
被引
1
次
|
|
|
|
|
17.
毛景文. 江南古陆某些金矿床成因讨论.
地球化学,1997,26(5):71-81
|
被引
39
次
|
|
|
|
|
18.
毛景文.
湖南万古地区金矿地质与成因,1997
|
被引
12
次
|
|
|
|
|
19.
孟宪民.
矿床分类与成矿作用,1963
|
被引
1
次
|
|
|
|
|
20.
彭渤. 湘西沃溪W—Sb—Au矿床白钨矿Nd—Sr—Pb同位素对成矿流体的示踪.
地质学报,2006,80(4):561-570
|
被引
28
次
|
|
|
|
|
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