安徽省繁昌县桃冲地区矿田构造研究
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摘要
桃冲矿田位于长江中下游铜-铁-金多金属成矿带中的铜陵-繁昌矿集区东北部，构造控矿作用明显。本文对矿田内的褶皱、断裂、节理和劈理进行了野外调研和实地测量，并通过变形特征观察和构造配套分析，确定了桃冲地区多期次构造活动的主应力方向。在此基础上，作者分析了构造应力场演变及其控矿意义，提出了桃冲矿田的成矿模型并据以预测了矿田内铁矿富集的有利部位。
通过上述研究，得到以下主要认识：
1、野外调研发现，桃冲地区铁矿床受构造控制作用明显，矿体整体上呈“镰刀形”；矿石主要由镜铁矿、磁铁矿及矽卡岩矿物组成，围岩蚀变主要为矽卡岩化和大理岩化。
2、通过受力分析及岩组图的观察统计，可以确定出桃冲地区主要受到过北西向、东西向及北东向构造应力，且构造应力具有多期次的特征。其中，北东向的构造应力与成矿的关系最为密切。
3、根据构造变形叠加关系将繁昌桃冲地区构造应力演化可分为3期8个阶段：成矿前期，包含前印支期（D1-2）、印支期（D3）、燕山早期（D4）；成矿期，涉及燕山晚期（D5-6）；成矿期后，包含燕山晚期（D7）和喜马拉雅期（D8）。
4、结合区域地质矿产资料，综合分析表明，桃冲地区导岩导矿构造及容矿构造较为简单，主要的导矿构造为北东向的层间断裂，主要的容矿构造为北东向的层间断裂及次级褶皱的转折端部位。
5、在以上资料的基础上，建立了以下构造成矿模型：前印支期区内主要形成基底断裂；印支期在北西向应力作用下区内发生褶皱变形并伴随层间滑脱；在燕山早期构造应力的诱发下，前印支期基底断裂和印支期层间断裂发生活化，沟通深部岩浆房，导致岩浆上涌；至燕山晚期，层间断裂进一步张裂，岩浆晚期分异出的成矿物质上升充填在层间断裂及次级褶皱转折端形成矿体。
Taochong orefield is located in the northeast of the Tongling-Fanchang oreconcentration area, which is an important segment of the Lower and Middle Yangtzeiron-copper-gold metallogenic belt, and evidently controlled by structures. Fieldinvestigation and measurement have been carried out on the folds, faults, joints andcleavages in the orefield, with determination on the principal stress directions of themultiphase structural activities through deformation characteristics observation andstructural set analysis. On the basis of the study, an analysis has been completed onthe evolution of tectonic stress field in the orefield and its significance in controllingof ore deposits, a model proposed for mineralization in the Taochong orefield, and aprediction done on the favorable locations for iron deposits concentration in theorefield based on the model.
The following are major achievements obtained in this thesis:
1. Taochong orefield is evidently controlled by structures, and the ore bodyoccurs as falciform. Ores consist of specularite, magnetite and skarn-minerals andwall alteration includes skarnization and marbleization.
2. Through the stress analysis and the petrotectonics observation, the principalstress directions in Taochong orefield are determined as northwest, eastwest andnortheast. The stresses have a characteristic of multiphase structural activities, ofwhich the NE stress is most closely related with mineralize.
3. Based on structure deformation and Superposition, the evolution processesdivided into three periods, i.e., pre-metallogenic, metallogenic and post-metallogenicperiods. The pre-metallogenic period includes pre-Indosinian (D1-2), Indosinian (D3),Early Yanshanian(D4) phrases, metallogenic period does Late Yanshanian (D5-6)phrase, and post-metallogenic period consists of Late Yahshanian(D7) and Himalayanperiod(D8) phrases.
4. The passageway structures for magma and ore-forming fluid and hoststructures for deposits are simple in the Taochong iron deposit. The NE interbedding-fractures occur as major passageway structures for ore-forming fluid, and the sunsidiary-fold as major host structures for deposits.
5. A model for mineralization in the Taochong iron orefield is proposed. Thebasement fault development occurred in the pre-Indosinian, followed by the folddeformation with interbedding fractures occuring in the Indosinian owing to NWstress action. Then the pre-Indosinian basement fault and the Indosinian interbeddingfractures were activated due to the Early Yanshanian stress action, resulted inupwelling of magma from a deep magma chamber. To Late Yanshanian phrase, theinterbedding fractures are further extended, the metallogenic materials from themagma rise and deposit in the interbedding fractures and the turn end of thesunsidiary fold.
通过上述研究，得到以下主要认识：
1、野外调研发现，桃冲地区铁矿床受构造控制作用明显，矿体整体上呈“镰刀形”；矿石主要由镜铁矿、磁铁矿及矽卡岩矿物组成，围岩蚀变主要为矽卡岩化和大理岩化。
2、通过受力分析及岩组图的观察统计，可以确定出桃冲地区主要受到过北西向、东西向及北东向构造应力，且构造应力具有多期次的特征。其中，北东向的构造应力与成矿的关系最为密切。
3、根据构造变形叠加关系将繁昌桃冲地区构造应力演化可分为3期8个阶段：成矿前期，包含前印支期（D1-2）、印支期（D3）、燕山早期（D4）；成矿期，涉及燕山晚期（D5-6）；成矿期后，包含燕山晚期（D7）和喜马拉雅期（D8）。
4、结合区域地质矿产资料，综合分析表明，桃冲地区导岩导矿构造及容矿构造较为简单，主要的导矿构造为北东向的层间断裂，主要的容矿构造为北东向的层间断裂及次级褶皱的转折端部位。
5、在以上资料的基础上，建立了以下构造成矿模型：前印支期区内主要形成基底断裂；印支期在北西向应力作用下区内发生褶皱变形并伴随层间滑脱；在燕山早期构造应力的诱发下，前印支期基底断裂和印支期层间断裂发生活化，沟通深部岩浆房，导致岩浆上涌；至燕山晚期，层间断裂进一步张裂，岩浆晚期分异出的成矿物质上升充填在层间断裂及次级褶皱转折端形成矿体。
Taochong orefield is located in the northeast of the Tongling-Fanchang oreconcentration area, which is an important segment of the Lower and Middle Yangtzeiron-copper-gold metallogenic belt, and evidently controlled by structures. Fieldinvestigation and measurement have been carried out on the folds, faults, joints andcleavages in the orefield, with determination on the principal stress directions of themultiphase structural activities through deformation characteristics observation andstructural set analysis. On the basis of the study, an analysis has been completed onthe evolution of tectonic stress field in the orefield and its significance in controllingof ore deposits, a model proposed for mineralization in the Taochong orefield, and aprediction done on the favorable locations for iron deposits concentration in theorefield based on the model.
The following are major achievements obtained in this thesis:
1. Taochong orefield is evidently controlled by structures, and the ore bodyoccurs as falciform. Ores consist of specularite, magnetite and skarn-minerals andwall alteration includes skarnization and marbleization.
2. Through the stress analysis and the petrotectonics observation, the principalstress directions in Taochong orefield are determined as northwest, eastwest andnortheast. The stresses have a characteristic of multiphase structural activities, ofwhich the NE stress is most closely related with mineralize.
3. Based on structure deformation and Superposition, the evolution processesdivided into three periods, i.e., pre-metallogenic, metallogenic and post-metallogenicperiods. The pre-metallogenic period includes pre-Indosinian (D1-2), Indosinian (D3),Early Yanshanian(D4) phrases, metallogenic period does Late Yanshanian (D5-6)phrase, and post-metallogenic period consists of Late Yahshanian(D7) and Himalayanperiod(D8) phrases.
4. The passageway structures for magma and ore-forming fluid and hoststructures for deposits are simple in the Taochong iron deposit. The NE interbedding-fractures occur as major passageway structures for ore-forming fluid, and the sunsidiary-fold as major host structures for deposits.
5. A model for mineralization in the Taochong iron orefield is proposed. Thebasement fault development occurred in the pre-Indosinian, followed by the folddeformation with interbedding fractures occuring in the Indosinian owing to NWstress action. Then the pre-Indosinian basement fault and the Indosinian interbeddingfractures were activated due to the Early Yanshanian stress action, resulted inupwelling of magma from a deep magma chamber. To Late Yanshanian phrase, theinterbedding fractures are further extended, the metallogenic materials from themagma rise and deposit in the interbedding fractures and the turn end of thesunsidiary fold.
引文
Maher K C. Skarn alteration and mineralization at Coroccohuayco,Tintaya District, Peru.Economic Geology,2010,105(2):263-283.
Mao J W, Wang Y T, Lehmann B, Yu J J, Du A D, Mei Y X, Li Y F, Zang W S, Stein H J and ZhouT F. Molybdenite Re-Os and albite40Ar-39Ar dating of Cu Au Mo and magnetite porphyrysystems in the Yangtze River valley and metallogenic implications. Ore Geology Reviews,2006a,29:307-324.
Meinert L D, Dipple G M, Nicolescu S. World skarn deposits. Economic Geology, one hundredthanniversary volume,2005:1-336.
Pan Yuanming, Dong Ping. The Lower Changjiang (Yangzi/Yangtze River) metallogenic belt, eastcentral China: intrusion and wall rock-hosted Cu-Fe-Au, Mo, Zn, Pb, Ag deposits. OreGeology Reviews,1999,15(4):177-242.
Wu Ganguo, Zhang Da, Zang Wenshuan. Study of tectonic layering motion and layeringmineralization in the Tongling metallogenic cluster. Science in China (Series D),2003,46(8):853-863.
Xiao Xinjian, Gu Lianxing, Ni Pei. Multi-episode fluid boiling in the Shizishan copper-golddeposit at Tongling, Anhui Province: its bearing on ore formation. Science in China (SeriesD),2002,45(1):34-44.
Zhao Yiming, Dong Yongguan, Li Daxin, Bi Chengsi. Geology, mineralogy, geochemistry, andzonation of the Bajiazi dolost one-hosted Zn-Pb-Ag skarn deposit, Liaoning Province,China.Ore Geology Reviews,2003,23(3-4):153-182.
常印佛,刘湘培,吴言昌.长江中下游铜铁成矿带.北京:地质出版社,1991:1-379.
陈国达.成矿构造研究法.北京:地质出版社,1983:1-421.
陈沪生.扬子准地台下扬子盆地HQ-13地球物理-地质综合解释纲要.见:欧庆贤主编,中国南方油勘查新领域探索论文集（第2辑）.北京:地质出版社,1988:239~250.
陈正乐,杨农,王平安,宫红良,韩凤彬,周永贵,邵飞,唐湘生,徐金山,喻建发.江西临川地区相山铀矿田构造应力场分析.地质通报,2011,30(4):514-531.
杜杨松,秦新龙,李铉具.安徽铜陵地区中生代岩浆底侵作用——来自岩石包体和矿物巨晶的证据[J].岩石矿物学杂志,2004,23(2):109-116.
杜杨松，李顺庭，曹毅等，安徽铜陵铜官山矿区中生代侵入岩的形成过程——岩浆底侵、同化混染和分离结晶[J].现代地质，21(1):71-77.
杜杨松，曹毅，张智宇等，安徽沿江地区中生代原地和异地矽卡岩岩浆一热液成矿作用[J]。矿物岩石地球化学通报，30(增刊)：185-190.
董树文,邱瑞龙.安庆-月山地区构造作用与岩浆活动.北京:地质出版社,1993:1~141.
胡玲,刘俊来,纪沫等.变形显微构造识别手册.北京:地质出版社,2009:1-180.
何永年,林传勇,史兰斌.构造岩石学基础.北京:地质出版社,1988:1-180.
刘文灿,李东旭,高德臻.铜陵地区构造变形系统复合时序及复合效应分析.地质力学学报,1996,2(1):42-48.
楼亚儿,杜杨松.安徽繁昌中生代侵入岩的特征和锆石SHRIMP测年.地球化学,2006,35(4):333-345.
楼亚儿.安徽繁昌中生代侵入岩的特征和成因研究：[博士学位论文].北京:中国地质大学,2005.
毛景文,邵拥军,谢桂青,张建东,陈毓川.长江中下游成矿带铜陵矿集区铜多金属矿床模型.矿床地质,2009,28(2):109-119.
倪若水,王道华.繁昌桃冲铁矿成因探讨.矿床地质,1983,2(3):16-23.
卜保全,洪东良,刘晓明.皖南桃冲铁矿床成因探讨.昆明冶金高等专科学校学报,2002,18(3):23-25.
卜保全,韩赟,戴琛.安徽省繁昌县桃冲铁矿接替资源勘查（普查）报告.2011.
唐永成,吴言昌,储国正,邢凤鸣,王永敏,曹奋扬,常印佛.安徽沿江地区铜多金属矿床地质.北京:地质出版社,1998:1-351.
王彪,王核,任广利,刘建平,赵玲.安徽南部桃冲地区铁矿床控矿构造分析.大地构造与成矿学,2010,34(3):362-367.
王玉林,李中樱,王允.繁昌地区富铁矿成矿特征分析.矿业快报,2007,462(10):75-77.
邢凤鸣,徐祥,李志昌.长江中下游早元古代基底的发现及意义.科学通报,1993,38(27):1883~1886.
翟裕生,姚书振,林新多,周珣若,万天丰,金福全,周宗桂.长江中下游地区铁铜（金）成矿规律.北京:地质出版社,1992:1-235.
翟裕生,林新多.矿田构造学.北京:地质出版社,1993:1-212.
翟裕生等著.长江中下游铜金矿床矿田构造[M].北京:地质出版社,1999:1-194.
张达,李东旭.铜陵凤凰山矿田成矿构造应力场模拟研究.地质力学学报,1998,4(2):91-96.
赵斌,李院生,赵劲松.岩浆成因矽卡岩的包裹体证据.地球化学,1995,24(2):198~201.
赵一鸣,林文蔚,毕承思,李大新,蒋崇俊.中国矽卡岩矿床.北京:地质出版社,1990:1-354.
周旭信.安徽省顺风山铁矿矿床地质特征及成因分析.地质与勘探,2002,38(1):31-34.
朱志澄.构造地质学.北京:地质出版社,1999:1-262.
Mao J W, Wang Y T, Lehmann B, Yu J J, Du A D, Mei Y X, Li Y F, Zang W S, Stein H J and ZhouT F. Molybdenite Re-Os and albite40Ar-39Ar dating of Cu Au Mo and magnetite porphyrysystems in the Yangtze River valley and metallogenic implications. Ore Geology Reviews,2006a,29:307-324.
Meinert L D, Dipple G M, Nicolescu S. World skarn deposits. Economic Geology, one hundredthanniversary volume,2005:1-336.
Pan Yuanming, Dong Ping. The Lower Changjiang (Yangzi/Yangtze River) metallogenic belt, eastcentral China: intrusion and wall rock-hosted Cu-Fe-Au, Mo, Zn, Pb, Ag deposits. OreGeology Reviews,1999,15(4):177-242.
Wu Ganguo, Zhang Da, Zang Wenshuan. Study of tectonic layering motion and layeringmineralization in the Tongling metallogenic cluster. Science in China (Series D),2003,46(8):853-863.
Xiao Xinjian, Gu Lianxing, Ni Pei. Multi-episode fluid boiling in the Shizishan copper-golddeposit at Tongling, Anhui Province: its bearing on ore formation. Science in China (SeriesD),2002,45(1):34-44.
Zhao Yiming, Dong Yongguan, Li Daxin, Bi Chengsi. Geology, mineralogy, geochemistry, andzonation of the Bajiazi dolost one-hosted Zn-Pb-Ag skarn deposit, Liaoning Province,China.Ore Geology Reviews,2003,23(3-4):153-182.
常印佛,刘湘培,吴言昌.长江中下游铜铁成矿带.北京:地质出版社,1991:1-379.
陈国达.成矿构造研究法.北京:地质出版社,1983:1-421.
陈沪生.扬子准地台下扬子盆地HQ-13地球物理-地质综合解释纲要.见:欧庆贤主编,中国南方油勘查新领域探索论文集（第2辑）.北京:地质出版社,1988:239~250.
陈正乐,杨农,王平安,宫红良,韩凤彬,周永贵,邵飞,唐湘生,徐金山,喻建发.江西临川地区相山铀矿田构造应力场分析.地质通报,2011,30(4):514-531.
杜杨松,秦新龙,李铉具.安徽铜陵地区中生代岩浆底侵作用——来自岩石包体和矿物巨晶的证据[J].岩石矿物学杂志,2004,23(2):109-116.
杜杨松，李顺庭，曹毅等，安徽铜陵铜官山矿区中生代侵入岩的形成过程——岩浆底侵、同化混染和分离结晶[J].现代地质，21(1):71-77.
杜杨松，曹毅，张智宇等，安徽沿江地区中生代原地和异地矽卡岩岩浆一热液成矿作用[J]。矿物岩石地球化学通报，30(增刊)：185-190.
董树文,邱瑞龙.安庆-月山地区构造作用与岩浆活动.北京:地质出版社,1993:1~141.
胡玲,刘俊来,纪沫等.变形显微构造识别手册.北京:地质出版社,2009:1-180.
何永年,林传勇,史兰斌.构造岩石学基础.北京:地质出版社,1988:1-180.
刘文灿,李东旭,高德臻.铜陵地区构造变形系统复合时序及复合效应分析.地质力学学报,1996,2(1):42-48.
楼亚儿,杜杨松.安徽繁昌中生代侵入岩的特征和锆石SHRIMP测年.地球化学,2006,35(4):333-345.
楼亚儿.安徽繁昌中生代侵入岩的特征和成因研究：[博士学位论文].北京:中国地质大学,2005.
毛景文,邵拥军,谢桂青,张建东,陈毓川.长江中下游成矿带铜陵矿集区铜多金属矿床模型.矿床地质,2009,28(2):109-119.
倪若水,王道华.繁昌桃冲铁矿成因探讨.矿床地质,1983,2(3):16-23.
卜保全,洪东良,刘晓明.皖南桃冲铁矿床成因探讨.昆明冶金高等专科学校学报,2002,18(3):23-25.
卜保全,韩赟,戴琛.安徽省繁昌县桃冲铁矿接替资源勘查（普查）报告.2011.
唐永成,吴言昌,储国正,邢凤鸣,王永敏,曹奋扬,常印佛.安徽沿江地区铜多金属矿床地质.北京:地质出版社,1998:1-351.
王彪,王核,任广利,刘建平,赵玲.安徽南部桃冲地区铁矿床控矿构造分析.大地构造与成矿学,2010,34(3):362-367.
王玉林,李中樱,王允.繁昌地区富铁矿成矿特征分析.矿业快报,2007,462(10):75-77.
邢凤鸣,徐祥,李志昌.长江中下游早元古代基底的发现及意义.科学通报,1993,38(27):1883~1886.
翟裕生,姚书振,林新多,周珣若,万天丰,金福全,周宗桂.长江中下游地区铁铜（金）成矿规律.北京:地质出版社,1992:1-235.
翟裕生,林新多.矿田构造学.北京:地质出版社,1993:1-212.
翟裕生等著.长江中下游铜金矿床矿田构造[M].北京:地质出版社,1999:1-194.
张达,李东旭.铜陵凤凰山矿田成矿构造应力场模拟研究.地质力学学报,1998,4(2):91-96.
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