江西相山铀矿田古火山口探讨
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摘要
江西相山火山盆地发育我国第一大、世界第三大火山岩型铀矿田,盆地盖层主要为早白垩世流纹英安岩和碎斑熔岩,这两套火山岩亦是研究区内主要的赋矿岩石,与铀多金属矿化有关的垂向蚀变幅度达千米。近年来,相山铀矿田地质勘查取得了令人瞩目的进展,然而对于矿床的成因及产状等方面仍存在争论,部分原因在于,对流纹英安岩和碎斑熔岩的火山机构研究不够深入。通过对相山矿田的遥感地质解译、碎斑熔岩流动构造测量、磁化率各向异性(AMS)及大地电磁测量(MT)等研究,获得火山通道位置。相山火山盆地流动构造不发育,根据火山集块岩、熔岩中出露的变质岩捕掳体及其长轴统计,结合AMS数据,指示鹅湖岭期碎斑熔岩主火山口位于相山顶,河元背、严坑、柏昌和如意亭为4个次级火山口,而书塘地区可能是打鼓顶期流纹英安岩的火山通道所在。这些推测的火山口在遥感影像上得到环形、放射状构造的印证。相山火山盆地19条MT剖面显示:盆地基底变质岩系与上覆火山岩盖层之间呈连续的水平低阻异常带,不整合界面清晰;打鼓顶组火山岩呈似层状产出,主要分布于盆地西部,并在河元背-船坑-杏树下一带识别出近东西走向的厚层流纹英安岩凹槽;鹅湖岭组火山岩总体呈蘑菇状,中心位置(相山主峰)发育自下而上贯通式的低阻异常,推测为鹅湖岭组碎斑熔岩喷发的通道相(火山颈相)。综合研究表明,相山地区打鼓顶期主要火山通道位于相山顶或其西侧书塘地区,可能存在河元背次级岩浆通道;鹅湖岭期火山活动主岩浆通道位于相山顶,次岩浆通道位于河元背、阳家山、严坑和柏昌,岩浆通道具有继承性和发展性。
The Xiangshan volcanic basin in Jiangxi province is the largest volcano-type uranium deposit in China and the third largest in the world. Having been investigated for over 60 years, the total drilling core in the basin exceeds 2 million meters. The main lithology of the basin is the Early Cretaceous rhyodacite and porphyroclastic lava,accompanied with intrusive rocks. The volcanic rocks are the major ore-bearing rocks, and alteration related to the uranium and associated Pb-Zn mineralization is up to 1000 meters thick vertically. In recent years, remarkable progress has been made in geological exploration. A number of new deposits and mineralization sites have been found, and the old ones continuously expanded. However, it is still controversy regarding the origin and location of deposits, mainly because of the volcanic calderas location of rhyodacite and porphyroclastic lava is still unclear. Remote sensing,magnetic susceptibility anisotropy(AMS) and magnetotelluric(MT) measurements of rhyodacite and porphyroclastic lava in the basin have been conducted to determine the volcanic calderas locations. The results show that the flow structure of the Xiangshan volcanic basin is not well developed. According to the outcrops of volcanic agglomerate and metamorphic rocks in the field, it seems that there are three volcanic calderas for the porphyroclastic lava. The AMS data suggest that the craters located at the summit of Xiangshan, Yankeng, Heyuanbei, Ruyiting and Baichang, whereas the Shitang area may be the volcanic vent of rhyodacite. The 19 MT sections across the volcanic basin show that there is a continuous horizontal low resistivity anomaly belt between the metamorphic basement and the overlying volcanic covers. In the area of Heyuanbei-Chuankeng-Xingshuxia, a thick east-west-strike rhyodacite dimple is identified. The main uranium deposits are distributed in the concave or nearby. The general morphology of volcanic rocks of the Ehuhuling Formation is mushroom-shaped, and is thick in the central part of the basin. A low-resistivity anomaly from bottom to top is found within a radius of about 2 km from the Xiangshan main peak. It was thought to be eruption of the channel phase(volcanic neck phase). The volcanic neck was steep tubular, dip to the south. The late granite porphyry was a combination of dikes and bedrock, forming an annular rock mass opening to the west. On the whole, the volcanic calderas of rhyodacite was located in the Xiangshan main peak or Shutang area, and there may be a Heyuanbei secondary magma channel. The main magmatic channel of the Ehulling period is located at the Xiangshan main peak and sub-magma channel located in Heyuanbei, Yangjiashan(Furongshan), Yankeng and Bochang.
The Xiangshan volcanic basin in Jiangxi province is the largest volcano-type uranium deposit in China and the third largest in the world. Having been investigated for over 60 years, the total drilling core in the basin exceeds 2 million meters. The main lithology of the basin is the Early Cretaceous rhyodacite and porphyroclastic lava,accompanied with intrusive rocks. The volcanic rocks are the major ore-bearing rocks, and alteration related to the uranium and associated Pb-Zn mineralization is up to 1000 meters thick vertically. In recent years, remarkable progress has been made in geological exploration. A number of new deposits and mineralization sites have been found, and the old ones continuously expanded. However, it is still controversy regarding the origin and location of deposits, mainly because of the volcanic calderas location of rhyodacite and porphyroclastic lava is still unclear. Remote sensing,magnetic susceptibility anisotropy(AMS) and magnetotelluric(MT) measurements of rhyodacite and porphyroclastic lava in the basin have been conducted to determine the volcanic calderas locations. The results show that the flow structure of the Xiangshan volcanic basin is not well developed. According to the outcrops of volcanic agglomerate and metamorphic rocks in the field, it seems that there are three volcanic calderas for the porphyroclastic lava. The AMS data suggest that the craters located at the summit of Xiangshan, Yankeng, Heyuanbei, Ruyiting and Baichang, whereas the Shitang area may be the volcanic vent of rhyodacite. The 19 MT sections across the volcanic basin show that there is a continuous horizontal low resistivity anomaly belt between the metamorphic basement and the overlying volcanic covers. In the area of Heyuanbei-Chuankeng-Xingshuxia, a thick east-west-strike rhyodacite dimple is identified. The main uranium deposits are distributed in the concave or nearby. The general morphology of volcanic rocks of the Ehuhuling Formation is mushroom-shaped, and is thick in the central part of the basin. A low-resistivity anomaly from bottom to top is found within a radius of about 2 km from the Xiangshan main peak. It was thought to be eruption of the channel phase(volcanic neck phase). The volcanic neck was steep tubular, dip to the south. The late granite porphyry was a combination of dikes and bedrock, forming an annular rock mass opening to the west. On the whole, the volcanic calderas of rhyodacite was located in the Xiangshan main peak or Shutang area, and there may be a Heyuanbei secondary magma channel. The main magmatic channel of the Ehulling period is located at the Xiangshan main peak and sub-magma channel located in Heyuanbei, Yangjiashan(Furongshan), Yankeng and Bochang.
引文
陈正乐,陈柏林,潘家永.2015.江西相山铀矿床成矿规律总结研究.北京:地质出版社:1-137.
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.2011.江西临川地区相山铀矿田构造应力场分析.地质通报,30(4):514-531.
方锡珩,侯文尧,万国良.1982.相山破火山口火山杂岩体的岩石学研究.岩矿测试,1(1):1-10.
郭福生,林子瑜,黎广荣,邓居智,谢财富,杨海燕,吴志春,周万蓬,姜勇彪,李红星,方根显.2017.江西相山火山盆地地质结构研究:来自大地电磁测深及三维地质建模的证据.地球物理学报,60(4):1491-1510.
郭福生,杨庆坤,孟祥金,谢财富,时国,陈留勤,蒋振频,曾涛,罗能辉.2016.江西相山酸性火山-侵入杂岩体地球化学特征与岩石成因.地质学报,90(4):769-784.
郭福生,杨庆坤,谢财富,孟祥金,周万蓬,姜勇彪,张树明,吴志春.2015.江西相山酸性火山-侵入杂岩精确年代学与演化序列研究.地质科学,50(3):684-707.
胡宝群,邱林飞,李满根,孙占学,吕古贤,周义朋,白丽红.2015.江西相山铀矿田构造-岩浆演化及其成矿规律.地学前缘,22(4):29-36.
李邦达.1993.江西相山碎斑熔岩成因及其控矿作用的讨论.地质论评,39(2):101-110.
林子瑜,李子颖,龙期华,张士红.2013.相山铀矿田三维地质新认识.铀矿地质,29(4):199-207.
毛建仁,叶海敏,厉子龙,刘凯,邱瑞昭,胡逸州,赵希林,周静.2013.钦杭结合带(东段)晚中生代挤压-伸展构造的岩浆活动与成矿记录.矿物学报,33(S2):30-31.
毛景文,陈懋弘,袁顺达,郭春丽.2011.华南地区钦杭成矿带地质特征和矿床时空分布规律.地质学报,85(5):636-658.
邱爱金.2001.江西相山铀矿田东西向隐伏构造的发现及其地质意义.地质论评,47(6):637-641.
陶奎元.1992.中国东南大陆沿海火山带研究的新进展.地质科技情报,(4):16-22.
魏祥荣,龙期华.1996.遥感、重力资料在相山盆地铀控矿构造分析中的应用.国土资源遥感,(2):37-44.
吴仁贵.1999.相山地区如意亭剖面火山建造特征.华东地质学院学报,(3):201-208.
吴仁贵,余达淦,张树明.2003.相山铀矿田流纹英安斑岩的厘定及与铀矿化的关系.铀矿地质,19(2):81-87.
谢国发,姚亦军,李芳,刘牛明.2015.江西居隆庵矿床//张金带,李子颖,徐高中,彭云彪,王果.我国铀矿勘查的重大进展和突破.北京:地质出版社:264.
杨水源,蒋少涌,姜耀辉,赵葵东,范洪海.2010.江西相山流纹英安岩和流纹英安斑岩锆石U-Pb年代学和Hf同位素组成及其地质意义.中国科学:地球科学,40(8):953-969.
杨水源,蒋少涌,赵葵东,姜耀辉,凌洪飞,陈培荣.2013.江西相山铀矿田如意亭剖面火山岩的年代学格架及其地质意义.岩石学报,29(12):4362-4372.
张万良.2012.相山矿田铀矿地质研究进展与趋势.资源调查与环境,33(1):22-27.
张万良.2015.相山铀矿田矿体形态分类及成因意义.大地构造与成矿学,39(5):844-854.
周万蓬.2015.相山火山盆地三维地质调查.东华理工大学技术报告.
周万蓬,郭福生,刘林清,姜勇彪.2015.中国东南部碎斑熔岩问题再探讨.资源调查与环境,36(2):98-103.
Shu L S,Wang B,Cawood P A,Santosh M and Xu Z Q.2015.Early Paleozoic and early Mesozoic intraplate tectonic and magmatic events in the Cathaysia Block,south china.Tectonics,34(8):1600-1621.
Thompson N,Bennett M and Petford N.2008.Emplacement of volcanic debris landslide deposits:New insight from distinct element numerical simulations.AGU Fall Meeting Abstracts:198.
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.2011.江西临川地区相山铀矿田构造应力场分析.地质通报,30(4):514-531.
方锡珩,侯文尧,万国良.1982.相山破火山口火山杂岩体的岩石学研究.岩矿测试,1(1):1-10.
郭福生,林子瑜,黎广荣,邓居智,谢财富,杨海燕,吴志春,周万蓬,姜勇彪,李红星,方根显.2017.江西相山火山盆地地质结构研究:来自大地电磁测深及三维地质建模的证据.地球物理学报,60(4):1491-1510.
郭福生,杨庆坤,孟祥金,谢财富,时国,陈留勤,蒋振频,曾涛,罗能辉.2016.江西相山酸性火山-侵入杂岩体地球化学特征与岩石成因.地质学报,90(4):769-784.
郭福生,杨庆坤,谢财富,孟祥金,周万蓬,姜勇彪,张树明,吴志春.2015.江西相山酸性火山-侵入杂岩精确年代学与演化序列研究.地质科学,50(3):684-707.
胡宝群,邱林飞,李满根,孙占学,吕古贤,周义朋,白丽红.2015.江西相山铀矿田构造-岩浆演化及其成矿规律.地学前缘,22(4):29-36.
李邦达.1993.江西相山碎斑熔岩成因及其控矿作用的讨论.地质论评,39(2):101-110.
林子瑜,李子颖,龙期华,张士红.2013.相山铀矿田三维地质新认识.铀矿地质,29(4):199-207.
毛建仁,叶海敏,厉子龙,刘凯,邱瑞昭,胡逸州,赵希林,周静.2013.钦杭结合带(东段)晚中生代挤压-伸展构造的岩浆活动与成矿记录.矿物学报,33(S2):30-31.
毛景文,陈懋弘,袁顺达,郭春丽.2011.华南地区钦杭成矿带地质特征和矿床时空分布规律.地质学报,85(5):636-658.
邱爱金.2001.江西相山铀矿田东西向隐伏构造的发现及其地质意义.地质论评,47(6):637-641.
陶奎元.1992.中国东南大陆沿海火山带研究的新进展.地质科技情报,(4):16-22.
魏祥荣,龙期华.1996.遥感、重力资料在相山盆地铀控矿构造分析中的应用.国土资源遥感,(2):37-44.
吴仁贵.1999.相山地区如意亭剖面火山建造特征.华东地质学院学报,(3):201-208.
吴仁贵,余达淦,张树明.2003.相山铀矿田流纹英安斑岩的厘定及与铀矿化的关系.铀矿地质,19(2):81-87.
谢国发,姚亦军,李芳,刘牛明.2015.江西居隆庵矿床//张金带,李子颖,徐高中,彭云彪,王果.我国铀矿勘查的重大进展和突破.北京:地质出版社:264.
杨水源,蒋少涌,姜耀辉,赵葵东,范洪海.2010.江西相山流纹英安岩和流纹英安斑岩锆石U-Pb年代学和Hf同位素组成及其地质意义.中国科学:地球科学,40(8):953-969.
杨水源,蒋少涌,赵葵东,姜耀辉,凌洪飞,陈培荣.2013.江西相山铀矿田如意亭剖面火山岩的年代学格架及其地质意义.岩石学报,29(12):4362-4372.
张万良.2012.相山矿田铀矿地质研究进展与趋势.资源调查与环境,33(1):22-27.
张万良.2015.相山铀矿田矿体形态分类及成因意义.大地构造与成矿学,39(5):844-854.
周万蓬.2015.相山火山盆地三维地质调查.东华理工大学技术报告.
周万蓬,郭福生,刘林清,姜勇彪.2015.中国东南部碎斑熔岩问题再探讨.资源调查与环境,36(2):98-103.
Shu L S,Wang B,Cawood P A,Santosh M and Xu Z Q.2015.Early Paleozoic and early Mesozoic intraplate tectonic and magmatic events in the Cathaysia Block,south china.Tectonics,34(8):1600-1621.
Thompson N,Bennett M and Petford N.2008.Emplacement of volcanic debris landslide deposits:New insight from distinct element numerical simulations.AGU Fall Meeting Abstracts:198.
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