兰坪盆地区域地球化学异常特征及找矿方向
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摘要
西南三江中段兰坪盆地是著名的金属成矿区,区内矿产资源丰富,以铜、铅、锌、银为主。2012—2016年云南省地质调查院完成了1∶25万丽江市幅水系沉积物测量工作,平均采样密度为1. 02个/km~2,采样介质为代表汇水域基岩成分的岩屑,样品粒级为-10～+60目。以兰坪盆地内的1∶25万水系沉积物测量成果为基础,首先分析了盆地内微量元素的地球化学特征,指出仅从元素富集系数的大小来判断研究区内有利矿种的方法欠妥;进而为消除元素的风化富集效应而采用变值七级异常划分方案绘制了该区地球化学异常图,并对区内的主要成矿元素进行异常圈定和分级评价。结果表明所圈定的异常区不仅与该区典型矿床在空间上相吻合,而且单元素异常级别或平均异常强度也与矿床的规模相一致,已知矿床均位于平均异常强度达3级以上的异常区。除典型已知矿区外,区域地球化学异常特征显示兰坪盆地东北部老君山地区和盆地中南部白洋厂南部地区是盆地内寻找多金属矿床的有利地段。
The Lanping basin located in the middle section of the Sanjiang range in southwest China is a famous polymetallic mineralization area in which dominant economic metals are copper,lead,zinc,and silver. The regional geochemistry survey with the scale of 1∶ 250 000 has been completed by Yunnan Geological Survey Institute from 2012 to 2016 in this area. The sampling medium is stream sediment with the size of-10 to + 60 meshes,and the averaged sampling density is ca. 1. 02 per square kilometer. Based on the analytical results of the regional geochemistry survey,the enrichment coefficients of 29 trace elements on average concentration in the study area are calculated relative to their average background values in the Southwest Sanjiang ore zone and discussed focusing on the main economic metals firstly. The results indicate that it is not suitable to determine economic metals only depending on the enrichment coefficients. Then geochemical anomalies of 29 trace elements are determined and classified in the Lanping basin with an area of 8 800 km~2 on the method of seven levels' classification to eliminate the elemental enrichment effects during weathering. The results indicate that the determined anomaly areas are consistent with the known metal deposits spatially and metal deposits with larger scales are commonly located in the anomaly areas with higher levels. The known metal deposits in this area are commonly located in the anomaly areas with levels higher than 3 on the seven levels' classification method. According to this criterion,two favorable areas are determined for future prospecting for polymetallic deposits. One is the Laojunshan area in the northeast of the basin,and the other is the south section of Baiyangchang area in central-south of the Lanping basin of Yunnan province,China.
The Lanping basin located in the middle section of the Sanjiang range in southwest China is a famous polymetallic mineralization area in which dominant economic metals are copper,lead,zinc,and silver. The regional geochemistry survey with the scale of 1∶ 250 000 has been completed by Yunnan Geological Survey Institute from 2012 to 2016 in this area. The sampling medium is stream sediment with the size of-10 to + 60 meshes,and the averaged sampling density is ca. 1. 02 per square kilometer. Based on the analytical results of the regional geochemistry survey,the enrichment coefficients of 29 trace elements on average concentration in the study area are calculated relative to their average background values in the Southwest Sanjiang ore zone and discussed focusing on the main economic metals firstly. The results indicate that it is not suitable to determine economic metals only depending on the enrichment coefficients. Then geochemical anomalies of 29 trace elements are determined and classified in the Lanping basin with an area of 8 800 km~2 on the method of seven levels' classification to eliminate the elemental enrichment effects during weathering. The results indicate that the determined anomaly areas are consistent with the known metal deposits spatially and metal deposits with larger scales are commonly located in the anomaly areas with higher levels. The known metal deposits in this area are commonly located in the anomaly areas with levels higher than 3 on the seven levels' classification method. According to this criterion,two favorable areas are determined for future prospecting for polymetallic deposits. One is the Laojunshan area in the northeast of the basin,and the other is the south section of Baiyangchang area in central-south of the Lanping basin of Yunnan province,China.
引文
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[10]徐墨寒,薛传东,杨天南,等.兰坪盆地西缘大宗铜矿区容矿火山岩LA-ICP-MS锆石U-Pb年代学及地质意义[J].岩石矿物学杂志,2016,35(5):735-750.
[11]朱华平,范文玉,高大发,等.西南三江成矿带中南段铅锌矿床成矿系列[J].沉积与特提斯地质,2008,28(4):62-68.
[12]朱多录.云南兰坪矿集区成矿系列及成矿规律[J].地质找矿论丛,2013,28(2):224-229.
[13]江彪,邓军,张长青.西南三江地区沉积岩容矿型铅锌矿成矿特征和成矿规律[J].地质学报,2014,88(12):2532-2544.
[14]肖高强,张小兵,李忠,等.因子分析在1∶25万丽江市幅区域地球化学数据解释中的应用[J].云南大学学报(自然科学版),2017,29(S2):175-179.
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[16]张锦让,温汉捷,裘愉卓,等.兰坪盆地西缘沉积岩容矿脉状Cu-Ag(±Pb-Zn)多金属矿床成矿流体特征[J].矿床地质,2015,34(3):497-520.
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[18]牟传龙,王剑,余谦,等.兰坪中新生代沉积盆地演化[J].矿物岩石,1999,19(3):30-36.
[19]付修根.兰坪陆相盆地演化与金属矿床的形成[J].地球科学与环境学报,2005,27(2):26-32.
[20]刘俊来,王安建,曹殿华,等.三江造山带后碰撞断裂构造带的结构与演化:以新生代剑川—兰坪盆地为例[J].高校地质学报,2004,10(4):488-499.
[21]张乾,绍树勋,刘家军,等.兰坪盆地大型矿集区多金属矿床的铅同位素组成及铅的来源[J].矿物学报,2002,22(2):147-154.
[22]苏学军,张家云,肖玲,等. 1∶25万福贡县幅、丽江市幅区域地质调查报告[R].昆明:云南省地质调查院,2008:1-314.
[23]陈开旭,何龙清,杨振强,等.云南兰坪三山—白秧坪铜银多金属成矿富集区的碳氧同位素地球化学[J].华南地质与成矿,2000(4):1-8.
[24]何龙清,陈开旭,魏君奇.云南白秧坪地区东成矿带矿床地球化学特征及成因分析[J].矿床地质,2005,24(1):61-70.
[25]刘家军,翟德高,李志明,等.兰坪盆地白秧坪银铜多金属矿集区中银、钴、铋、镍的赋存状态与成因意义[J].岩石学报,2010,26(6):1646-1660.
[26]王晓虎,侯增谦,宋玉财,等.兰坪盆地白秧坪铅锌铜银多金属矿床:成矿年代及区域成矿作用[J].岩石学报,2011,27(9):2625-2634.
[27]王光辉,宋玉财,侯增谦,等.兰坪盆地连城脉状铜矿床辉钼矿Re-Os定年及其地质意义[J].矿床地质,2009,28(4):413-424.
[28]刘家军,李志明,刘玉平,等.滇西金满脉状铜矿床成矿年龄讨论[J].现代地质,2003,17(1):34-39.
[29]薛春纪,陈毓川,王登红,等.滇西北金顶和白秧坪矿床:地质和He,Ne,Xe同位素组成及成矿时代[J].中国科学:D辑,2003,33(4):315-322.
[30]牟传龙,余谦.金顶铅锌矿床相关地质问题及成因探讨[J].矿物岩石,2004,24(1):48-51.
[31]史长义,梁萌,冯斌.中国水系沉积物39种元素系列背景值[J].地球科学,2016,41(2):234-251.
[32] GONG Q J,LI J Z,XIANG Y C,et al. Determination and classification of geochemical anomalies based on backgrounds and cutoff grades of trace elements:A case study in South Nanling Range,China[J]. Journal of Geochemical Exploration,2018,194:44-51.
[33] GONG Q J,DENG J,WANG C M,et al. Element behaviors due to rock weathering and its implication to geochemical anomaly recognition:A case study on Linglong biotite granite in Jiaodong peninsula,China[J]. Journal of Geochemical Exploration,2013,128:14-24.
[34]马云涛,龚庆杰,韩东昱,等.安山岩风化过程中元素行为——以豫西熊耳山地区为例[J].地质与勘探,2015,51(3):545-554.
[35] LI J Z,GONG Q J,YAN T T,et al. Quantitative description of geochemical backgrounds of gold due to rock weathering in Jiaodong peninsula,China[J]. Journal of Geochemical Exploration,2018,192:155-162.
[36]向运川,牟绪赞,任天祥,等.全国矿产资源潜力评价化探资料应用研究[M].北京:地质出版社,2018:1-445.
[37]许胜超.南岭东段区域化探异常分析[D].北京:中国地质大学(北京),2016:5.
[38] GONG Q J,DENG J,JIA Y J,et al. Empirical equations to describe trace element behaviors due to rock weathering in China[J]. Journal of Geochemical Exploration,2015,152:110-117.
[2]徐启东,李建威.云南兰坪北部铜多金属矿化成矿流体流动与矿化分带:流体包裹体和稳定同位素依据[J].矿床地质,2003,22(4):365-376.
[3]杨伟光,喻学惠,李文昌,等.云南白秧坪银多金属矿集区成矿流体特征及成矿机制[J].现代地质,2003,17(1):27-33.
[4]朱志军,郭福生,宋玉财,等.滇西兰坪盆地古近系构造-沉积演化与成矿的关系[J].沉积学报,2014,32(6):997-1006.
[5]沈青强,曹凯,王国灿,等.剑川—兰坪盆地古近系沉积-构造变革及其区域构造意义[J].大地构造与成矿学,2017,41(1):23-41.
[6]王安建,曹殿华,高兰,等.论云南兰坪金顶超大型铅锌矿床的成因[J].地质学报,2009,83(1):43-54.
[7]黄玉凤,曹殿华,王志军,等.云南兰坪盆地北部东缘铅锌矿床喷流沉积成因的厘定:来自矿物学和硫同位素证据[J].地质力学学报,2011,17(1):91-102.
[8]李小明.滇西金满铜矿床成矿年龄测定[J].现代地质,2001,15(4):405-408.
[9]王晓虎,宋玉财,张洪瑞,等.白秧坪铅锌多金属矿集区东矿带成矿地球化学作用与成矿年龄[J].地质力学学报,2016,22(2):294-309.
[10]徐墨寒,薛传东,杨天南,等.兰坪盆地西缘大宗铜矿区容矿火山岩LA-ICP-MS锆石U-Pb年代学及地质意义[J].岩石矿物学杂志,2016,35(5):735-750.
[11]朱华平,范文玉,高大发,等.西南三江成矿带中南段铅锌矿床成矿系列[J].沉积与特提斯地质,2008,28(4):62-68.
[12]朱多录.云南兰坪矿集区成矿系列及成矿规律[J].地质找矿论丛,2013,28(2):224-229.
[13]江彪,邓军,张长青.西南三江地区沉积岩容矿型铅锌矿成矿特征和成矿规律[J].地质学报,2014,88(12):2532-2544.
[14]肖高强,张小兵,李忠,等.因子分析在1∶25万丽江市幅区域地球化学数据解释中的应用[J].云南大学学报(自然科学版),2017,29(S2):175-179.
[15]徐志刚,陈毓川,王登红,等.中国成矿区带划分方案[M].北京:地质出版社,2008:1-138.
[16]张锦让,温汉捷,裘愉卓,等.兰坪盆地西缘沉积岩容矿脉状Cu-Ag(±Pb-Zn)多金属矿床成矿流体特征[J].矿床地质,2015,34(3):497-520.
[17]赵海滨.滇西兰坪盆地中北部铜多金属矿床成矿特征及地质条件[D].北京:中国地质大学(北京),2006:11.
[18]牟传龙,王剑,余谦,等.兰坪中新生代沉积盆地演化[J].矿物岩石,1999,19(3):30-36.
[19]付修根.兰坪陆相盆地演化与金属矿床的形成[J].地球科学与环境学报,2005,27(2):26-32.
[20]刘俊来,王安建,曹殿华,等.三江造山带后碰撞断裂构造带的结构与演化:以新生代剑川—兰坪盆地为例[J].高校地质学报,2004,10(4):488-499.
[21]张乾,绍树勋,刘家军,等.兰坪盆地大型矿集区多金属矿床的铅同位素组成及铅的来源[J].矿物学报,2002,22(2):147-154.
[22]苏学军,张家云,肖玲,等. 1∶25万福贡县幅、丽江市幅区域地质调查报告[R].昆明:云南省地质调查院,2008:1-314.
[23]陈开旭,何龙清,杨振强,等.云南兰坪三山—白秧坪铜银多金属成矿富集区的碳氧同位素地球化学[J].华南地质与成矿,2000(4):1-8.
[24]何龙清,陈开旭,魏君奇.云南白秧坪地区东成矿带矿床地球化学特征及成因分析[J].矿床地质,2005,24(1):61-70.
[25]刘家军,翟德高,李志明,等.兰坪盆地白秧坪银铜多金属矿集区中银、钴、铋、镍的赋存状态与成因意义[J].岩石学报,2010,26(6):1646-1660.
[26]王晓虎,侯增谦,宋玉财,等.兰坪盆地白秧坪铅锌铜银多金属矿床:成矿年代及区域成矿作用[J].岩石学报,2011,27(9):2625-2634.
[27]王光辉,宋玉财,侯增谦,等.兰坪盆地连城脉状铜矿床辉钼矿Re-Os定年及其地质意义[J].矿床地质,2009,28(4):413-424.
[28]刘家军,李志明,刘玉平,等.滇西金满脉状铜矿床成矿年龄讨论[J].现代地质,2003,17(1):34-39.
[29]薛春纪,陈毓川,王登红,等.滇西北金顶和白秧坪矿床:地质和He,Ne,Xe同位素组成及成矿时代[J].中国科学:D辑,2003,33(4):315-322.
[30]牟传龙,余谦.金顶铅锌矿床相关地质问题及成因探讨[J].矿物岩石,2004,24(1):48-51.
[31]史长义,梁萌,冯斌.中国水系沉积物39种元素系列背景值[J].地球科学,2016,41(2):234-251.
[32] GONG Q J,LI J Z,XIANG Y C,et al. Determination and classification of geochemical anomalies based on backgrounds and cutoff grades of trace elements:A case study in South Nanling Range,China[J]. Journal of Geochemical Exploration,2018,194:44-51.
[33] GONG Q J,DENG J,WANG C M,et al. Element behaviors due to rock weathering and its implication to geochemical anomaly recognition:A case study on Linglong biotite granite in Jiaodong peninsula,China[J]. Journal of Geochemical Exploration,2013,128:14-24.
[34]马云涛,龚庆杰,韩东昱,等.安山岩风化过程中元素行为——以豫西熊耳山地区为例[J].地质与勘探,2015,51(3):545-554.
[35] LI J Z,GONG Q J,YAN T T,et al. Quantitative description of geochemical backgrounds of gold due to rock weathering in Jiaodong peninsula,China[J]. Journal of Geochemical Exploration,2018,192:155-162.
[36]向运川,牟绪赞,任天祥,等.全国矿产资源潜力评价化探资料应用研究[M].北京:地质出版社,2018:1-445.
[37]许胜超.南岭东段区域化探异常分析[D].北京:中国地质大学(北京),2016:5.
[38] GONG Q J,DENG J,JIA Y J,et al. Empirical equations to describe trace element behaviors due to rock weathering in China[J]. Journal of Geochemical Exploration,2015,152:110-117.