The genesis of the Chedu gold deposit in Nansha River area, Shaanxi Province
-
摘要:
针对陕西南沙河地区车渡金矿床进行了研究,研究结果表明,中-新元古界碧口群二亚群(Pt2-3bk2)中玄武质火山凝灰岩具Sr、Ba、Rb、Ce、P、Sm相对富集,Ta、Nb、Zr、Hf、Ti相对亏损的特征,显示钙碱性火山弧玄武岩的特点;车渡金矿床具有2种成因类型,一是与中生代逆冲推覆构造形成的韧性剪切带有关的强硅化蚀变岩型金矿,二是与中-新元古界碧口岩群二亚群火山凝灰岩有关的BIF型金矿。单颗粒磁铁矿成分分析认为,车渡含金磁铁石英岩中磁铁矿具有高的TFeO(平均值99.59%)含量和极低的TiO2、MgO、A12O3、MnO含量,指示车渡磁铁石英岩金矿石中条带状磁铁矿属于沉积变质型成因条带状含铁建造。含金磁铁石英岩型金矿石的氢氧同位素显示,δ18O水值为12.34‰~12.45‰(平均值12.40‰),δD值为-112.6‰~-103.5‰(平均值-108.05‰),与鞍山-本溪地区条带状含铁建造型铁矿δD变化范围(-129‰~-75‰)一致,暗示车渡含金磁铁石英岩中石英矿物具有条带状含铁建造特征。
Abstract:In this paper, the research work of the Proterozoic deposit in Nansha River area of Shaanxi Province was carried out, and the results show that the basalt volcanic tuff in Bikou Group 2nd sub-group (Pt2-3bk2) is relatively rich in Sr, Ba, Rb, Ce, P and Sm, and depleted in Ta, Nb, Zr, Hf and Ti, exhibiting characteristics of calcium-alkaline volcanic arc basalt. There are two genetic types of the Proterozoic deposits, one is the strongly silicified rock type gold deposits related to the ductile shear zone formed by the Mesozoic thrust Nappe structure, and the other is the BIF type gold deposits related to the 2nd subgroup volcanic tuff of the Meso-Neo Proterozoic period. According to composition analysis of single granular magnetite, the authors hold that magnetite has high TFeO (99.59% on average) content and very low TiO2, MgO, A12O3 and MnO content in gold magnetic quartz, which indicates that the banded magnetite in the Chedu magnetite quartzite gold ore is of sedimentary metamorphic type, i.e., belonging to quartzite type gold deposit. Hydrogen and oxygen isotope features of gold-bearing magnetite quartzite type gold ore show that δ18O water value is 12.34‰~12.45‰ (12.4‰ on average), and δD value is -112.6‰~-103.5‰ (-108.05‰ on average), consistent with BIF variation range of δD-type iron ore in Anshan-Benxi area (-129‰~-75‰), suggesting that quartz minerals in quartz rocks with gold magnetite have BIF characteristics.
-
-
图 1 研究区大地构造位置图(a,据参考文献[1]修改)和区域地质矿产略图(b)
Figure 1.
图 4 大洋中脊玄武岩标准化微量元素蛛网图(a)和球粒陨石标准化稀土元素配分模式图(b)(标准化值据参考文献[13])
Figure 4.
图 6 大洋中脊玄武岩标准化微量元素蛛网图(a)和PAAS标准化稀土元素配分模式图(b)(标准化值据参考文献[13])
Figure 6.
表 1 车渡金矿体特征
Table 1. List of characteristics of the Chedu gold deposit
矿体编号 赋矿岩石 矿体规模 矿体产状 平均品位/(g.t-1) 蚀变组合 控制长/m 平均厚/m 控制斜深/m 倾向/° 倾角/° AuⅠ-1-1 磁铁石英岩 720 1.59 90 350~15 43~72 6.14 褐(黄)铁矿化、磁铁矿化、孔雀石化、碳酸盐化 AuⅠ-1-2 磁铁石英岩 280 0.82 53 0~15 66~73 1.75 弱褐(黄)铁矿磁化、铁矿化、碳酸盐化 AuⅠ-1-3 磁铁石英岩岩 1400 1.35 30 320~350 66~73 3.14 褐(黄)铁矿磁化、铁矿化、碳酸盐化 AuⅠ-2 磁铁石英岩 1200 1.23 88 350~15 40~71 2.58 褐(黄)铁矿磁化、铁矿化、碳酸盐化 AuⅡ-1 强硅化蚀变岩 160 1.75 40 352 83 1.97 硅化、褐铁矿化、黄铁矿化 AuⅡ-2 强硅化蚀变岩 400 0.84 40 352 83 1.68 硅化、褐铁矿化、黄铁矿化、弱磁铁矿化 表 2 车渡金矿岩石样品主量、微量和稀土元素含量
Table 2. Major, trace and rare earth elements of samples in the Chedu gold deposit
样品号 SiO2 Al2O3 TFe2O3 K2O Na2O MgO MnO CaO TiO2 P2O5 SO3 烧失量 Ba Hf Nb Rb Sr Ta Th U Zr Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu CD301-1 45.17 13.27 14.98 0.31 3.57 3.59 0.19 6.2 3.78 0.4 〈0.01 8.06 138 3.62 2.84 8.32 21 0.15 0.7 0.23 33.4 13.4 7.78 17 2.67 10.1 2.8 0.62 2.45 0.4 2.85 0.49 1.45 0.19 1.74 0.27 CD301-5 48.15 13.77 11.34 0.26 4.04 5.51 0.21 6.62 1.01 0.08 0.5 8.16 61.1 1.87 1.03 3.73 22.3 0.1 0.25 0.23 13.9 12.6 4.91 9.66 1.62 5.6 1.75 0.36 1.57 0.26 2.15 0.41 1.31 0.19 1.75 0.28 CD1-7 84.97 1.95 4.86 0.25 0.24 0.56 0.21 3.52 0.13 0.03 < 0.01 3.4 83.3 13.2 23 5.34 111 1.04 1.18 0.49 214 30.9 20.7 46.8 6.65 31.6 8.15 2.52 8 1.37 7.74 1.42 3.72 0.46 2.64 0.36 CD1-1 53.41 0.9 41.99 0.16 0.01 0.24 0.57 0.69 0.03 0.41 < 0.01 0.93 28.8 2.41 4.99 8.28 46.6 0.36 0.28 0.26 54.1 17.9 3.9 9.2 1.46 7.83 2.56 0.83 2.91 0.61 3.97 0.82 2.47 0.34 2.13 0.3 注:CD301-1、CD301-5为玄武质火山凝灰岩样品,CD1-7、CD1-1为磁铁石英岩金矿石样品。主量元素含量单位为%,微量和稀土元素含量单位为10-6 表 3 车渡金矿磁铁石英岩中石英单矿物氢氧同位素值
Table 3. The hydrogen and oxygen isotope values of quartz single mineral in magnetite quartz rock of the Chedu gold deposit
岩石 单矿物 δD/‰ δ18O石英/‰ 温度/℃ δ18O水‰ 磁铁石英岩 石英 -112.6 16.6 396 12.45 磁铁石英岩 石英 -103.5 16.4 400 12.34 注:δ18O水=δ18O石英-1000lnαQ-W, 1000lnαQ-W =3.38×106T-2-3.4[18] -
[1] 李新生, 牛卯胜, 张崇.碧口地块北缘大型韧性剪切带的构造、成矿意义[J].甘肃地质学报, 2004, (1):54-60. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gsdzxb200401006
[2] 许晨光, 颜丹平, 古术航, 等.扬子板块西北缘碧口地块中-新生代变质、变形与年代限定[J].地学前缘, 2018, 25(1):80-94. http://www.cnki.com.cn/Article/CJFDTotal-DXQY201801007.htm
[3] 展朝毅.西秦岭碧口群主要地质特征、典型矿床与找矿方向[J].中国科技信息, 2010, (17):30-33. http://d.old.wanfangdata.com.cn/Periodical/zgkjxx201017009
[4] 吴杰, 刘家军, 李静贤, 等.南秦岭铧厂沟碧口群玄武岩LA-ICPMS锆石U-Pb年龄及岩石成因研究[J].中国地质, 2014, 41(4):1341-1355. doi: 10.3969/j.issn.1000-3657.2014.04.024
[5] 闫全人, 王宗起, Hanson A D.等.扬子板块西北缘碧口群火山岩系的SHRIMP年代、Sr-Nd-Pb同位素特征及意义[J].地质学报, 2003(4):590. http://d.old.wanfangdata.com.cn/Periodical/dizhixb200304023
[6] 平先权, 郑建平, 熊庆, 等.扬子西北缘碧口块体花岗质岩体锆石U-Pb年龄、Hf同位素特征及其地质意义[J].吉林大学学报(地球科学版), 2014, 44(4):1200-1218. http://d.old.wanfangdata.com.cn/Periodical/cckjdxxb201404013
[7] 徐学义, 陈隽璐, 李向民, 等.扬子地台北缘白勉峡组和三湾组火山岩形成构造环境及岩石成因的地球化学约束[J].地质学报, 2009, 83(11):1703-1718. doi: 10.3321/j.issn:0001-5717.2009.11.013
[8] 廖时理, 陈守余, 张利亚, 等.陕西青木川-苍社地区韧性剪切带型金矿床地球化学特征及地质意义[J].中南大学学报(自然科学版), 2015, 46(3):1082-1093. http://www.cqvip.com/QK/90745B/201503/664714390.html
[9] 邹公明, 李良, 李世金, 等.陕西小燕子沟金矿床流体包裹体特征及成矿物理化学条件研究[J].黄金, 2013, 34(3):22-26. http://d.old.wanfangdata.com.cn/Periodical/huangj201303006
[10] 颜崇高, 李方周, 宋志勇.宁强县小燕子沟金矿地质特征及成矿条件浅析[J].陕西地质, 2012, 30(2):1-11. doi: 10.3969/j.issn.1001-6996.2012.02.001
[11] 张孝攀, 王权锋, 陈聆, 等.陕西省金厂沟金矿床地质及地球化学特征[J].贵金属, 2015, 36(1):29-35. doi: 10.3969/j.issn.1004-0676.2015.01.009
[12] 张利亚, 陈守余, 廖时理.陕西勉略宁地区旧房梁金矿床元素地球化学特征及成矿意义[J].地质科技情报, 2017, 36(2):151-159. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dzkjqb201702020
[13] Sun S S, McDonough W F. Chemical and isotopic systematics in ocean basalt: Implication for mantle composition and processes[C]//Saunders A D, Norry M J. Magmatism in the Ocean Basins. Geological Society of London Special Publications, 1989, 42: 313-345.
[14] 郭林楠, 黄春梅, 张良, 等.胶东罗山金矿床成矿流体来源:蚀变岩型和石英脉型矿石载金黄铁矿稀土与微量元素特征约束[J].现代地质, 2019, 33(1):121-136. http://d.old.wanfangdata.com.cn/Periodical/xddz201901012
[15] Nadoll P, Angerer T, Mauk J L, et al. The chemistry of hydrothermal magnetite:A review[J]. Ore Geology Reviews, 2014, 61:1-32. doi: 10.1016/j.oregeorev.2013.12.013
[16] Dupuis C, Beaudoin G. Discriminant diagrams for iron oxide trace element fingerprinting of deposit types[J].Mineralium Deposita, 2011, 46(4):319-335. doi: 10.1007/s00126-011-0334-y
[17] 陈光远, 黎美华, 汪雪芳, 等.弓长岭铁矿成因矿物学专辑第二章磁铁矿[J].矿物岩石, 1984, 4(2):14-41. http://www.cnki.com.cn/Article/CJFDTotal-KWYS198402004.htm
[18] Clayton R N O, Neil J R, Mayeda T K. Oxygen isotope exchange between quartz and water[J]. Journal of Geophysical Research, 1972, 77:3057-3067. doi: 10.1029/JB077i017p03057
[19] 代堰锫, 张连昌, 王长乐, 等.辽宁本溪歪头山条带状铁矿的成因类型、形成时代及构造背景[J].岩石学报, 2012, 28(11):3574-3594. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201211011
[20] 杨秀清, 李厚民, 李立兴, 等.辽宁鞍山-本溪地区铁矿床流体包裹体和硫、氢、氧同位素特征研究[J].地质学报, 2014, 88(10):1917-1931. http://www.cnki.com.cn/Article/CJFDTotal-DZXE201410011.htm
[21] 李延河, 侯可军, 万德芳, 等.Algoma型和Superior型硅铁建造地球化学对比研究[J].岩石学报, 2012, 28(11):3513-3519. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201211006
[22] 李延河, 侯可军, 万德芳, 等.前寒武纪条带状硅铁建造的形成机制与地球早期的大气和海洋[J].地质学报, 2010, 84(9):1359-1373. http://d.old.wanfangdata.com.cn/Periodical/dizhixb201009010
[23] 史红云, 银剑钊.金矿床中的金矿物、载金矿物及金赋存状态的研究概况[J].黄金科学技术, 1994, (1):21-25. http://www.cqvip.com/Main/Detail.aspx?id=1387596
[24] 高振敏, 杨竹森, 李红阳, 等.黄铁矿载金的原因和特征[J].高校地质学报, 2000, (2):156-162. doi: 10.3969/j.issn.1006-7493.2000.02.007
[25] Large R R, Thomas H, Craw D, et al. Diagenetic pyrite as a source of metals in orogenic gold deposits, OtagoS chist, New Zealand[J].Geology and Geophysics, 2012, 55:137-149. doi: 10.1080/00288306.2012.682282
[26] Thomas H V, Large R R, Bull S W, et al. Pvrite and pyrrhotite textures and compositionin sedimentary rocks, laminated quartz veins, and reefs at tlie Bendigo mine, Australia:Insights for ore genesis[J]. Econ. Geol., 2011, 106:1-31. doi: 10.2113/econgeo.106.1.1
[27] 陈翠华, 张燕, 顾雪祥, 等.贵州苗龙金矿床毒砂中金的赋存状态研究[J].矿床地质, 2013, 32(5):932-940. doi: 10.3969/j.issn.0258-7106.2013.05.005
[28] Martins B S, Lobato L M, Rosière C A. The Archean BIF-hosted Lamego gold deposit, Riodas Velhas greenstone belt, Quadrilátero Ferrífero:Evidence for Cambrian structural modification of an Archean orogenic gold deposit[J].Ore Geology Reviews, 2016, 1(72):963-988.
[29] 杨东潮, 白德胜, 曹琼.坦桑尼亚太古宙绿岩带中BIF型金矿床的勘查标志——以Maheiga金矿床为例[J].黄金科学技术, 2013, 21(4):1-8. doi: 10.3969/j.issn.1005-2518.2013.04.001
[30] 张连昌, 翟明国, 万渝生, 等.华北克拉通前寒武纪BIF铁矿研究:进展与问题[J].岩石学报, 2012, 28(11):3431-3445. http://d.old.wanfangdata.com.cn/Conference/7895390
[31] 代堰锫, 张连昌, 朱明田, 等.鞍山陈台沟BIF铁矿与太古代地壳增生:锆石U-Pb年龄与Hf同位素约束[J].岩石学报, 2013, 29(7):2537-2550. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201307019
[32] 陈柏林, 董法先, 李中坚.韧性剪切带型金矿成矿模式[J].地质论评, 1999, (2):186-192. doi: 10.3321/j.issn:0371-5736.1999.02.012
[33] 陈柏林, 吴淦国, 刘晓春, 等.北山地区发现韧性剪切带型金矿床[J].中国区域地质, 2000, (3):336. doi: 10.3969/j.issn.1671-2552.2000.03.020
-