Material Composition and Geological Significance of the Newly Discovered Wangzhuang Gold Deposit in South Qinling
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摘要:
王庄金矿是2021年南秦岭地区找矿新发现的矿床,矿床类型为微细浸染型,矿体受构造和地层双重控制,呈层间破碎带产出。王庄金矿床矿石矿物主要为毒砂、黄铁矿,通过镜下鉴定及电子探针分析,金主要以不可见金存于毒砂、含砷黄铁矿中,未见自然金。结合野外工作,根据矿物共生组合及其交生关系可将王庄金矿床划分为4个成矿阶段:I.黄铁矿、石英脉成矿早阶段;II.毒砂、黄铁矿、石英脉成矿主阶段;III.石英脉伴少量多金属硫化物阶段;IV.碳酸盐岩晚阶段。不同阶段的黄铁矿具有不同的微量元素特征:I阶段黄铁矿贫As、Au,富Fe、S;II、III阶段黄铁矿具高As、Au,低S、Fe特征,且此阶段黄铁矿当中Au、As存在一定的正相关关系。王庄金矿矿石中黄铁矿Co/Ni均值为2.03,中位数为1.34,指示成矿主阶段形成的黄铁矿有岩浆流体的加入。且在Co/Ni<1及1.2<Co/Ni<2.5范围内存在两个含金集中区,表明可能存在两种不同流体的成矿作用。综合矿床地质及矿物组构特征初步认为,王庄金矿床存在多阶段的成矿作用。
Abstract:The Wangzhuang gold deposit is a newly discovered deposit in South Qinling in 2021. The ore type is a fine disseminated type. The ore body is controlled by both structure and stratum, and it is produced in an interlayer fracture zone. The main metallic minerals of the Wangzhuang gold deposit are arsenopyrite and pyrite, According to microscopic identification and electron probe analysis, the gold is mainly invisible gold in arsenopyrite and arsenian pyrite, and no natural gold is found. Based on the field work, the Wangzhuang gold deposit can be divided into four ore-forming stages: I, the early ore-forming-stage of pyrite quartz veins; II, the main stage of arsenopyrite, pyrite, and quartz veins; III, quartz veins with a small amount of polymetallic sulfide stage; IV, late carbonate stage. The pyrite in different stages has different characteristics of trace elements: stage I pyrite is poor in As and Au, rich in Fe and S; the pyrite of stage II and III are characterized by high As, Au, low S and Fe, and there is a positive correlation between Au and As in pyrite of this stage. The average Co/Ni ratio of pyrite in the Wangzhuang gold deposit is 2.03 and the median is 1.34, indicating that pyrite formed in the ore-forming master stage has the addition of magmatic fluid. In addition, there are two gold-bearing areas in the range of Co/Ni < 1 and 1.2 < Co/Ni < 2.5, indicating that there may be mineralization of two different fluids. Based on the geological and mineral fabric characteristics of the deposit, it is preliminarily concluded that there is multi-stage mineralization in the Wangzhuang gold deposit.
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Keywords:
- the Wangzhuang gold deposit /
- material composition /
- pyrite /
- the South Qinling
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研究区南临祁连造山带,北接中亚造山带,其所处构造环境的特殊性对区域构造演化及板块运动有着重大意义。该地区岩浆演化期次及构造背景研究较为薄弱且存在较大争议,前人通过对合黎山地区五坝和张家窑岩体锆石U-Pb年代学及同位素地球化学特征研究,其年龄介于432~397 Ma,为中志留世—早泥盆世,认为阿拉善地块西南缘早古生代很可能受控于祁连造山带的构造演化,处于后碰撞拉伸环境(王增振等,2020);通过对龙首山西山头窑地区三期岩体锆石U-Pb年代学研究,其年龄介于304.3~281.2 Ma,为晚石炭世—早二叠世,处于弧后洋盆闭合过程,是古亚洲洋向南俯冲的结果(董国强等,2022);而强利刚等(2019)认为龙首山地壳在晚古生代处于拉伸的稳定阶段。对合黎山地区岩浆岩形成时代及构造环境研究存在重要意义。龙首山成矿带区内侵入岩发育广泛,主要为酸性、中酸性岩石,主要岩性以花岗岩、花岗闪长岩、英云闪长岩等为主(张甲民等,2017),前人对龙首山成矿带的研究工作主要以东段为主,且主要集中在早古生代(牛宇奔等,2018;刘文恒等,2019;王增振等,2020)。而不同构造环境下的侵入岩具有不同的地球化学特征及同位素特征,能有效反映其岩浆源区及构造演化等重要信息。笔者在前人工作基础上对该区花岗闪长岩开展了锆石U-Pb年代学、岩石地球化学及Lu-Hf同位素特征的研究,确定该岩体形成时代并探讨这些黑云母花岗闪长岩的成因问题及龙首山成矿带西南缘构造环境特征。
1. 区域地质概况
合黎山地处阿拉善地块龙首山成矿带西南缘,大地构造位置属于华北板块西南边缘(图1a)(谭文娟等,2012),北以龙首山北缘断裂与潮水中新生代断陷相邻(汤中立等,1999),南以南缘断裂与走廊过渡带分开。区内成矿条件有利(焦建刚等,2007)。龙首山成矿带是中国西北重要的铀成矿带(王承花,2010),同时中国著名的金川镍矿也位于该成矿带内(强利刚等,2019;张照伟等,2023)。
区内地质构造复杂,次级构造发育,逆冲构造及伸展构造叠加,总体构造为NWW向(甘肃省地质局,1974),出露地层包括前震旦系龙首山群的角闪岩相–绿片岩相变质岩等中级区域变质岩系,其与上覆地层均为不整合接触;震旦系下统及中上统的云母石英片岩、变粒岩及变质砂岩、大理岩等为主的浅变质岩,其下统与中—上统之间多为断层接触;侏罗系青土井群的砂岩、砂砾岩等为主的陆源碎屑岩夹煤层,其与上覆地层及下伏地层均为不整合接触;白垩系以砂砾岩、泥岩等为主的碎屑岩;第三系以砾岩、含砾砂岩为主的沉积岩及第四系松散堆积物(图1b)。
测区内岩浆岩发育广泛,主要为酸性、中酸性岩石为主,侵入活动主要是在加里东中期及华力西期,以华力西期侵入岩最为发育,主要岩性以花岗岩、花岗闪长岩、英云闪长岩等为主,其中以花岗闪长岩出露最为广泛,其次为英云闪长岩。罗城岩体主要为花岗闪长岩发育,其中可见花岗岩、闪长岩呈脉状发育。区内五坝和张家窑岩体锆石U-Pb年代学年龄介于432~397 Ma,为中志留世—早泥盆世(王增振等,2020);西山头窑地区岩体锆石U-Pb年代学年龄介于304.3~281.2 Ma,为晚石炭世—早二叠世。
2. 样品采集及岩石学特征
罗城岩体主要位于甘肃省高台县罗城镇北侧,其岩性主要为黑云母花岗闪长岩,野外岩体出露较为完整,笔者选取了合黎山地区高台县罗城幅的黑云母花岗闪长岩进行锆石U-Pb定年分析,共采集样品5件,其中岩石年龄同位素样品1件,并在岩石年龄同位素样品采集处配套采集岩石地球化学样品4件。样品采集地理坐标:E 99°43′39″,N 39°46′30″和E 99°41′43″,N 39°48′20″。为确保锆石数据准确性,样品均为未风化蚀变的新鲜岩石。
岩石新鲜面为灰白色,具半自形粒状结构,块状构造(图2a)。主要矿物及含量:斜长石(45%),石英(20%),碱性长石(15%),普通角闪石(15%),黑云母(5%)。斜长石粒径约0.30~1.30 mm,呈半形粒状、板状,具聚片双晶,表面浑浊,微裂隙发育,次生绢云母化,均匀分布。碱性长石粒径约0.20~1.10,呈半自形板状,具卡式双晶,少量分布。石英粒径约0.10~2.00 mm,呈他形粒状,波状消光,沿长石粒间分布。普通角闪石粒径约0.20~1.60 mm,呈他形柱状,黄褐色,截面呈菱面体状,具角闪石式解理,绿泥石化,沿长英质粒间定向分布。黑云母粒径约0.15~2.25 mm,呈鳞片状、片状,褐黄色-红褐色,沿长英质粒间定向分布。副矿物有磷灰石、绿帘石(图2b、图2c、图2d)。
3. 样品分析方法
样品的锆石挑选、制靶、CL照相由西安瑞石地质科技有限公司完成,采用标准重矿物分离技术分选出重矿物,随后在双目镜下挑选出锆石颗粒,将不同特征的锆石颗粒粘在双面胶上,并用无色透明的环氧树脂固定,待其固化之后将表面抛光至锆石内部暴露。然后拍摄阴极发光图像、透射光图像和反射光图像,选取分析点位。
锆石U-Pb定年和Hf同位素组成分析在中国地质调查局西安地质调查中心岩浆作用成矿与找矿重点实验室完成。锆石U-Pb定年在LA-ICP-MS仪器上用标准测定程序进行,样品采用激光剥蚀等离子体质谱仪原位分析锆石微区的铀铅比值(206Pb/238U、207Pb/235U和207Pb/206Pb)(李艳广等,2015)并通过Glitter计算程序计算锆石的年龄及标准偏差;应用Isoplot(Ludwig, 2003)计算程序对锆石样品的206Pb/238U年龄和207Pb/235U年龄在谐和图上进行投图,并计算谐和年龄测点的加权平均值。
锆石Hf同位素组成运用Neptune型多接收电感耦合等离子体质谱仪和GeolasPro型激光剥蚀系统联用的方法完成(袁洪林等,2007),所选测试位置均与锆石U-Pb测点位置相近,测试束斑直径为32 μm,采用国际标准锆石91500进行监控和样品外部校正。
主量元素和微量元素分析测试在中国地质调查局西安矿产资源调查中心完成,主量元素采用X荧光光谱仪进行分析,稀土和微量元素采用等离子质谱仪进行分析,测试结果见表1。
表 1 罗城黑云母花岗闪长岩主量元素(%)、微量元素(10−6)、稀土元素(10−6)分析结果表Table 1. Analysis results of major elements (%), trace elements (10−6) and rare earth elements (10−6) in Luocheng biotite granodiorite样品编号 LCYT03 LCYT04 LCYT05 LCYT06 SiO2 59.84 58.75 58.52 59.09 Al2O3 16.91 17.25 17.28 17.28 Fe2O3 7.13 7.82 7.55 7.61 CaO 6.33 6.70 6.93 6.68 MgO 3.13 3.38 3.53 3.34 K2O 1.87 1.49 1.49 1.54 Na2O 2.52 2.60 2.55 2.60 P2O5 0.13 0.15 0.15 0.15 TiO2 0.68 0.74 0.77 0.75 MnO 0.13 0.14 0.14 0.14 LOI 1.03 0.74 0.85 0.60 总和 99.70 99.76 99.75 99.79 K2O+Na2O 4.40 4.09 4.04 4.15 K2O/Na2O 0.74 0.57 0.59 0.59 δ 1.15 1.06 1.05 1.07 A/NK 2.74 2.93 2.98 2.9 A/CNK 0.97 0.97 0.96 0.97 Rb 61.1 49.2 40.6 46.9 Th 3.37 4.58 5.70 8.46 U 0.79 0.72 0.74 0.75 Nb 4.48 4.76 4.64 4.64 Sr 376 429 413 403 Zr 84.3 112 88.6 118 Hf 2.34 2.79 2.23 2.97 F 454 320 663 360 Sn <1.80 <1.80 <1.80 <1.80 Cr 12.9 17.6 14.1 14.1 Li 16.8 18.3 17.3 17.4 Be 0.76 0.87 0.86 0.79 V 166 186 180 174 Co 15.3 16.2 15.6 15.3 Ni 8.36 10.9 11.2 10.4 Ga 16.6 17.7 16.3 16.4 Cs 2.52 2.92 2.69 3.15 Ta 0.33 0.35 0.34 0.35 W 2.30 1.91 1.81 1.80 Bi 0.073 0.070 <0.050 0.057 La 12.0 14.3 12.5 12.5 Ce 27.1 28.9 25.5 25.7 Pr 3.60 3.59 3.32 3.21 Nd 16.4 15.3 14.6 14.1 Sm 3.91 3.37 3.28 3.14 Eu 1.05 1.07 1.05 1.03 Gd 4.14 3.54 3.49 3.41 Tb 0.66 0.55 0.54 0.52 Dy 4.04 3.28 3.24 3.15 Ho 0.83 0.68 0.67 0.65 Er 2.54 2.03 2.02 1.95 Tm 0.36 0.29 0.29 0.28 Yb 2.33 1.88 1.87 1.84 Lu 0.36 0.30 0.30 0.29 Y 21.3 17.2 16.9 16.4 ΣREE 79.32 79.08 72.67 71.77 LREE 64.06 66.53 60.25 59.68 HREE 15.26 12.55 12.42 12.09 LREE/HREE 4.20 5.30 4.85 4.94 (La/Yb)N 3.69 5.46 4.79 4.87 δEu 0.80 0.95 0.95 0.96 δCe 1.01 0.99 0.97 0.99 4. 分析结果
4.1 锆石U-Pb定年分析
样品的锆石颗粒的CL图像(图3)显示所选的锆石为透明的自形晶体,为无色透明或浅黄色,大部分锆石结晶较好,短柱状晶形,阴极发光电子图像特征均显示出典型的岩浆结晶韵律环带结构。
本次所选锆石样品25颗,均为有效样品,黑云母花岗闪长岩锆石U-Pb分析测试结果见表2,锆石Th含量为34.81×10−6~129.66×10−6,U含量为52.88×10−6~147.36×10−6,Th/U值为0.55~0.97,均大于0.4,说明锆石为岩浆成因(吴元保等,2004)。锆石微量元素测试结果见表3,其显示出重稀土富集,相对亏损轻稀土元素的特征,显示典型的岩浆锆石成因特征(Hoskin,2000)。锆石谐和图反映出锆石U-Pb年龄数据分布比较集中且谐和程度较好(图4a),所有数据协和度均符合要求,证明数据均有效。通过数据分析得到206Pb/238U加权平均年龄为(289±3)Ma,(MSWD=0.57),代表岩浆结晶年龄(图4b)。
表 2 罗城花岗闪长岩(LCYT01)锆石LA-ICP-MS测年结果Table 2. Zircon LA-ICP-MS dating results of Luocheng granodiorite (LCYT01)测点号 含量(10−6) Th/U 同位素比值 同位素年龄 Pb Th U 207Pb/206Pb ±1δ 207Pb/235U ±1δ 206Pb/238U ±1δ 208Pb/232Th ±1δ 207Pb/206Pb ±1δ 207Pb/235U ±1δ 206Pb/238U ±1δ 208Pb/232Th ±1δ LCYT001 15.96 79.28 81.67 0.97 0.05153 0.00423 0.32079 0.02551 0.04511 0.00102 0.01452 0.00048 264.4 177.81 282.5 19.61 284.5 6.28 291.3 9.56 LCYT002 14.25 47.28 72.22 0.65 0.05202 0.0046 0.32939 0.02827 0.04589 0.00108 0.01269 0.00063 286.1 189.7 289.1 21.59 289.2 6.68 255 12.64 LCYT003 12.04 34.81 63.55 0.55 0.0524 0.00697 0.32463 0.04227 0.0449 0.00134 0.01375 0.00088 302.7 277.82 285.5 32.4 283.2 8.26 276.1 17.48 LCYT004 19.92 93.99 98.06 0.96 0.04923 0.00498 0.31772 0.03138 0.04678 0.00114 0.01432 0.00059 158.7 220.85 280.1 24.18 294.7 7.05 287.5 11.7 LCYT005 11.37 41.91 57.97 0.72 0.0517 0.00762 0.33365 0.04817 0.04678 0.00152 0.01611 0.00095 272.2 306.78 292.4 36.67 294.7 9.39 323 18.95 LCYT006 16.79 80.92 85.36 0.95 0.05021 0.00438 0.31261 0.02651 0.04513 0.00103 0.01345 0.00049 204.9 190.68 276.2 20.51 284.6 6.35 270 9.73 LCYT007 27.09 129.66 147.36 0.88 0.05412 0.00356 0.342 0.0216 0.04582 0.00096 0.01384 0.00042 375.8 141.54 298.7 16.34 288.8 5.93 277.8 8.4 LCYT008 12.51 45.55 65.96 0.69 0.05029 0.0043 0.32015 0.0266 0.04616 0.00106 0.01535 0.00062 208.3 187.16 282 20.46 290.9 6.51 307.8 12.31 LCYT009 13.69 45.68 72.34 0.63 0.05153 0.00444 0.33081 0.02763 0.04656 0.00109 0.01519 0.00068 264.4 186.14 290.2 21.08 293.3 6.73 304.7 13.59 LCYT010 12.68 46.02 66.65 0.69 0.05115 0.00472 0.33038 0.0297 0.04685 0.00111 0.01457 0.00063 247.4 199.46 289.9 22.67 295.1 6.83 292.5 12.53 LCYT011 13.09 49.92 68.97 0.72 0.04792 0.00563 0.30937 0.03563 0.04682 0.00122 0.01473 0.00087 94.2 257.92 273.7 27.63 295 7.49 295.6 17.3 LCYT012 12.53 47.8 65.53 0.73 0.0521 0.00482 0.33683 0.03033 0.04689 0.00112 0.01606 0.00063 289.7 198 294.8 23.04 295.4 6.87 322 12.57 LCYT013 18.31 92.71 98.11 0.94 0.05178 0.0039 0.32956 0.02399 0.04618 0.001 0.01362 0.00044 275.6 163.56 289.2 18.32 291 6.19 273.3 8.78 LCYT014 19 93.38 105.35 0.89 0.05329 0.00398 0.3273 0.02358 0.04457 0.00099 0.01433 0.00046 340.9 160.32 287.5 18.04 281.1 6.09 287.6 9.21 LCYT015 15.16 51.53 80.72 0.64 0.04948 0.00412 0.30521 0.02472 0.04476 0.00098 0.01424 0.00055 170.8 183.56 270.5 19.23 282.3 6.06 285.7 11.06 LCYT016 14.01 55.43 76.33 0.73 0.0503 0.00537 0.30848 0.03208 0.04451 0.00118 0.01286 0.00065 209 229.96 273 24.9 280.7 7.27 258.2 12.91 LCYT017 11.3 45.88 60.72 0.76 0.05239 0.00499 0.33231 0.03079 0.04604 0.00115 0.01288 0.0006 302.4 203.45 291.3 23.47 290.1 7.1 258.6 11.9 LCYT018 16.38 73.42 88.24 0.83 0.05321 0.0037 0.3292 0.02201 0.0449 0.00096 0.01409 0.00044 337.7 149.52 289 16.81 283.2 5.92 282.7 8.81 LCYT019 15.81 76.58 80.92 0.95 0.05166 0.00378 0.32813 0.02317 0.0461 0.00099 0.01466 0.00044 270.4 159.18 288.1 17.72 290.6 6.07 294.2 8.75 LCYT020 13.2 53.42 68.41 0.78 0.05023 0.00423 0.31534 0.02582 0.04557 0.00103 0.0151 0.00054 205.7 184.61 278.3 19.93 287.3 6.36 302.9 10.68 LCYT021 10.77 36.85 52.88 0.70 0.05095 0.0044 0.32225 0.02702 0.04592 0.00105 0.01367 0.00064 238.6 187.4 283.6 20.75 289.4 6.46 274.3 12.67 LCYT022 13.95 47.61 68.78 0.69 0.05283 0.00388 0.34372 0.02436 0.04724 0.00102 0.01389 0.00055 321.3 157.94 300 18.41 297.6 6.25 278.8 10.94 LCYT023 23.03 103.73 117.27 0.88 0.05235 0.00313 0.33694 0.01926 0.04673 0.00094 0.01421 0.00041 300.6 130.55 294.9 14.63 294.4 5.77 285.2 8.1 LCYT024 16.81 56.88 85.69 0.66 0.05387 0.00347 0.34195 0.02113 0.04609 0.00095 0.01337 0.00048 365.6 138.52 298.6 15.99 290.5 5.83 268.4 9.65 LCYT025 14.8 67.05 76.38 0.88 0.05203 0.00384 0.33011 0.02359 0.04608 0.00099 0.01419 0.00047 286.8 160.34 289.7 18 290.4 6.11 284.8 9.33 表 3 罗城花岗闪长岩锆石分析点位微量元素(10−6)测试结果Table 3. Test results of trace elements (10−6) at zircon analysis points of Luocheng granodiorite测点号 Nb La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Ta LCYT001 1.10 0.06 8.23 0.05 0.23 0.49 1.28 27.74 0.78 107.27 40.27 181.12 35.88 339.17 66.63 0.28 LCYT002 0.49 0.04 6.69 0.03 2.07 3.33 0.40 11.13 8.82 67.14 26.56 126.02 27.32 290.78 57.98 0.24 LCYT003 0.61 0.00 6.26 0.02 0.49 2.64 0.29 7.43 4.65 45.16 17.35 87.13 19.02 192.36 38.24 0.27 LCYT004 0.63 0.06 9.25 0.08 0.44 0.69 1.15 25.90 3.00 112.88 44.64 196.44 39.56 377.09 71.61 0.26 LCYT005 0.55 0.00 6.42 0.03 1.79 4.98 0.36 8.45 9.99 40.51 19.27 87.53 19.76 189.52 37.30 0.23 LCYT006 0.52 0.01 9.03 0.05 0.63 1.34 0.91 24.92 3.67 102.58 38.80 175.98 35.30 323.64 65.73 0.28 LCYT007 0.46 0.02 17.04 0.11 1.55 2.65 0.85 24.04 6.96 113.49 45.17 206.58 43.34 418.84 82.25 0.41 LCYT008 1.37 0.00 7.31 0.03 1.49 3.08 0.46 10.50 8.69 50.85 20.86 97.32 21.63 218.50 42.57 0.30 LCYT009 0.53 0.04 7.76 0.02 0.67 1.58 0.24 7.99 4.06 43.08 18.56 85.81 19.58 193.52 36.74 0.31 LCYT010 0.65 0.00 7.39 0.03 0.40 1.28 0.24 11.38 3.43 52.67 20.97 98.21 22.28 213.94 42.28 0.26 LCYT011 0.67 0.01 7.65 0.05 0.44 2.14 0.43 11.65 4.08 54.24 22.14 101.02 21.59 221.82 41.65 0.21 LCYT012 0.58 0.24 7.21 0.07 0.73 1.88 0.48 9.62 4.43 51.70 20.95 100.70 22.19 222.33 43.83 0.39 LCYT013 3.01 0.01 9.21 0.08 1.56 2.82 0.95 24.93 3.94 113.56 45.37 198.15 41.36 399.32 71.97 0.38 LCYT014 0.66 0.01 9.65 0.07 1.79 3.63 1.15 28.87 9.60 117.65 44.48 198.85 41.00 392.05 76.11 0.34 LCYT015 0.58 0.00 8.44 0.02 2.16 4.68 0.33 10.50 9.83 52.88 20.95 100.98 22.47 230.32 44.42 0.31 LCYT016 0.74 0.00 7.73 0.04 0.49 1.29 0.40 12.46 4.08 61.43 26.20 120.97 26.57 261.96 52.64 0.38 LCYT017 0.73 0.00 6.93 0.02 0.87 2.13 0.43 12.06 5.04 54.07 23.41 106.05 23.33 232.88 44.25 0.33 LCYT018 0.84 0.01 8.09 0.06 0.57 1.82 0.83 20.89 4.58 92.58 36.57 172.39 35.31 347.52 67.40 0.29 LCYT019 0.61 0.00 8.04 0.06 1.53 3.32 0.97 26.28 7.25 103.33 41.09 175.93 36.48 349.56 66.29 0.23 LCYT020 0.47 0.00 7.31 0.02 1.72 5.06 0.39 14.22 8.78 63.23 24.83 115.49 25.21 238.91 45.30 0.22 LCYT021 0.57 0.01 5.70 0.02 0.69 1.87 0.53 10.94 5.15 53.16 21.38 104.62 22.91 221.56 45.69 0.30 LCYT022 0.53 0.04 6.60 0.03 0.27 1.73 0.46 12.33 3.89 67.24 25.79 122.86 27.12 273.00 52.93 0.28 LCYT023 0.70 0.04 9.56 0.09 0.57 1.92 1.18 27.41 5.00 122.96 49.00 227.37 46.39 456.07 89.13 0.38 LCYT024 1.14 0.04 8.63 0.02 1.85 4.19 0.28 9.30 10.49 48.68 20.06 95.23 20.74 214.10 41.88 0.34 LCYT025 1.12 0.02 7.63 0.07 1.41 2.91 1.04 22.23 4.01 93.47 36.23 160.65 34.00 327.88 65.05 0.25 4.2 锆石Hf同位素特征
在LA-ICP-MS锆石U-Pb测年的基础上,对黑云母花岗闪长岩样品25颗锆石测点进行了锆石微区Hf同位素测定。测点的数据分析结果(表4)。176Yb/177Hf值介于
0.012222351 ~0.042050552 ,176Lu/177Hf值介于0.00042471 ~0.001378472 ,均小于0.002,说明锆石在形成后具有很少的放射成因Hf的积累。因此,锆石 176Hf/177Hf值可能代表该锆石形成时的176Hf/177Hf值(吴福元等,2007),176Hf/177Hf值介于0.282726048 ~0.282787588 ,εHf(t)值均为正值,介于+4.37~+6.88,平均为+5.6,通过锆石Hf同位素εHf(t)-U-Pb年龄t(Ma)图解(图5a),测点均落在球粒陨石–亏损地幔之间,反映其源区为年轻的幔源组分或新生地壳,Hf同位素一阶段模式年龄T(DM1)分布范围为615.4~703.0 Ma,平均值为660.5 Ma,地壳模式年龄T(DMC)分布范围为808.6~952.5 Ma,平均值为882.8 Ma,地壳模式年龄T(DMC)较集中(图5b)。表 4 黑云母花岗闪长岩锆石Hf同位素分析结果Table 4. Zircon Hf isotope analysis results of biotite granodiorite分析点 t(Ma) 176Yb/177Hf 176Lu/177Hf 176Hf/177Hf ±2σ Hfi εHf (0) εHf (t) ±1σ T(DM1) T(DMC) ±1σ fLu/Hf LCYT01-01 284.5 0.018558653 0.000625497 0.282772262 0.0000194150 0.282769 0.079994272 6.14162 0.679525 634.4 846.8 0.06673 - 0.9583 LCYT01-02 289.2 0.021350813 0.00072988 0.282742229 0.0000173343 0.282738 - 0.982120012 5.16050 0.606701 676.8 910.5 0.065471 - 0.95134 LCYT01-03 283.2 0.018541903 0.0006332 0.282761526 0.0000162177 0.282758 - 0.299686693 5.73214 0.56762 649.0 871.0 0.062774 - 0.95779 LCYT01-04 294.7 0.022088228 0.000738473 0.282787588 0.0000174089 0.282784 0.621999168 6.88254 0.609311 615.4 808.6 0.063449 - 0.95077 LCYT01-05 294.7 0.016473205 0.000610408 0.282734375 0.0000178101 0.282731 - 1.259864349 5.02445 0.623354 685.4 922.9 0.066228 - 0.95931 LCYT01-06 284.6 0.03087808 0.00103004 0.282748701 0.0000169380 0.282743 - 0.753226632 5.23386 0.59283 673.2 902.5 0.065308 - 0.93133 LCYT01-07 288.8 0.019725731 0.000669661 0.282759209 0.0000166409 0.282756 - 0.381620593 5.76427 0.582432 652.8 873.1 0.063558 - 0.95536 LCYT01-08 290.9 0.025750031 0.000867335 0.282742988 0.0000180678 0.282738 - 0.955258813 5.19757 0.632374 678.1 909.3 0.066791 - 0.94218 LCYT01-09 293.3 0.021818077 0.00074069 0.282752659 0.0000170188 0.282749 - 0.61326993 5.61588 0.595659 662.8 885.4 0.06456 - 0.95062 LCYT01-10 295.1 0.031810315 0.001072333 0.282760072 0.0000185273 0.282754 - 0.35109486 5.85224 0.648455 658.3 872.0 0.067113 - 0.92851 LCYT01-11 295 0.032320695 0.00106083 0.282770029 0.0000187588 0.282764 0.001027859 6.20471 0.656558 644.5 850.3 0.066935 - 0.92928 LCYT01-12 295.4 0.025753941 0.00084072 0.282744619 0.0000195056 0.28274 - 0.897570925 5.35710 0.682698 675.5 902.8 0.068675 - 0.94395 LCYT01-13 291 0.042050552 0.001378472 0.282744602 0.0000188351 0.282737 - 0.898174811 5.15840 0.659227 684.9 911.5 0.069048 - 0.9081 LCYT01-14 281.1 0.025917388 0.000895112 0.282777258 0.0000173229 0.282773 0.256671065 6.19473 0.606302 631.9 840.9 0.064172 - 0.94033 LCYT01-15 282.3 0.012222351 0.00042471 0.282730661 0.0000185893 0.282728 - 1.391186427 4.65946 0.650625 687.1 936.4 0.06705 - 0.97169 LCYT01-16 280.7 0.026071795 0.00089378 0.282726048 0.0000187777 0.282721 - 1.5543273 4.37430 0.65722 701.7 952.5 0.068661 - 0.94041 LCYT01-17 290.1 0.026377494 0.000892334 0.282753361 0.0000177671 0.282749 - 0.588435111 5.54265 0.621848 664.4 887.5 0.065933 - 0.94051 LCYT01-18 283.2 0.024916918 0.000880457 0.282778938 0.0000203212 0.282774 0.316093287 6.30197 0.711244 629.4 835.9 0.068288 - 0.9413 LCYT01-19 290.6 0.018210323 0.000633771 0.282781801 0.0000175364 0.282778 0.417339793 6.60951 0.613775 621.6 822.4 0.063668 - 0.95775 LCYT01-20 287.3 0.01802085 0.000615423 0.282772775 0.0000170572 0.282769 0.098119936 6.22222 0.597003 633.5 843.9 0.06338 - 0.95897 LCYT01-21 289.4 0.020384277 0.000718113 0.282742372 0.0000184710 0.282738 - 0.9770409 5.17215 0.646485 676.4 909.9 0.067032 - 0.95213 LCYT01-22 297.6 0.02594746 0.000881354 0.282760012 0.0000161587 0.282755 - 0.353235735 5.94105 0.565556 655.2 868.5 0.063322 - 0.94124 LCYT01-23 294.4 0.029427132 0.001014853 0.282726672 0.0000206482 0.282721 - 1.532286504 4.66656 0.722688 703.0 944.4 0.071574 - 0.93234 LCYT01-24 290.5 0.018539508 0.000641115 0.282769911 0.0000162977 0.282766 - 0.003162189 6.18517 0.570421 637.8 848.5 0.062508 - 0.95726 LCYT01-25 290.4 0.021881036 0.000749457 0.282741158 0.0000155788 0.282737 - 1.019970646 5.14473 0.545259 678.6 912.3 0.063102 - 0.95004 图 5 罗城黑云母花岗闪长岩锆石εHf(t)-t(Ma)图解(a)(据李良等,2018)和地壳模式年龄T(DMC)统计直方图(b)Figure 5. (a)Zircon εHf(t)-t (Ma) diagram (According to LI Liang et al., 2018) and (b) crustal model age T (DMC) statistical histogram (b) of Luocheng biotite granodiorite4.3 主量元素特征
合黎山地区罗城黑云母花岗闪长岩的主量元素分析结果见表1,其SiO2含量介于58.52%~59.84%,Al2O3含量介于16.91%~17.28%。全碱含量Na2O+K2O介于4.04%~4.40%,相对富碱,Na2O含量介于2.52%~2.60%,K2O含量介于1.49%~1.87%,富钠贫钾。里特曼指数δ介于1.05~1.15。根据CIPW标准矿物计算(Le Maitre,1979),石英(Qtz)含量介于18.97%~20.69%,碱性长石(A)含量介于11.6%~14.66%,斜长石(Pl)含量介于47.86%~50.76%,在Q-A-P图解中(图6a),处在花岗闪长岩区域中。SiO2-(Na2O+K2O-CaO)图解(图6b)反应岩石属于钙性系列。SiO2-K2O图解(图6c)反映岩石主体属于钙碱性系列。铝饱和指数A/CNK比较集中,介于0.96~0.97,A/NK介于2.74~2.98,在A/CNK-A/NK图解中(图6d),处在准铝质范围内。
图 6 罗城黑云母花岗闪长岩Q-A-P图解(a)(据Streckeisen, 1976)、SiO2-(Na2O+K2O-CaO)图解(b)(据Peccerillo et al., 1976)、SiO2-K2O图解(c)(据Peccerillo et al., 1976)及A/NK-A/CNK图解(d)(据Maniar et al.,1989)Figure 6. (a) Q-A-P diagram of Luocheng biotite granodiorite, (b) SiO2- (Na2O+K2O-CaO) diagram, (c) SiO2-K2O diagram and (d) A/NK-A/CNK diagrams4.4 微量元素特征
合黎山地区罗城黑云母花岗闪长岩的稀土元素分析结果见表1,其稀土元素总量ΣREE在71.77×10−6~79.32×10−6之间,平均为75.71×10−6。LREE/HREE值在4.20~5.30之间,平均为4.82,相对富集轻稀土,亏损重稀土。(La/Yb)N在3.69~5.46之间,平均为4.70,稀土元素球粒陨石标准化配分曲线图(图4a)中显示稀土元素为右倾型配分模式。δEu值在0.80~0.96之间,平均值为0.91,Eu具轻度负异常,说明在岩浆演化过程中有少量的斜长石分离结晶作用。
合黎山地区罗城黑云母花岗闪长岩的微量元素分析结果见表1,在微量元素原始地幔标准化蛛网图(图7b)上可见,岩石均相对富集Rb、Th、K等大离子亲石元素,亏损Nb、Ta、P、Ti等高场强元素。
5. 讨论
5.1 岩体成岩时代及岩石成因
合黎山地区罗城岩体锆石自形程度好,具有典型的岩浆结晶韵律环带结构(图5),且Th/U值均大于0.4,为典型的岩浆锆石(王新雨等,2023;李平等,2024),其锆石数据谐和度较高,206Pb/238U加权平均年龄为(289±3) Ma ,可代表岩浆结晶年龄,因此,合黎山地区罗城岩体形成于早二叠世。
合黎山地区罗城花岗闪长岩Ga含量为16.3×10−6~17.7×10−6,Al2O3含量为16.91%~17.28%,10000Ga/Al值为1.78~1.93,平均为1.84,小于A型花岗岩下限2.6(Whalen et al., 1987),在Zr-10000Ga/Al、Ce-10000Ga/Al、Y-10000Ga/Al图解(图8b、 图8c、图8d)中,罗城岩体均投影在I&S花岗岩区域,在K2O-Na2O图解(图8a)中,罗城岩体均处于I型花岗岩区域。根据岩石主量元素特征可知,罗城花岗闪长岩具有钙碱性、准铝质特征,其A/CNK比较集中,介于0.96~0.97,均小于1.1,与I型花岗岩一致(Chappell et al., 1992;李宏卫等,2021),且P2O5含量与SiO2含量存在负线性关系,与I型花岗岩演化趋势一致(Wolf et al., 1994)。综合判断分析,罗城花岗闪长岩属于结晶分异I型花岗岩。
图 8 罗城黑云母花岗闪长岩K2O-Na2O图解(a)及Zr、Ce、Y-10000Ga图解(b、c、d)(据Whalen et al.,1987)Figure 8. (a) K2O-Na2O and (b, c, d) Zr, Ce, Y-10000 Ga diagram of Luocheng biotite granodiorite5.2 岩浆起源及演化特征
I型花岗岩主要来源于板块边缘陆壳下部,可能与地壳岩石的部分熔融(徐克勤等,1982)、交代岩石圈地幔部分熔融(Jiang et al., 2006)等有关,罗城黑云母花岗闪长岩属于钙碱性系列,富集Rb、Th、K等大离子亲石元素和轻稀土元素,亏损Nb、Ta、P、Ti等高场强元素,指示岩体具有大陆地壳物质的参与,岩石Nb/Ta=13.25~13.65,平均值为13.52,接近大陆地壳Nb/Ta值(=10~14)。在判断源岩的C/MF-A/MF图解(图9a)中,显示岩体源岩可能为基性岩的部分熔融,岩石δEu值具轻度负异常,在0.80~0.96之间,平均值为0.91,说明在岩浆演化过程中有少量的斜长石分离结晶作用,在δEu-(La/Yb)N图解中(图9b),样品投点均落在了壳源与壳幔混合源花岗岩区域,La/Ta值为35.71~40.86,大于起源于岩石圈地幔或受其混染岩浆La/Ta值的下限25,指示其为幔源或者壳幔混合源(Lassiter et al., 1997)。
罗城黑云母花岗闪长岩锆石Hf二阶段模式年龄T(DMC)分布范围为808.6~952.5 Ma,εHf(t)值介于+4.37~+6.88,通过锆石εHf(t)-U-Pb年龄t(Ma)图解(图7a),测点均落在球粒陨石–亏损地幔之间,反映其源区为年轻的幔源组分或具有新生地壳演化趋势(李金超等,2021)。
在野外工作中,在黑云母花岗闪长岩中发现暗色微细粒包体发育(图10),包体形态可见椭圆状、圆状、透镜状以及不规则状,大小差异较大,包体常具淬冷边,证明岩浆发生混合作用(王德滋等,2008;张建军等,2012);Mg#值可以指示壳源岩浆作用是否有幔源物质的参与,在地幔组分参与时,才能导致熔体的Mg#值大于40(Rapp et al., 1995),岩石MgO含量介于3.13%~3.53%,Mg#值介于0.64~0.66,明显高于40,表明岩体源岩明显具幔源岩浆加入。
基于上述讨论,罗城花岗闪长岩为壳源岩浆与幔源岩浆发生混合作用的产物,这种作用是由于地壳深部存在强烈的地幔岩浆底侵作用,导致新生地壳部分熔融并混入底侵的幔源物质。幔源的高温基性岩浆底侵,为其提供了少量物质来源,使岩石地球化学特征上既表现出壳源特征,也表现出幔源物质的信息。
5.3 构造背景
罗城黑云母花岗闪长岩富集Rb、Th、K等大离子亲石元素和轻稀土元素,亏损Nb、Ta、P、Ti等高场强元素,具有典型的岛弧岩浆岩特征(王秉璋等,2021),其形成与大洋板片俯冲消减作用有关。通过对黑云母花岗闪长岩构造背景判别,在Rb-(Y+Nb)(图11a)、Nb-Y(图11b)及Hf-Rb/30-3Ta(图11c)图解中,样品均落在火山弧花岗岩区域;在R1-R2(图11d)图解中,样品落在地幔分异花岗岩与碰撞前花岗岩交界区域。
图 11 花岗闪长岩构造背景判别Rb-(Y+Nb)(a)、Nb-Y(b)(据Pearce et al., 1984)、Hf-Rb/30-3Ta(c)(据Harris et al., 1986)图解及R1-R2(d)(据Batchelor et al., 1985)图解① 地幔分异花岗岩;② 破坏性活动板块边缘 (板块碰撞前) 花岗岩;③ 板块碰撞后隆起期花岗岩;④ 晚造期花岗岩;⑤ 非造山区花岗岩;⑥ 同碰撞花岗岩;⑦造山期花岗岩Figure 11. Identification of granodiorite structural background (a) Rb-(Y+Nb), (b) Nb-Y, (c) Hf-Rb/30-3Ta and (d) R1-R2 diagram罗城岩体位于龙首山造山带的西南缘大陆边缘活动带和祁连裂谷的发育构成了龙首山成矿带特定的构造环境(王承花,2010)。龙首山地区地壳演化自早古生代至中新生代经历了活动-稳定-再活动-再稳定-又活动的发展阶段,其在晚古生代处于稳定的拉张环境(强利刚等,2019),早古生代祁连造山带经历了北祁连洋向南俯冲,俯冲受阻,转为向北俯冲,引起北祁连岛弧与阿拉善陆块的碰撞,从而形成了一系列火山弧I型花岗岩(夏林圻等,2003;刘文恒等,2019;王增振等,2020)。罗城二叠纪黑云母花岗闪长岩指示其形成环境为岩浆弧,且R1-R2判别图解指示其形成环境为碰撞前消减花岗岩环境,说明在晚古生代该区还存在一期俯冲碰撞活动,与前人对龙首山晚石炭世—早二叠世西山头窑地区岩体处于弧后洋盆闭合过程,是古亚洲洋向南俯冲的结果(董国强等,2022)相吻合,同时与前人认为的北山地区二叠纪时期仍发生的俯冲–增生造山过程延续可至三叠纪(宋东方等,2018)存在相关性,而并非处于拉张稳定发展期(强利刚等,2019)。
6. 结论
(1)通过对罗城黑云母花岗闪长岩LA-ICP-MS锆石U-Pb测年得出,岩石锆石结晶年龄为(289±3) Ma ,属于早二叠世,指示了区域上华力西期的强烈构造岩浆事件。
(2)通过罗城黑云母花岗闪长岩岩相学、岩石地球化学及Hf同位素特征,岩体富集Rb、Th、K等大离子亲石元素和轻稀土元素,亏损Ba、Nb、Ta、P等高场强元素,属于准铝质钙碱性I型花岗岩,是由新生地壳部分熔融并混入底侵幔源物质的产物,指示了地壳深部强烈的地幔岩浆底侵作用。
(3)罗城黑云母花岗闪长岩地球化学特征指示其形成于碰撞前的消减花岗岩环境,结合龙首山地区构造演化历史,表明该区在晚古生代还存在一期俯冲碰撞,而并非一直处于拉张稳定发展期。
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图 7 王庄金矿Au、As关系图解(数据来自表1)
a. 含砷黄铁矿中Au、As关系散点图;b. 毒砂中As、Au柱状图
Figure 7. Relationship diagram of Fe, S, Au and As in Wangzhuang gold deposit
表 1 王庄金矿床矿石中黄铁矿、毒砂电子探针分析结果(%)
Table 1 Electron probe analysis results of pyrite and arsenopyrite in Wangzhuang gold deposit (%)
样品编号 矿物类型 As Zn Cu Ni Co Fe Sb Ag Bi Pb S Au Total ZK7-1BT4 I-py 0.564 0 0 0.031 0.087 46.08 0 0 0.011 0.101 52.881 0 99.755 I-py 2.508 0.007 0.012 0.022 0.054 44.983 0 0 0 0 53.724 0 101.31 II-py 2.276 0.022 0.068 0.091 0.07 45.351 0 0.006 0 0 50.586 0 98.47 II-py 4.218 0 0 0.01 0.069 45.376 0.021 0.029 0 0.011 50.432 0.01 100.176 II-py 4.055 0.052 0 0.16 0.11 44.676 0.059 0 0.016 0 50.624 0 99.752 II-py 6.68 0 0.01 0.156 0.072 44.272 0.018 0 0 0 46.418 0.018 97.644 Apy 39.466 0 0.028 0.068 0.094 34.134 0.071 0 0 0 24.022 0.037 97.92 Apy 41.206 0 0.04 0 0.045 34.468 0.079 0 0 0.207 23.26 0 99.305 Apy 40.423 0 0.015 0 0.044 34.55 0.08 0.047 0 0 23.111 0.045 98.315 Apy 42.555 0 0 0 0.089 34.585 0.019 0 0 0.049 22.65 0.029 99.976 Apy 41.116 0 0 0.096 0.059 33.959 0.206 0.006 0 0 22.881 0 98.323 Apy 41.975 0 0 0 0.041 34.209 0.022 0 0 0 22.648 0 98.895 Apy 42.433 0.087 0 0 0 34.654 0.07 0.022 0 0.061 21.882 0.091 99.3 Apy 39.188 0.013 0 0 0.07 33.597 0.077 0 0 4.009 22.57 0 99.524 Apy 43.225 0.001 0.012 0 0.027 34.201 0 0.003 0 0 22.102 0.108 99.679 Apy 42.925 0.015 0.01 0.011 0.03 34.03 0.006 0.009 0 0 21.999 0.017 99.052 Apy 44.282 0.051 0 0.066 0.024 34.297 0.036 0.001 0 0.075 21.585 0 100.417 Apy 44 0.022 0.025 0.031 0.007 33.894 0.01 0 0 0 21.782 0 99.771 ZK7-1TZ1 Apy 44.252 0.01 0 0 0.046 33.97 0.019 0 0 0 21.021 0.017 99.335 I-py 0.074 0 0.013 0 0.039 46.113 0.036 0.004 0 0 53.708 0 99.987 I-py 1.247 0.007 0.017 0.082 0.096 45.815 0.025 0.015 0 0.047 52.233 0 99.584 III-py 0.647 0 0 0.106 0.401 44.042 0.032 0.004 0 0 52.629 0.003 97.864 III-py 3.113 0 0.027 0.412 0.199 45.183 0.035 0 0 0 51.119 0 100.088 III-py 2.417 0 0 0.116 0.168 43.772 0.064 0.021 0 0.056 50.495 0 97.109 Apy 42.448 0.057 0.014 0 0.058 34.184 0.04 0 0 0.021 22.439 0.055 99.316 Apy 43.778 0.019 0.052 0.034 0.043 34.3 0 0 0 0.066 21.448 0.119 99.859 Apy 44.609 0.004 0 0 0.022 34.09 0 0.011 0 0 21.386 0.068 100.19 Apy 41.142 0.012 0.034 0 0.059 33.175 0.101 0 0 0 21.17 0.135 95.828 ZK7-1TZ2 I-py 1.99 0.017 0.043 0.382 0.173 45.417 0 0 0 0 51.978 0 100 I-py 0.111 0 0.062 0.018 0.097 44.793 0.034 0.003 0 0 52.656 0 97.774 I-py 2.799 0 0.021 0.084 0.008 45.416 0 0.044 0 0 51.559 0 99.931 I-py 2.776 0 0 0 0.038 45.561 0.022 0.007 0 0 51.232 0 99.636 II-py 1.134 0.045 0.005 0.184 0.277 44.576 0.042 0.037 0 0 52.241 0.02 98.561 II-py 2.444 0 0.023 0.026 0.084 44.845 0 0 0 0 51.637 0.06 99.119 II-py 3.752 0 0.023 0 0.04 45.091 0 0.009 0 0 50.617 0.058 99.59 II-py 3.938 0 0.003 0.999 0.44 44.02 0.017 0 0.012 0 50.332 0 99.761 II-py 1.293 0.003 0 0.153 0.253 42.633 0.013 0.019 0 0.147 50.286 0.003 94.803 Apy 41.809 0 0.026 0.267 0.061 34.506 0.021 0.001 0 0 23.301 0 99.992 Apy 43.142 0 0.045 0 0.044 34.621 0.059 0 0 0.005 22.48 0.012 100.408 Apy 43.085 0.029 0.016 0.019 0.034 34.545 0.036 0 0 0.02 22.4 0.045 100.229 Apy 42.46 0 0 0.129 0.086 34.394 0 0 0 0 22.099 0 99.168 Apy 44.269 0 0 0 0.039 34.351 0.001 0 0 0.072 21.305 0.046 100.083 Apy 44.269 0 0 0 0.039 34.351 0.001 0 0 0.072 21.305 0.046 100.083 Apy 44.197 0 0.001 0 0.048 33.929 0 0.025 0 0 21.38 0 99.58 Apy 40.299 0 0.06 0.051 0.042 33.936 0.001 0.017 0 0.005 21.195 0.021 95.627 Apy 44.005 0 0.025 0.04 0.064 34.026 0 0.031 0 0 20.809 0.037 99.037 ZK7-1TZ3 I-py 0.075 0.036 0 0.012 0.054 46.366 0.024 0 0 0 53.35 0.055 99.972 I-py 0.178 0 0 0 0.058 46.249 0.012 0.012 0 0.066 52.599 0 99.174 II-py 2.805 0 0.005 0 0.045 45.825 0 0 0 0 52.271 0.014 100.965 II-py 1.217 0 0.015 0.059 0.439 45.343 0.018 0.006 0 0.039 52.461 0 99.597 II-py 2.099 0 0.026 0.022 0.034 45.677 0.026 0.002 0 0 51.588 0.041 99.515 II-py 2.331 0 0 0 0.017 45 0.038 0.023 0 0 52.186 0 99.595 II-py 2.97 0 0 0 0.091 45.284 0.021 0 0 0 51.495 0.092 99.953 II-py 2.289 0.037 0 0 0.037 45.099 0.014 0.022 0 0.072 51.426 0.027 99.023 III-py 1.844 0 0 0.396 0.188 44.829 0.027 0 0 0 51.634 0.01 98.928 III-py 2.187 0.002 0.032 0.038 0.052 44.741 0.008 0.035 0 0.004 51.49 0 98.589 II-py 3.836 0.059 0.027 0.024 0.081 44.973 0 0.019 0 0 50.352 0.003 99.374 II-py 4.142 0 0.056 0.128 0.057 44.851 0 0 0 0.143 50.346 0 99.723 II-py 1.738 0 0 0.109 0.092 43.853 0.017 0 0 0.022 50.521 0.064 96.416 Apy 40.827 0.029 0.007 0 0.044 34.922 0.005 0.01 0 0 24.062 0 99.906 Apy 41.213 0 0.009 0.015 0.085 34.878 0.021 0 0 0.031 23.81 0.053 100.115 Apy 41.462 0 0 0.032 0.026 34.819 0.023 0.042 0 0.005 23.347 0.074 99.83 Apy 41.151 0 0.029 0.182 0.038 34.52 0 0 0 0 23.181 0 99.101 Apy 42.363 0.012 0.006 0 0.065 34.737 0 0.025 0 0 23.015 0.017 100.24 Apy 41.994 0.037 0 0 0.048 34.393 0.02 0.003 0 0.071 22.788 0 99.354 Apy 42.254 0.01 0.052 0.003 0.055 34.4 0.012 0 0 0 22.725 0.058 99.569 Apy 42.012 0 0.018 0 0.017 34.526 0.054 0.048 0 0 22.506 0.042 99.223 Apy 41.686 0.004 0 0 0.033 34.073 0.037 0 0 0 22.739 0 98.572 Apy 43.393 0.017 0.018 0.042 0.042 34.4 0 0 0 0 22.301 0.091 100.304 Apy 42.447 0 0.006 0 0.055 33.781 0.003 0.013 0 0.031 22.603 0.14 99.079 Apy 43.158 0 0.01 0.053 0.024 33.841 0.039 0 0 0.005 21.977 0 99.107 Apy 43.05 0 0 0.001 0.018 34.067 0 0 0 0.08 21.499 0.07 98.785 Apy 44.064 0 0 1.328 0.105 32.694 0.004 0.013 0 0 21.542 0.038 99.788 II-py 6.731 0 0.108 0.06 0.099 44.595 0 0.003 0 0.029 49.508 0.035 101.168 ZK7-1TZ4 I-py 0.019 0.044 0 0 0.022 46.858 0.003 0.001 0 0 53.404 0 100.351 I-py 0.035 0 0 0 0.087 46.57 0 0.005 0.018 0 53.513 0 100.228 I-py 0.032 0.034 0 0.088 0.025 46.471 0.012 0.014 0 0 53.252 0 99.928 III-py 0 0 0.044 0.003 0.002 45.485 0 0.002 0 0.044 53.612 0.051 99.243 Apy 43.192 0.027 0.001 0.025 0.031 33.552 0.02 0.014 0 0 21.252 0.074 98.188 I-py 0 0.01 0.024 0.014 0.08 46.771 0.01 0.01 0 0.015 53.489 0.01 100.433 I-py 0 0.032 0 0.056 0.093 45.381 0.012 0 0 0 54.206 0 99.78 I-py 0.284 0.05 0 0.053 0.076 45.338 0.019 0 0 0.018 52.611 0.048 98.497 I-py 0.542 0 0.057 0.115 0.182 45.446 0.003 0.035 0 0 52.781 0.01 99.171 I-py 0.712 0 0.043 0.121 0.198 45.433 0.017 0 0 0.013 52.657 0.01 99.204 ZK7-2TZ01 III-py 0.096 0 0.035 0.065 0.011 45.759 0.004 0.003 0 0.074 53.309 0.127 99.483 III-py 0.099 0 0.05 0.065 0.068 45.586 0.049 0.005 0 0.089 52.903 0 98.914 III-py 0.216 0.068 0.041 0.056 0.109 45.42 0.082 0.016 0 0.177 52.06 0.033 98.278 III-py 0.392 0 0.096 0.111 0.262 44.737 0 0 0 0.201 52.305 0 98.104 III-py 0.254 0.053 0.074 0.098 0.132 44.656 0.021 0.024 0 0.093 51.978 0.003 97.386 III-py 0.078 0 0 0.013 0.079 44.428 0.015 0.009 0.008 0 51.13 0 95.76 ZK7-2TZ1 II-py 0.699 0.015 0.038 0.231 0.089 45.035 0.007 0 0 0.013 53.807 0.027 99.961 II-py 3.577 0.01 0.028 0.333 0.277 44.037 0.036 0.028 0 0.078 50.641 0.145 99.19 Apy 42.003 0.086 0.013 0 0.03 34.207 0.091 0.019 0 0 22.521 0 98.97 Apy 43.236 0.034 0.054 0 0.019 34.148 0.08 0 0 0.018 22.172 0 99.761 Apy 44.022 0 0 0 0.01 33.962 0 0.002 0 0 21.851 0.16 100.007 Apy 42.502 0.078 0.022 0 0.019 33.894 0 0.024 0 0.136 21.289 0.219 98.183 ZK7-2TZ3 III-py 0.138 0.078 0.029 0.081 0.17 46.323 0.026 0.042 0 0.118 53.032 0.093 100.13 III-py 0.052 0.047 0.005 0.484 0.173 46.049 0 0 0 0 53.232 0.066 100.108 III-py 0.137 0 0.077 0.124 0.2 45.586 0.044 0.014 0 0.146 53.093 0 99.421 III-py 0.068 0 35.467 0.137 0.053 29.769 0 0.031 0 0 35.239 0.029 100.793 ZK7-2TZ4 III-py 0.846 0 0 0 0.077 45.429 0.022 0 0 0 52.774 0 99.148 III-py 0.334 0.064 0.06 0.033 0.216 45.29 0.014 0 0 0 51.871 0.03 97.912 III-py 0.139 0.037 0.052 0.072 0.186 44.657 0.043 0 0 0 52.297 0.007 97.49 II-py 4.224 0.017 0.038 0.028 0.062 45.786 0.009 0 0 0 50.672 0.059 100.895 II-py 4.603 0 0.038 0.166 0.046 45.47 0.029 0.012 0 0 50.103 0.042 100.509 II-py 5.055 0.012 0.02 0.08 0.07 45.211 0 0.016 0 0 50.245 0.01 100.719 Apy 40.241 0 0 0 0.08 34.829 0 0 0 0 24.283 0.099 99.532 Apy 39.389 0 0.003 0 0.017 34.577 0.145 0 0 0.01 24.089 0.012 98.242 Apy 41.54 0.016 0 0.018 0.021 34.842 0.025 0 0 0.005 23.595 0.025 100.087 Apy 43.246 0 0.007 0.005 0.046 34.509 0.008 0.016 0 0.023 23.084 0.029 100.973 Apy 42.95 0.01 0 0 0.037 34.584 0.03 0.007 0 0 22.381 0.013 100.012 Apy 44.053 0 0.022 0.087 0.028 34.007 0.006 0 0 0.018 21.841 0.08 100.142 Apy 40.809 0 0.047 0 0.02 33.195 0.069 0 0 0.033 22.249 0.05 96.472 Apy 40.594 0.004 0 0.005 0.069 32.841 0.005 0.002 0 0.044 21.676 0.099 95.339 I-py 0.087 0.003 0 0.084 0.069 46.498 0 0 0 0.028 53.26 0.024 100.053 I-py 0.087 0.014 0 0.018 0.08 46.379 0.002 0.022 0 0.02 53.269 0 99.891 ZK7-2TZ4 II-py 1.816 0 0.017 0 0.019 46.91 0.022 0.001 0 0 52.041 0 100.826 II-py 4.441 0.005 0.018 0.054 0.045 45.129 0.052 0 0 0 51.863 0.073 101.68 II-py 5.265 0 0.025 0.082 0.054 44.116 0.046 0.002 0 0 48.946 0.651 99.187 II-py 7.653 0.025 0.02 0.041 0.029 44.91 0.008 0 0 0 47.849 0.078 100.613 I-py 0 0.034 35.37 0 0.016 30.507 0.004 0.011 0 0 34.809 0 100.751 I-py 0 0.122 35.132 0 0.037 30.009 0.111 0.034 0 0.05 34.712 0.03 100.237 Apy 41.991 0.022 0 0 0.024 34.643 0.038 0.008 0 0 23.15 0.096 99.972 Apy 42.883 0 0.024 0.115 0.016 34.524 0 0.002 0 0 22.324 0.13 100.018 Apy 43.487 0.056 0.004 0.088 0.04 34.272 0.014 0.023 0 0.031 22.091 0.114 100.22 Apy 48.284 0.02 0 0.008 0.067 33.757 0.019 0 0 0.069 20.271 0 102.495 ZK7-2TZ5 I-py 0 0.008 0 0.053 0.049 46.789 0.011 0 0 0 53.767 0 100.677 I-py 0.104 0.05 0 0.006 0.096 45.864 0.016 0.039 0 0 54.041 0.003 100.219 I-py 0 0.017 0.003 0.024 0.065 46.367 0.01 0.033 0 0.045 53.375 0 99.939 I-py 0.11 0 0.031 0.062 0.138 46.232 0.01 0 0 0 53.16 0 99.743 I-py 0.086 0.01 0.071 0.293 0.108 45.409 0.076 0.007 0 0.047 52.865 0 98.972 I-py 0.036 0 0.043 0.077 0.072 45.174 0.04 0 0 0 52.565 0 98.007 I-py 0.106 0.045 0.007 0.515 0.137 44.688 0.026 0 0 0.037 52.62 0 98.181 I-py 0.122 0.038 0.021 0.192 0.117 44.356 0.055 0 0 0.006 51.775 0 96.682 I-py 0.07 0.033 0 0.269 0.129 43.787 0.04 0.018 0 0 50.751 0 95.097 I-py 0.142 0.018 0 0.189 0.138 42.336 0.009 0 0 0.045 49.969 0 92.846 注:由中国地质调查局西安地质调查中心实验室测试。I-py为I阶段黄铁矿;II-py为II阶段黄铁矿;III-py为III阶段黄铁矿;Apy为II阶段毒砂。 -
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