Petrogenesis of the granites in Sandun area-Constraints from petrochemistry, zircon U-Pb chronology and Hf Isotope
-
摘要:
对湘东北三墩铜铅锌矿区花岗岩进行了系统的锆石U-Pb年代学、岩石地球化学和Hf同位素分析。LA-ICP-MS锆石U-Pb定年表明，三墩铜铅锌矿区花岗岩成岩年龄为131.9±1.1Ma。三墩铜铅锌矿区花岗岩为一套强过铝质钙碱性系列花岗岩，富集U、Ta、Pb，亏损Ba、Nb、Sr、Zr、Ti等元素，稀土元素配分模式为右倾配分模式，具有弱负Eu异常。Hf同位素分析表明，三墩铜铅锌矿区花岗岩燕山晚期锆石εHf（t）值为-5.9~-2.4，Hf同位素二阶段模式年龄为1558~1338Ma，表明其物质来源于中元古代古老地壳岩石部分熔融。749.5Ma继承锆石核的εHf（t）值为+4.8，Hf同位素二阶段模式年龄为1355Ma，暗示其物质来源有幔源物质加入。三墩铜铅锌矿区花岗岩可能是由于中下地壳的熔融岩浆形成后，混入少量幔源物质上侵形成的。
Abstract:In this paper, the authors studied the petrogenesis and tectonic-significance of the granite from the Sandun Cu-Pb-Zn polymetallic deposit in northeastern Hu'nan Province by means of zircon U-Pb isotope chronology, whole rock geochemistry and Hf isotope. LA-ICP-MS zircon U-Pb dating yielded crystallization age of 131.9±1.1Ma for the Sandun granite. The Sandun granite is a peraluminous high-Al calc-alkaline intrusive granite. The rocks are characterized by high U, Ta, Pb and low Ba, Nb, Sr, Zr, Ti val-ues. The REE distribution patterns are strongly LREE enriched and HREE depleted, with weakly negative Eu anomalies. The Hf iso-tope analyses show that the εHf(t) values of the late Yanshanian granite zircons are between -5.9 and -2.4, and the two stage Hf model ages ranging from 1558Ma to 1338Ma, which indicates that its parental magma was derived from partial melting of rocks of Middle Proterozoic paleo-crust. Inherited zircon with an age of 749.5Ma has the εHf(t) of +4.8 and two stage Hf model age of 1355Ma, re-spectively, which indicates that its parental magma was mainly derived from the mantle. The Sandun granite probably resulted from the formation of the molten magma in the middle and lower crust and the formation of a small amount of mantle derived material.
-
Key words:
- Qinzhou-Hangzhou metallogenic belt /
- Mufushan granite /
- zircon U-Pb dating /
- Hf isotope
-
-
表 1 花岗岩LA-ICP-MS锆石U-Th-Pb同位素测试结果
Table 1. LA-ICP-MS U-Th-Pb isotopic compositions of zircons for the granite
分析
点含量/10-6 Th/U 同位素比值 年龄/Ma Pb Th U 207Pb/206Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ 207Pb/206Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ 1 231 323 9563 0.034 0.04826 0.00120 0.14259 0.00348 0.02115 0.00021 122.3 57.4 135.3 3.1 134.9 1.3 2 155 377 6425 0.059 0.04627 0.00127 0.13697 0.00381 0.02114 0.00023 13.1 63.0 130.3 3.4 134.8 1.5 3 103 243 4266 0.057 0.04430 0.00125 0.13036 0.00375 0.02102 0.00024 error error 124.4 3.4 134.1 1.5 4 174 358 7255 0.049 0.04723 0.00137 0.13570 0.00381 0.02056 0.00022 61.2 66.7 129.2 3.4 131.2 1.4 5 101 240 4245 0.057 0.04742 0.00182 0.13820 0.00545 0.02082 0.00030 77.9 88.9 131.4 4.9 132.8 1.9 6 109 279 4578 0.061 0.05025 0.00160 0.14233 0.00446 0.02024 0.00022 205.6 74.1 135.1 4.0 129.2 1.4 7 84 224 3476 0.064 0.04772 0.00160 0.13724 0.00451 0.02058 0.00023 87.1 -117.6 130.6 4.0 131.3 1.5 8 110 259 4530 0.057 0.04652 0.00146 0.13614 0.00420 0.02097 0.00021 33.4 64.8 129.6 3.8 133.8 1.3 9 81 211 3513 0.060 0.04946 0.00318 0.14136 0.00903 0.02063 0.00034 168.6 154.6 134.3 8.0 131.7 2.1 10 233 376 10530 0.036 0.04686 0.00134 0.13658 0.00453 0.02102 0.00042 42.7 66.7 130.0 4.0 134.1 2.6 11 120 375 5185 0.072 0.04865 0.00152 0.13863 0.00437 0.02049 0.00026 131.6 78.7 131.8 3.9 130.7 1.6 12 79 192 3258 0.059 0.04918 0.00166 0.14283 0.00465 0.02097 0.00021 166.8 79.6 135.6 4.1 133.8 1.3 13 148 399 6305 0.063 0.04854 0.00110 0.13748 0.00307 0.02040 0.00017 124.2 55.6 130.8 2.7 130.2 1.1 14 210 561 9618 0.058 0.04795 0.00103 0.12706 0.00283 0.01910 0.00017 98.2 45.4 121.5 2.5 122.0 1.1 15 392 963 2472 0.390 0.06553 0.00086 1.11877 0.01526 0.12330 0.00078 790.7 27.8 762.4 7.3 749.5 4.5 16 38 286 1581 0.181 0.04736 0.00244 0.13302 0.00626 0.02055 0.00029 77.9 109.3 126.8 5.6 131.1 1.8 17 141 371 6038 0.061 0.04796 0.00111 0.13634 0.00319 0.02040 0.00016 98.2 53.7 129.8 2.9 130.2 1.0 18 138 326 5740 0.057 0.04908 0.00174 0.14255 0.00407 0.02112 0.00021 150.1 83.3 135.3 3.6 134.7 1.3 19 145 358 6175 0.058 0.04931 0.00142 0.14325 0.00423 0.02089 0.00025 161.2 66.7 135.9 3.8 133.2 1.6 20 154 398 6752 0.059 0.04837 0.00138 0.13621 0.00389 0.02022 0.00017 116.8 63.9 129.7 3.5 129.0 1.1 
下载: 导出CSV
表 2 花岗岩主量、微量和稀土元素含量
Table 2. Major, trace and rare earth element values of the granite
样号
岩性SD1-4
二云母
花岗岩SD1-5
二云母
花岗岩SD2-2
二云母
花岗岩SD3-1
二云母
花岗岩SD4-1
二云母
花岗岩SiO2 72.70 72.56 74.27 73.49 73.49 Al2O3 14.45 14.46 14.18 14.35 14.05 Fe2O3 0.501 0.383 0.250 0.228 0.237 FeO 1.88 2.04 1.73 1.77 2.34 CaO 0.553 1.02 0.475 0.732 0.739 MgO 0.325 0.346 0.184 0.231 0.320 K2O 5.61 4.50 4.77 5.00 4.22 Na2O 3.20 3.66 3.08 3.12 3.49 TiO2 0.125 0.107 0.106 0.127 0.165 P2O5 0.201 0.181 0.267 0.215 0.111 MnO 0.034 0.035 0.050 0.039 0.064 灼失量 0.399 0.277 0.419 0.459 0.460 Cu 13.5 15.0 19.6 17.8 12.7 Pb 65.0 90.3 28.2 43.2 43.5 Zn 108 59.4 47.0 57.9 146 Cr 14.5 3.86 17.9 7.27 9.28 Ni 2.25 2.29 2.65 19.4 5.07 Co 1.70 1.54 1.20 1.42 2.12 W 2.19 2.14 3.12 3.27 2.29 Mo 0.85 0.55 0.89 Bi 1.04 1.25 1.45 4.82 0.22 Sr 42.4 63.3 18.1 33.3 38.8 Ba 251 199 78.9 163 226 Nb 17.3 14.8 18.6 Ta 2.86 2.57 4.89 Zr 48.0 59.9 51.2 Hf 2.26 2.52 1.97 U 17.2 8.02 8.00 Th 6.55 9.92 10.7 La 22.8 15.7 12.7 17.4 20.7 Ce 36.1 27.2 26.6 35.8 40 Pr 5.5 4.02 3.16 4.37 4.73 Nd 18.9 14 10.9 15.1 16.2 Sm 4.49 3.39 2.67 3.81 3.78 Eu 0.47 0.4 0.25 0.46 0.54 Gd 3.83 2.93 2.26 3.32 3.39 Tb 0.58 0.46 0.45 0.56 0.57 Dy 2.56 2.05 2.5 2.54 2.64 Ho 0.36 0.29 0.44 0.35 0.42 Er 0.87 0.73 1.24 0.81 1.09 Tm 0.12 0.093 0.24 0.11 0.2 Yb 0.74 0.58 1.51 0.74 1.39 Lu 0.094 0.071 0.19 0.091 0.19 Y 9.27 7.49 12.7 9.43 11.8 A/CNK 1.17 1.13 1.28 1.21 1.21 ∑REE 106.68 79.40 77.81 94.89 107.64 δEu 0.35 0.39 0.31 0.40 0.46 δCe 0.79 0.84 1.03 1.01 0.99 注：主量元素含量单位为%，微量和稀土元素含量为10-6
下载: 导出CSV
表 3 锆石Lu-Hf同位素分析结果
Table 3. Lu-Hf isotope data of zircons
分析点 176Hf/177Hf
比值2σ 176Lu/177Hf
比值2σ 176Yb/177Hf
比值2σ t/Ma εHf(t) T1DM/Ma T2DM/Ma fLu/Hf 1 0.282554 0.000018 0.000975 0.000003 0.026140 0.000080 131.9 -4.9 988 1496 -0.97 2 0.282570 0.000017 0.000971 0.000008 0.025686 0.000242 131.9 -4.4 966 1460 -0.97 4 0.282526 0.000021 0.000974 0.000004 0.025628 0.000105 131.9 -5.9 1028 1558 -0.97 6 0.282584 0.000016 0.000732 0.000009 0.019666 0.000251 131.9 -3.8 939 1426 -0.98 7 0.282605 0.000019 0.000830 0.000020 0.021906 0.000564 131.9 -3.1 912 1380 -0.98 8 0.282600 0.000014 0.001043 0.000011 0.027627 0.000318 131.9 -3.3 925 1392 -0.97 9 0.282597 0.000019 0.000897 0.000002 0.024262 0.000049 131.9 -3.4 926 1399 -0.97 10 0.282624 0.000016 0.001042 0.000014 0.027703 0.000383 131.9 -2.4 890 1338 -0.97 11 0.282614 0.000028 0.001068 0.000004 0.029513 0.000140 131.9 -2.8 906 1361 -0.97 12 0.282588 0.000017 0.000782 0.000004 0.020700 0.000127 131.9 -3.7 935 1418 -0.98 13 0.282616 0.000016 0.001003 0.000014 0.026896 0.000377 131.9 -2.7 901 1355 -0.97 15 0.282453 0.000018 0.000985 0.000004 0.023484 0.000117 749.5 4.8 1130 1355 -0.97 16 0.282575 0.000015 0.000511 0.000002 0.013413 0.000053 131.9 -4.1 946 1445 -0.98 17 0.282595 0.000019 0.001079 0.000005 0.028965 0.000139 131.9 -3.4 932 1403 -0.97 18 0.282541 0.000021 0.000971 0.000006 0.025835 0.000161 131.9 -5.4 1006 1524 -0.97 19 0.282619 0.000021 0.000940 0.000002 0.024897 0.000063 131.9 -2.6 896 1349 -0.97 20 0.282613 0.000016 0.001165 0.000002 0.031296 0.000053 131.9 -2.8 910 1364 -0.96
下载: 导出CSV
-
[1] 杨明桂, 梅勇文.钦-杭古板块结合带与成矿带的主要特征[J].华南地质与矿产, 1997, (3):52-59. http://www.cnki.com.cn/Article/CJFDTOTAL-HNKC199703008.htm
[2] 徐德明, 蔺志永, 龙文国, 等.钦杭成矿带的研究历史和现状[J].华南地质与矿产, 2012, 28(4):277-289. http://www.cnki.com.cn/Article/CJFDTOTAL-HNKC201204001.htm
[3] 张鲲, 徐德明, 胡俊良.湖南桃林铅锌矿区花岗岩地球化学特征及其与成矿的关系[J].华南地质与矿产, 2012, 28(4):307-314. http://www.cnki.com.cn/Article/CJFDTOTAL-HNKC201204003.htm
[4] 路远发. Geokit:一个用VBA构建的地球化学工具软件包[J].地球化学, 2004, 33(5):459-464. http://www.cnki.com.cn/Article/CJFDTOTAL-DQHX200405003.htm
[5] Liu Y S, Hu Z C, Gao S, et al. In situ analysis of major and trace ele-ments of anhydrous minerals by LA-ICP-MS without applying an internal standard[J]. Chemical Geology, 2008, 257(1/2):34-43. http://www.sciencedirect.com/science/article/pii/S0009254108003501
[6] Liu Y S, Gao S, Hu Z C, et al. Continental and oceanic crust recy-cling-induced melt-peridotite interactions in the Trans-North Chi-na Orogen:U-Pb dating, Hf isotopes and trace elements in zircons of mantle xenoliths[J]. Journal of Petrology, 2010, 51(1 & 2):537-571. http://www.academia.edu/13671274/Destruction_of_the_North_China_Craton
[7] Ludwig K R. ISOPLOT 3.00:A Geochronological Toolkit for Mi-crosoft Excel[J]. Berkeley Geochronology Center, California, Berke-ley, 2003, 39. https://searchworks.stanford.edu/view/6739593
[8] 徐平, 吴福元, 谢烈文, 等. U-Pb同位素定年标准锆石的Hf同位素[J].科学通报, 2004, 49:1403-1410. doi: 10.3321/j.issn:0023-074X.2004.14.012
[9] Yuan H L, Gao S, Dai M N, et al. Simultaneous determinations of U-Pb age, Hf isotopes and trace element compositions of zircon by excimer laser ablation quadrupole and multiple collector ICP-MS[J]. Chem. Geol., 2008, 247:100-118. doi: 10.1016/j.chemgeo.2007.10.003
[10] 吴元保, 郑永飞.锆石成因矿物学研究及其对U-Pb年龄解释的制约[J].科学通报, 2004, 49(16):1589-1604. doi: 10.3321/j.issn:0023-074X.2004.16.002
[11] Irvine T N, Baragar W R A. A guide to chemical classification clas-sification of the common volcanic rocks[J]. Canadian Journal of Earth Sciences, 1971, 8:532-548. http://www.nrcresearchpress.com/doi/abs/10.1139/e71-055?cookieSet=1
[12] Middlemost E A K. Naming materials in the magma/igneous rock system[J]. Earth Sci. Rev., 1994, 37:15-224. http://www.oalib.com/references/19769933
[13] Peceerillo R, Taylor S R. Geochemistry of Eocene calcalkaline vol-canic rocks from the Kastamonu area, northern Turkey[J]. Contrib. Mineral. Petrol., 1976, 58:63-81. doi: 10.1007/BF00384745
[14] Green T H, Pearson N J. An experimental study of Nb and Ta par-titioning between Ti-rich minerals and silicate liquids at high pres-sure and temperature[J]. Geochim. Cosmochim. Acta, 1987, 51:55-62. doi: 10.1016/0016-7037(87)90006-8
[15] Green T H. Significance of Nb/Ta as an indicator of geochemical process in the crust-mantle system[J]. Chemical Geology, 1995, 120:347-359. doi: 10.1016/0009-2541(94)00145-X
[16] Barth M G, McDonough W F, Rudnick R L. Tracking the budget of Nb and Ta in the continental crust[J]. Chemical Geology, 2000, 165:195-213. http://www.sciencedirect.com/science/article/pii/S0009254199001734
[17] Cherniak D J, Watson E B. Pb diffusion in zircon[J]. Chemical Ge-ology, 2000, 172:5-24. http://link.springer.com/content/pdf/10.1007%2Fs00269-007-0210-6.pdf
[18] 付建明, 马昌前, 谢才富, 等.湖南骑田岭岩体东缘菜岭岩体的锆石SHRIMP定年及其意义[J].中国地质, 2004, 33(1):96-100. http://www.cnki.com.cn/Article/CJFDTOTAL-DIZI200401013.htm
[19] 马铁球, 柏道远, 邝军, 等.湘东南茶陵地区锡田岩体锆石SHRIMP定年及其地质意义[J].地质通报, 2005, 24(5):415-419. http://dzhtb.cgs.cn/ch/reader/view_abstract.aspx?flag=1&file_no=20050582&journal_id=gbc
[20] 朱金初, 张佩华, 谢才富, 等.桂东北里松花岗岩中暗色包体的岩浆混合成因[J].地球化学, 2006, 35(5):506-51. http://www.cnki.com.cn/Article/CJFDTOTAL-DQHX200605005.htm
[21] 吴福元, 李献华, 郑永飞, 等. Lu-Hf同位素体系及其岩石学应用[J].岩石学报, 2007, 23(2):185-220. http://www.cnki.com.cn/Article/CJFDTOTAL-YSXB200702002.htm
[22] 毛景文, 陈懋弘, 袁顺达.华南地区钦杭成矿带地质特征和矿床时空分布规律[J].地质学报, 2011, 85(5):636-658. http://www.cnki.com.cn/Article/CJFDTOTAL-DZXE201105006.htm
[23] 毛景文, 谢桂青, 郭春丽, 等.南岭地区大规模钨锡多金属成矿作用:成矿时限及地球动力学背景[J].岩石学报, 2008, 23(10):2329-2338. http://www.cnki.com.cn/Article/CJFDTOTAL-YSXB200710003.htm
[24] 贾大成, 胡瑞忠, 卢焱, 等.湘东北蕉溪岭富钠煌斑岩地球化学特征[J].岩石学报, 2002, 18(4):459-467. http://www.cnki.com.cn/Article/CJFDTOTAL-YSXB200204002.htm
[25] 李献华, 胡瑞忠, 饶冰.粤北白垩纪基性岩脉的年代学和地球化学[J].地球化学, 1997, 26(2):14-31. http://www.cnki.com.cn/Article/CJFDTOTAL-DQHX702.003.htm
[26] 郭峰, 范蔚茗, 林舸, 等.湖南道县辉长岩包体的年代学研究及成因探讨[J].科学通报, 1997, 42(15):1661-1664. doi: 10.3321/j.issn:0023-074X.1997.15.022
[27] 付建明, 马昌前, 谢才富, 等.湖南九嶷山复试花岗岩体SHRIMP锆石定年及其地质意义[J].大地构造与成矿学, 2004, 28(4):370-378. http://www.cnki.com.cn/Article/CJFDTOTAL-DGYK200404002.htm
[28] 魏道芳, 鲍征宇, 付建明.湖南铜山岭花岗岩体的地球化学特征及锆石SHRIMP定年[J].大地构造与成矿学, 2007, 31(4):482-489. http://www.cnki.com.cn/Article/CJFDTOTAL-DGYK200704014.htm
① 徐德明, 张鲲, 蔺志永, 等. 钦杭成矿带(西段)重要金属矿床成矿规律及找矿方向研究. 2015.
② 湖南省地质局402地质队. 1: 20万平江幅区域地质调查. 1977.
③ 湖南省地质局402地质队. 1: 5万虹桥幅区域地质调查. 1988.
④ 赵小明, 张开明, 毛新武, 等. 中南地区矿产资源潜力评价成矿地质背景研究报告, 2013.
-
图(7)
表(3)
计量
- 文章访问数: 860
- PDF下载数: 10
- 施引文献: 0