Zircon U-Pb dating, geochemistry and geological significance of the Duobagou granite pluton on the southern margin of the Dunhuang landmass
-
摘要:
多坝沟黑云二长花岗岩体出露于敦煌地块南缘，呈近东西向带状分布，侵位于太古宙—古元古代敦煌岩群。LA-ICPMS锆石U-Pb年龄显示，该岩体形成于晚二叠世，206Pb/238U年龄加权平均值为252.1±2.3Ma。该岩体具高SiO2含量(68.32%~72.82%)和全碱含量(7.76%~8.00%)；A/CNK值为0.97~1.02，均小于1.1，为高钾钙碱性准铝质花岗岩。岩石具有明显的轻、重稀土元素分异和弱的负Eu异常，具高Sr/Yb和(La/Yb)N值富集大离子亲石元素(K、Rb、Ba、Cs)，显著亏损Nb、Ta、P和Ti，表明源岩具有经典岛弧岩石地球化学特征；(87Sr/86Sr)i值为0.707083，εNd(t)为-2.22，Nd模式年龄TDM2=1102Ma。元素和同位素地球化学特征显示，多坝沟花岗岩形成于加厚下地壳中岛弧玄武岩的部分熔融。结合岩体地质特征、年代学和区域地质背景，初步认为敦煌地块在晚古生代晚期依然受古亚洲洋汇聚碰撞相关的造山活动的影响，可能是中亚造山带的最南缘组成部分。
-
关键词:
- 花岗岩 /
- LA-ICP-MS锆石U-Pb年龄 /
- 二叠纪 /
- 敦煌地块 /
- 中亚造山带
Abstract:The Duobagou biotite monzonitic granitic pluton, distributed as a nearly EW-trending belt, intruded into Archean-Paleoproterozoic Dunhuang complexes in southern Dunhuang landmass. Zircon LA ICP-MS U-Pb data revealed the crystallization age of 252.1±2.3Ma, suggesting that Duobagou pluton was formed in Late Permian. Geochemical characteristics of monzonitic granite are similar to those of typical arc rocks. For example, the granites have high content of SiO2 (68.32%~72.82%) and total alkali (7.76%~8.00%), and their A/CNK ratios are 0.97 to 1.02, which are less than 1.1, indicating that Duobagou granites are high potassium calcium alkaline aluminium. They have obvious differentiation of REEs and weak Eu negative anomaly, and are characterized by strong enrichment of K, Rb, Ba and Cs and depletion of Nb, Ta, P, and Ti, with high ratios of Sr/Yb and (La/Yb)N. The sample PM04-1 shows high initial Sr isotopic ratio (0.707083), relatively low εNd(t) (-2.22) and Nd model ages (TDM2=1102Ma). The authors thus hold that the Duobagou biotite monzonitic granites may be the product of partial melting of island arc basalt in thickened low crust, and the Dunhuang landmass was likely to be involved into a series of orogenic events by the closing of the Palaeo-Asian Ocean at the end of Late Paleozoic, and possibly became the southernmost part of central Asian orogenic belt.
-
Key words:
- granites /
- LA-ICP-MS zircon U-Pb age /
- Permian /
- Dunhuang landmass /
- Central Asian orogenic belt
-
-
表 1 多坝沟花岗岩LA-ICP-MS锆石U-Th-Pb年龄测定结果
Table 1. Zircon LA-ICP-MS U-Th-Pb ages of the granite from Duobagou region
测点号 含量/10-6 Th/U 同位素比值 表面年龄/Ma 232Th 238U 207Pb/206Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ 206Pb/207Pb 1σ 207Pb/235U 1σ 206Pb/238U 1σ dtw05-01 437 583 0.75 0.05156 0.0009 0.2823 0.0051 0.03972 0.0005 266 20 253 4 251 3 dtw05-02 672 810 0.83 0.05058 0.0013 0.2744 0.0068 0.03935 0.0005 222 33 246 5 249 3 dtw05-03 541 569 0.95 0.05684 0.0021 0.3591 0.0127 0.04582 0.0007 485 49 312 9 289 5 dtw05-04 447 438 1.02 0.05119 0.0009 0.2875 0.0054 0.04075 0.0005 249 21 257 4 257 3 dtw05-05 724 670 1.08 0.05504 0.0011 0.3075 0.0064 0.04053 0.0005 414 24 272 5 256 3 dtw05-06 389 505 0.77 0.05412 0.0011 0.2992 0.0061 0.04011 0.0006 376 23 266 5 254 3 dtw05-07 478 693 0.69 0.05119 0.0009 0.2734 0.0051 0.03875 0.0005 249 21 245 4 245 3 dtw05-08 651 700 0.93 0.05163 0.0011 0.2911 0.0064 0.04091 0.0006 269 27 259 5 258 3 dtw05-09 538 445 1.21 0.05057 0.0009 0.3003 0.0056 0.04311 0.0006 221 21 267 4 272 4 dtw05-10 441 573 0.77 0.05171 0.0011 0.2790 0.0060 0.03916 0.0005 273 26 250 5 248 3 dtw05-11 537 639 0.84 0.05204 0.0009 0.2853 0.0052 0.03979 0.0005 287 20 255 4 252 3 dtw05-12 620 608 1.02 0.05197 0.0011 0.2952 0.0062 0.04122 0.0006 284 25 263 5 260 3 dtw05-13 549 603 0.91 0.05201 0.0009 0.2781 0.0049 0.03879 0.0005 286 19 249 4 245 3 dtw05-14 296 352 0.84 0.05129 0.0008 0.2823 0.0048 0.03996 0.0005 254 18 253 4 253 3 dtw05-15 357 305 1.17 0.05080 0.0009 0.2824 0.0053 0.04034 0.0005 232 21 253 4 255 3 dtw05-16 484 701 0.69 0.05382 0.0010 0.2909 0.0055 0.03921 0.0005 364 21 259 4 248 3 dtw05-17 384 463 0.83 0.05194 0.0011 0.2916 0.0064 0.04074 0.0006 283 27 260 5 257 3 dtw05-18 466 542 0.86 0.05241 0.0009 0.2818 0.0051 0.03901 0.0005 303 20 252 4 247 3 dtw05-19 375 387 0.97 0.05192 0.0009 0.2879 0.0051 0.04023 0.0005 282 20 257 4 254 3 dtw05-20 422 570 0.74 0.05581 0.0011 0.3019 0.0063 0.03925 0.0005 444 24 268 5 248 3 
下载: 导出CSV
表 2 多坝沟花岗岩体主量、微量和稀土元素组成
Table 2. Geochemical composition of major, trace and rare earth elements of Duobagou granite
样品号 PM04-1 DYQ23 DYQ24 DYQ25 DYQ26 SiO2 69.75 68.32 68.69 70.59 72.82 Al2O3 14.66 14.78 14.74 14.49 13.73 TiO2 0.35 0.39 0.40 0.32 0.25 Fe2O3 0.92 1.14 1.01 0.94 0.85 FeO 1.77 1.89 2.01 1.56 1.17 CaO 2.55 2.13 2.55 2.25 1.57 MgO 0.91 1.06 1.10 0.85 0.59 K2O 4.30 4.14 4.27 4.55 4.58 Na2O 3.48 3.78 3.48 3.39 3.43 MnO 0.07 0.08 0.08 0.07 0.05 P2O5 0.11 0.14 0.14 0.12 0.08 H2O+ 0.71 1.24 1.03 0.52 0.66 H2O- 0.10 0.14 0.14 0.14 0.11 烧失量 0.99 2.01 1.34 0.72 0.76 总计 99.85 99.86 99.84 99.85 99.88 A/NK 1.41 1.38 1.42 1.38 1.29 A/CNK 0.97 1.01 0.98 0.99 1.02 Mg# 39 39 40 39 35 Li 27.5 14.4 27.7 19.3 17.9 Be 2.42 2.57 2.40 1.88 2.74 Sc 4.61 5.40 4.75 4.51 4.05 V 41.3 37.0 36.9 32.2 28.0 Cr 5.41 7.59 6.36 6.41 5.43 Co 18.2 5.54 5.83 4.65 3.65 Ni 3.44 4.15 3.17 2.83 2.30 Cu 12.1 5.36 6.10 16.0 24.6 Zn 54.8 51.8 62.6 40.7 48.0 Ga 15.7 16.2 15.6 14.0 15.6 Rb 167 125 99.2 147 163 Sr 348 289 334 308 230 Zr 184 199 180 144 145 Nb 10.1 7.83 8.75 6.58 7.98 In 0.03 0.03 0.04 0.02 0.02 Cs 6.66 2.66 5.83 5.34 6.27 Ba 812 536 622 602 581 Hf 6.26 6.71 5.71 4.31 4.51 Ta 0.70 0.96 0.96 0.69 1.08 W 190 0.83 0.37 0.69 2.87 Pb 19.0 23.7 19.9 20.8 24.8 Bi 0.06 0.16 0.17 0.03 0.09 Th 9.25 15.1 8.73 11.1 17.7 U 1.56 2.49 1.32 1.70 3.14 F 342 467 677 451 467 La 21.3 24.4 19.8 23.2 21.5 Ce 44.1 49.4 43.9 48.6 44.1 Pr 5.29 5.74 5.31 5.51 5.01 Nd 17.5 20.5 19.4 19.1 16.9 Sm 3.00 3.71 3.61 3.13 2.79 Eu 0.81 0.91 0.96 0.85 0.59 Gd 2.72 3.51 3.33 3.13 2.82 Tb 0.42 0.56 0.56 0.43 0.39 Dy 2.25 3.24 3.13 2.33 2.10 Ho 0.43 0.67 0.64 0.47 0.45 Er 1.29 1.84 1.77 1.33 1.28 Tm 0.21 0.34 0.33 0.24 0.26 Yb 1.60 2.10 1.98 1.47 1.55 Lu 0.26 0.33 0.32 0.25 0.29 Y 12.4 18.2 17.6 12.9 12.8 ΣREE 113.5 135.4 122.6 123.0 112.8 LREE 92.0 104.6 93.0 100.4 90.9 HREE 9.2 12.6 12.1 9.7 9.1 LREE/HREE 10.0 8.3 7.7 10.4 10.0 (La/Yb)N 9.58 8.32 7.17 11.27 9.96 δEu 0.87 0.77 0.84 0.83 0.65 注:主量元素含量单位为%，微量和稀土元素为10-6，其中Au元素单位为10-9
下载: 导出CSV
表 3 多坝沟花岗岩全岩Sr-Nd同位素数据
Table 3. Sr-Nd isotopic data of the Duobagou granite
样号 Rb Sr 87Rb/86Sr 87Sr/86Sr 2σ (87Sr/86Sr)i Nd Sm 147Sm/144Nd 143Nd/144Nd 2σ (143Nd/144Nd)i εNd(0) εNd(t) fSm/Nd TDM2 /10-6 /10-6 /Ma PM04-1 166.56 347.65 1.38734 0.712058 0.000007 0.707083 17.49 3 0.103323 0.51237 0.000004 0.5122 -5.23 -2.22 -0.47 1102
下载: 导出CSV
-
[1] 张建新, 李怀坤, 孟繁聪, 等.塔里木盆地东南缘(阿尔金山)"变质基底"记录的多期构造热事件:锆石U-Pb年代学的制约[J].岩石学报, 2011, 27(1):23-46. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201101002
[2] Zhao Y, Sun Y, Diwu C R, et al. The Dunhuang block is a Paleozoic orogenic belt and part of the Central Asian Orogenic Belt (CAOB), NW China[J]. Gondwana Research, 2016, 30:207-223. doi: 10.1016/j.gr.2015.08.012
[3] 张志诚, 郭召杰, 邹冠群, 等.甘肃敦煌党河水库TTG地球化学特征, 锆石SHRIMP U-Pb定年及其构造意义[J].岩石学报, 2009, 25(3):495-505. http://d.old.wanfangdata.com.cn/Periodical/ysxb98200903002
[4] 朱涛, 王洪亮, 徐学义, 等.敦煌地块南缘石炭纪埃达克岩的发现及其地质意义[J].岩石学报, 2014, 30(2):491-502. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201402013
[5] 刘东晓, 王玉玺, 王金荣, 等.塔里木板块东南缘早二叠世角闪石岩的发现及大地构造意义[J].兰州大学学报(自然科学版), 2016, 52(2):167-178. http://www.cnki.com.cn/Article/CJFDTOTAL-LDZK201602004.htm
[6] 王玉玺, 第鹏飞, 陈万峰, 等.塔里木板块东南缘多坝沟金矿区花岗岩类年代学、地球化学特征及找矿意义[J].西北地质, 2017, 50(1):134-150. doi: 10.3969/j.issn.1009-6248.2017.01.013
[7] 王玉玺, 王金荣, 周小玲, 等. Columbia超大陆裂解:来自塔里木克拉通东南缘大红山A型花岗岩的证据[J].地质学报, 2017, 91(11):2369-2386. doi: 10.3969/j.issn.0001-5717.2017.11.001
[8] 许志琴, 杨经绥, 张建新, 等.阿尔金断裂两侧构造单元的对比及岩石圈剪切机制[J].地质学报, 1999, 73(3):193-205. doi: 10.3321/j.issn:0001-5717.1999.03.001
[9] Lu S N, Zhao G C, Wang H C, et al. Precambrian metamorphic basement and sedimentary cover of the North China Craton:a review[J]. Precambrian Research, 2008, 160(1):77-93. http://d.old.wanfangdata.com.cn/NSTLQK/10.1016-j.precamres.2007.04.017/
[10] 辛后田, 刘永顺, 罗照华, 等.塔里木盆地东南缘阿克塔什塔格地区新太古代陆壳增生:米兰岩群和TTG片麻岩的地球化学及年代学约束[J].地学前缘, 2013, (1):240-259. http://d.old.wanfangdata.com.cn/Periodical/dxqy201301020
[11] 赵燕, 朱涛, 王洪亮, 等.敦煌三危山地区晚泥盆世斜长花岗岩的发现及其地质意义[J].岩石学报, 2015, (7):1855-1869. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201507004
[12] 郑荣国, 吴泰然, 张文, 等.阿拉善地块北缘雅干花岗岩体地球化学, 地质年代学及其对区域构造演化制约[J].岩石学报, 2013, 29(8):2665-2675. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201308004
[13] Zheng R G, Wu T R, Zhang W, et al. Late Paleozoic subduction system in the northern margin of the Alxa block, Altaids:Geochronological and geochemical evidence from ophiolites[J]. Gondwana Research, 2014, 25(2), 842-858 doi: 10.1016/j.gr.2013.05.011
[14] Ge R F, Zhu W B, Wu H L, et al. The Paleozoic northern margin of the Tarim Craton:Passive or active?[J]. Lithos, 2012, 142/143:1-15. doi: 10.1016/j.lithos.2012.02.010
[15] Zong K Q, Zhang Z M, He Z Y, et al. Early Palaeozoic highpressure granulites from the Dunhuang block, northeastern Tarim Craton:constraints on continental collision in the southern Central Asian Orogenic Belt[J]. Journal of Metamorphic Geology, 2012, 30(8):753-768. doi: 10.1111/jmg.2012.30.issue-8
[16] He Z Y, Zhang Z M, Zong K Q, et al. Metamorphic p-T-t evolution of mafic HP granulites in the northeastern segment of the Tarim Craton (Dunhuang block):Evidence for early Paleozoic continental subduction[J]. Lithos, 2014, 196(5):1-13. http://www.sciencedirect.com/science/article/pii/S0024493714000760
[17] 王楠, 吴才来, 马昌前, 等.敦煌地块三危山地区花岗岩体地球化学, 锆石U-Pb定年及Hf同位素特征[J].地质学报, 2016, 90(10):2681-2705. doi: 10.3969/j.issn.0001-5717.2016.10.010
[18] Zhang J X, Yu S Y, Gong J H, et al. The latest NeoarcheanPaleoproterozoic evolution of the Dunhuang block, eastern Tarim craton, northwestern China:Evidence from zircon U-Pb dating and Hf isotopic analyses[J]. Precambrian Research, 2013, 226:21-42. doi: 10.1016/j.precamres.2012.11.014
[19] 辛后田, 赵凤清, 罗照华, 等.塔里木盆地东南缘阿克塔什塔格地区古元古代精细年代格架的建立及其地质意义[J].地质学报, 2011, 85(12):1977-1993. http://d.old.wanfangdata.com.cn/Periodical/dizhixb201112002
[20] 陈柏林, 杨屹, 王小凤, 等.阿尔金北缘大平沟金矿床成因[J].矿床地质, 2005, 24(2):168-178. doi: 10.3969/j.issn.0258-7106.2005.02.009
[21] 李月臣, 陈柏林, 陈正乐, 等.阿尔金北缘红柳沟-拉配泉一带铜金矿床硫同位素特征及其意义[J].地质力学学报, 2007, 13(2):131-140. doi: 10.3969/j.issn.1006-6616.2007.02.006
[22] 孟繁聪, 张建新, 相振群, 等.塔里木盆地东北缘敦煌群的形成和演化:锆石U-Pb年代学和Lu-Hf同位素证据[J].岩石学报, 2011, 27(1):59-76. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201101004
[23] 朱江, 吕新彪, 彭三国, 等.甘肃北山小西弓金矿区石英正长斑岩LA-ICP-MS锆石U-Pb年龄和地球化学特征[J].地质通报, 2015, 34(8):1460-1469. doi: 10.3969/j.issn.1671-2552.2015.08.006 http://dzhtb.cgs.cn/gbc/ch/reader/view_abstract.aspx?file_no=20150806&flag=1
[24] Jackson S E, Pearson N J, Griffin W L, et al. The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology[J]. Chemical Geology, 2004, 211(1):47-69. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=17d96cdc3a96b2aa4c52b4ebb0b5da26
[25] Van Achterbergh E, Ryan C G, Jackson S E, et al. Data reduction software for LA-ICP-MS in the Earth Sciences[J]. Mineralogical Association of Canada, 2001, 29:239-243. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=3861e59a4546c7a0b35d78f6e5f71b33
[26] Anderson T. Correction of common lead in U-Pb analyses that do not report 204Pb[J]. Chemical Geology, 2002, 192(1):59-79. http://www.sciencedirect.com/science/article/pii/S000925410200195X
[27] Ludwig K R. Mathematical-statistical treatment of data and errors for 230Th/U geochronology[J]. Reviews in Mineralogy and Geochemistry, 2003, 52(1):631-656. http://www.sciencedirect.com/science/article/pii/S0012821X0201107X
[28] Maniar P, Piccoli P. Tectonic discrimination of granitoids[J]. Geol. Soc. Amer. Bull., 1989, 101:635-643. doi: 10.1130/0016-7606(1989)101<0635:TDOG>2.3.CO;2
[29] Collins W J, Beams S D, White A J K, et al. Nature and origin of a type granites with articular reference to southeastern Australia[J]. Contrbutions to Mineralogy Petrology, 1982, 80:189-200. doi: 10.1007/BF00374895
[30] Sun S S, McDonough W F. Chemical and isotopic systematic of oceanic basalts: Implications for mantle composition and processes[C]//Saunders A D, Norry M J. Magmatism in the Ocean Basins.Geol. Soc. Special Publication, 1989, 42: 313-345.
[31] Pearce J A, Harris N B W, Tindle A G. Trance element discrimination diagrams for the tectonic interpretation of granitic rocks[J]. Journal of Petrology, 1984, 25:956-983. doi: 10.1093/petrology/25.4.956
[32] 吴福元, 李献华, 杨进辉, 等.花岗岩成因研究的若干问题[J].岩石学报, 2007, 23(6):1217-1254. doi: 10.3969/j.issn.1000-0569.2007.06.001
[33] 张旗, 李承东.花岗岩:地球动力学意义[M].青岛:海洋出版社, 2012:1-81.
[34] Whalen J B, Currie K L, Chappell B W. A-type granites:Geochemical characteristics, discrimination and Petrogenesis[J]. Contribution to Mineralogy and Petrology, 1987, 95(4):407-419. doi: 10.1007/BF00402202
[35] Defant M J, Drummond M S. Derivation of some modern arc magmas by melting of young subducted lithosphere[J]. Nature, 1990, 347:662-665. doi: 10.1038/347662a0
[36] 张旗, 王焰, 熊小林, 等.埃达克岩和花岗岩:挑战与机遇[M].北京:中国大地出版社, 2008.
[37] Sajona F G, Maury R C, Pubellier M, et al. Magmatic source enrichment by slab-derived melts in a young post-collision setting, central Mindanao (Philippines)[J]. Lithos, 2000, 54(3):173-206. http://d.old.wanfangdata.com.cn/NSTLQK/10.1016-S0024-4937(00)00019-0/
[38] Reagan M K, Gill J B. Coexisting calcalkaline and high-niobium basalts from Turrialba Volcano, Costa Rica:Implications for residual titanates in arc magma sources[J]. Journal of Geophysical Research:Solid Earth, 1989, 94(B4):4619-4633. doi: 10.1029/JB094iB04p04619
[39] Gao S, Rudnick R L, Yuan H L, et al. Recycling lower continental crust in the North China craton[J]. Nature, 2004, 432(7019):892-897. doi: 10.1038/nature03162
[40] Rapp R P, Shimizu N, Norman M D, et al. Reaction between slab-derived melts and peridotite in the mantle wedge:experimental constraints at 3.8GPa[J]. Chemical Geology, 1999, 160(4):335-356. doi: 10.1016/S0009-2541(99)00106-0
[41] 徐学义, 何世平, 王洪亮, 等.早古生代北秦岭-北祁连结合部构造格局的地层及构造岩浆事件约束[J].西北地质, 2008, 41(1):1-21. doi: 10.3969/j.issn.1009-6248.2008.01.001
[42] Batchelor R A, Bowden P. Petrogenetic interpretation of granitic rock series using multicationic parameters[J]. Chemical Geology, 1985, 48:43-55. doi: 10.1016/0009-2541(85)90034-8
[43] Jian P, Liu D Y, Kröner A, et al. Evolution of a Permian intraoceanic arc-trench system in the Solonker suture zone, Central Asian Orogenic Belt, China and Mongolia[J]. Lithos, 2010, 118(1):169-190. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=40ff8aa320c272880289a116d19525f3
[44] 冯继成, 张文, 吴泰然, 等.甘肃北山桥湾北花岗岩体的年代学、地球化学及其地质意义[J].北京大学学报(自然科学版), 2012, 481(1):61-70. http://d.wanfangdata.com.cn/Periodical_bjdxxb201201010.aspx
[45] 夏林圻, 李向民, 夏祖春, 等.天山石炭-二叠纪大火成岩省裂谷火山作用与地幔柱[J].西北地质, 2006, 39(1):1-49. doi: 10.3969/j.issn.1009-6248.2006.01.001
[46] 赵泽辉, 郭召杰, 韩宝福, 等.新疆三塘湖盆地古生代晚期火山岩地球化学特征及其构造-岩浆演化意义[J].岩石学报, 2006, 22(1):199-214. http://d.old.wanfangdata.com.cn/Periodical/ysxb98200601020
[47] Yang J H, Wu F Y, Wilde S A, et al. Tracing magma mixing in granite genesis:in situ U-Pb dating and Hf-isotope analysis of zircons[J]. Contrib. Mineral. Petrol., 2007, 153:177-190. http://www.tandfonline.com/servlet/linkout?suffix=CIT0084&dbid=16&doi=10.1080%2F00206814.2017.1375438&key=10.1007%2Fs00410-006-0139-7
-
图(11)
表(3)
计量
- 文章访问数: 691
- PDF下载数: 6
- 施引文献: 0