天宇铜镍矿床的岩相学、锆石U-Pb年代学、地球化学特征：对东疆镁铁-超镁铁质岩体源区和成因的制约
Lithological, chronological and geochemical characteristics of Tianyu Cu-Ni deposit: Constraints on source and genesis of mafic-ultramafic intrusions in eastern Xinjiang
-
摘要: 天宇镁铁-超镁铁质岩体位于新疆中天山地块与觉罗塔格构造带的分界断裂——沙泉子深大断裂的南侧约5km。岩体呈向北陡倾的岩墙状，地表出露面积约0.056km2。该杂岩体主要由辉长岩、辉石岩、辉橄岩和橄榄岩相组成，橄辉岩、辉橄岩和橄榄岩是主要的Cu、Ni赋矿岩相。镁铁-超镁铁岩的主量元素含量显示，天宇岩体属拉斑玄武岩成因系列，m/f为1.44~3.61，平均值为2.25，为铁质超基性岩（m/f=2~6.5）。稀土元素标准化配分模式为轻稀土富集型，Eu弱负异常或无异常，相似的稀土元素配分模式说明岩体的同源性。富集大离子亲石元素，亏损高场强元素Nb、Ta，说明源区可能有陆壳物质的混染。Nb/Hf、Ce/Pb、Nb/U、La/Sm、Th/Nb比值显示岩体可能经受上地壳物质的混染。锆石的LA-ICP-MS U-Pb年代学研究表明，岩体形成年龄为290.2±3.4Ma，与东天山地区镁铁-超镁铁质杂岩体的形成时间一致。锆石的Lu/Hf比值比较均一，且(176Hf/177Hf) i变化很小，说明源区性质比较单一。锆石的(176Hf/177Hf) i值为0.282625~0.282770，相应的εHf(t)均为正值（1.10~6.06），Lu-Hf的单阶段模式年龄（tDM1）为674~884.7Ma，平均年龄为799Ma，比岩体的U-Pb年龄大，显示岩浆来源于亏损地幔或者源区有壳源物质的加入。上述岩石地球化学、年代学特征，为晚古生代古亚洲洋向南俯冲提供了佐证。Abstract: Tianyu mafic-ultramafic intrusions are located in the south of the Shaquanzi deep-seated fault. Shaquanzi fault is the boundary between the Central Tianshan Massif and Jueluotage tectonic belt. It covers an area of 0.056km2in shape of dyke pitched to the north. The intrusions consist of gabbro, pyroxenite, olivine pyroxenite, pyroxene peridotite and peridotite. Olivine pyroxenite, pyroxene peridotite and peridotite are the main host rocks for the Cu-Ni ores. Major-element contents of Tianyu complex show tholeiitic evolution trend and m/f values range from 1.44 to 3.61 with 2.25 on average, falling into the range of ferrous-ultramafic rocks. Similar LREE-rich pattern and negative or no Eu anomaly indicate that Tianyu complex have the same magma source. Trace elements show LILE-rich and HFSE-depleted pattern. The depletion of Nb、Ta implies the contamination of continental material. Nb/Hf, Ce/Pb, Nb/U, La/Sm, Th/Nb values suggest the contamination of upper crust during upward of magma. Zircon LA-ICP-MS U-Pb dates yield 290.2± 3.4Ma which is consistent with the age of other mafic-ultramafic complex in East Tianshan. Uniform Lu/Hf values and the (176Hf/177Hf) i reveal that the characteristics of source are simple. The (176Hf/177Hf) i are in the range of 0.282625~0.282770 with corresponding εHf(t) values of 1.10~6.06. Lu-Hf single-stage modal ages (tDM1) vary from 674.0 to 884.7Ma, mean age（799Ma）is older than U-Pb age. These characteristics indicate that the parental magma derived from depleted mantle or had been contaminated by crustal material. These geochemical and chronological characteristics also constrain the southern subduction of Paleo-Asia Ocean in Paleozoic.
-
Key words:
- Tianyu /
- Cu-Ni deposit /
- Geochemistry /
- Zircon LA-ICP-MS U-Pb date /
- Lu-Hf isotope /
- Crust contamination /
- Eastern Xinjiang
-
-
[1] 新疆地矿局第六地质大队,新疆哈密市天宇镍矿普查报告,2007.
[2] 新疆地质矿产局第六地质大队,新疆哈密地区超基性岩调查报告,1994.
[3] Amelin Y,Lee DC,Halliday AN,Pidgeon RT,Nature of the Earth\'s earliest crust from hafnium isotopes in single detrital zircons,Nature,1999.
[4] Arndt NT,Christensen U,The role of lithospheric mantle in continental flood volcanism:Themal and geochemical constraints,Geophysical Resource,1992.
[5] Baldwin JA,Brown M,Schmitz MD,First application of titanium-in-zircon thermometry to ultrahigh-temperature metamorphism,Geology,2007(4).
[6] Barker JA,Menzies MA,Thirlwall MF,Macpherson CG,Implication and polybaric melt hybridization,Journal of Petrology,1997.
[7] Blichert-Toft J,Arndt NT,Gruau G,Hf isotopic measurements on Barberton komatiites:Effects of incomplete sample dissolution and importance for primary and secondary magamtic signatures,Chemical Geology,2004.
[8] Campbell IH,Griffiths RW,The evolution of mantle\'s chemical structure,Lithos,1993.
[9] 柴凤梅.张招崇.毛景文.董连慧.张作衡.叶会寿.吴华.莫新华 中天山白石泉镁铁-超镁铁质岩体岩石学与矿物学研究 [J].-岩石矿物学杂志2006(1)
[10] Chai FM,Zhang ZC,Mao JW,Dong LH Zhang ZH and Wu H,Geology,petrology and geochemistry of the Baishiquan Ni-Cu-bearing mafic-ultramafic intrusions in Xinjiang,NW China:Implications for tectonics and genesis of ores,Journal of Asian Earth Sciences,2008.
[11] 陈世平.王登红.屈文俊.陈郑辉.高晓理 新疆葫芦铜镍硫化物矿床的地质特征与成矿时代 [J].-新疆地质2005(3)
[12] Chen ZF,Cheng SD,Liang YH,Xu X,Opening-Closing Tectonics and Mineralization in Xinjiang,Urumqi:Xinjiang Science Technology and Hygiene Publishing House,1997.
[13] Claesson S,Vetrin V,Bayanova T,U-Pb zircon age from a Devonian carbonatite dyke,Kola peninsula,Russia:A record of geological evolution from the Arohaean to the Palaeozoic,Lithos,2000(1).
[14] Dai BZ,Jiang SY,Jiang YH,Zhao KD and Liu DY,Geochronology.geochemistry and Hf-Sr-Nd isotopic compositions of Huziyan mafic xenoliths,southern Hunan Province,Sonth China:Petrogenosis and implications for lower crust evolution,Lithos,2008.
[15] Griffin WL,Wang X,Jackson SE,Pearson NJ O-Reilly SY Xu XS and Zhou XM,Zircon chemistry and magma mixing,SE China:In-situ analysis of Hf isotopes,Tonglu and Pingtan igneous complexes,Lithos,2002.
[16] 韩宝福.何国琦.王式洸.洪大卫 新疆北部后碰撞幔源岩浆活动与陆壳纵向生长 [J].-地质论评1998(4)
[17] 韩宝福.季建清.宋彪.陈立辉.李宗怀 新疆喀拉通克和黄山东含铜镍矿镁铁-超镁铁杂岩体的SHRIMP锆石U-Pb年龄及其地质意义 [J].-科学通报2004(22)
[18] Hofmann W,Chemical difierentiation of the earth:The relationship between mantle,continental crust and oceanic crust,Earth and Planetary Science Letters,1988.
[19] 姜常义.程松林.叶书锋.夏明哲.姜寒冰.代玉财 新疆北山地区中坡山北镁铁质岩体岩石地球化学与岩石成因 [J].-岩石学报2006(1)
[20] Lesher CM,Campbell IH,Geochemical and fluid-dynamic modelling of compositional variations in Archean komatiite-hosted nickel-sulfide ores in Western Australia,Economic Geology,1993.
[21] Li CS,Naldrett AJ,Ripley EM,Critical factor for the formation of a nickel-copper deposit in an evolved magma system:Lessons from a comparison of the Pants Lake and Voisey\'s Bay sulfide occurronces in Labrador,Canada,Mineralium Deposits,2001.
[22] Li HQ,Xie CF,Chang HL,Study on Metallogenetic Chronology of Nonferrous and Precious Metallie Ore Deposits in North Xinjiang,China,北京:地质出版社,1998.
[23] Li JL,Tectonic relationship between the Junggar residual back-arc basin and Tianshan orogenic zone,Acta Sedimentologica Sinica,1989(zk).
[24] 李金祥.秦克章.徐兴旺.孙赫.程松林.吴华.莫新华 新疆东天山白石泉Cu-Ni硫化物矿床杂岩体的地球化学特征及其对矿床成因和构造背景的制约 [J].-矿床地质2007(1)
[25] 李月臣.赵国春.屈文俊.潘成泽.毛启贵.杜安道 新疆香山铜镍硫化物矿床Re-Os同位素测定 [J].-岩石学报2006(1)
[26] Ma RS,Wang CY,Ye SF,Tectonic framework and crustal evolution of eastern Tianshan mountains,南京:南京大学出版社,1993.
[27] 毛景文.杨建民.屈文俊.杜安道.王志良.韩春明 新疆黄山东铜镍硫化物矿床Re-Os同位素测定及其地球动力学意义 [J].-矿床地质2002(4)
[28] 毛启贵.肖文交.韩春明.孙敏.袁超.闫臻.李继亮.雍拥.张继恩 新疆东天山白石泉铜镍矿床基性-超基性岩体锆石U-Pb同位素年龄、地球化学特征及其对古亚洲洋闭合时限的制约 [J].-岩石学报2006(1)
[29] Mecdonald R,Rogers NW,Fitton JG,Plume lithosphere interactions in the generation of the basalts of the Kenys rift,East Africa,Journal of Petrology,2001.
[30] Pidgen RT,Nemchin AA,Hitchen GJ,Internal structures of zircons from Archaena granites from the Darling Range batholith:Implicalions for zircon stability and the interpretation of zircon U-Pb age,Contributions to Mineralogy & Petrology,1998(3).
[31] Qin KZ,Sun S,Chen HH,Hao J,Temporal-spatial distribution framework of metal deposits in northern Xinjiang:Guides of Paleozoic archjpelago-style collision orogenic belts,北京:海洋出版社,1999.
[32] Qin KL,Paleozoic Central-Asia orogeneses and metallogenese in Northern Xinjiang,Beijing:Institute of Geology and Geophysics,CAS,2000.
[33] 秦克章.方同辉.王书来.朱宝清.冯益民.于海峰.修群业 东天山板块构造分区、演化与成矿地质背景研究 [J].-新疆地质2002(4)
[34] Qin KZ,Zhang LC,Xiao WJ,Overview of major Au,Cu,Ni and Fe deposits and metallogenic evolution of the eastern Tianshan Mountains,Northwestern China,London,2003.
[35] 秦克章.丁奎首.许英霞.孙赫.徐兴旺.唐冬梅.毛骞 东天山图拉尔根、白石泉铜镍钴矿床钴、镍赋存状态及原岩含矿性研究 [J].-矿床地质2007(1)
[36] Ripley EM,Systematics of sulphur and oxygen isotopes in rustic igneous rocks and related Cu-Ni-PGE mineralization,1999.
[37] 芮宗瑶.王龙生.王义天.刘玉琳 东天山土屋和延东斑岩铜矿床时代讨论 [J].-矿床地质2002(1)
[38] Scherer EE,Cameron KL,Blichert-Toft J,Lu-Hf garnet geochronology:Closure temperature relative to the Sm-Nd system and the effects of trace mineral inclusions,Geochimica et Cosmochimica Acta,2000.
[39] Shen WZ,Isotope Geology,北京:原子能出版社,1997.
[40] Soderlund U,Patchett PJ,Vervoort JD,Isachsen CE,The I76Lu decay constant detennined hv Lu-Hf and U-Pb isotope systematics of Precambrian mafic intrusion,Earth and Planetary Science Letters,2004.
[41] Su BX,Qin KZ,SUN H,Tang DM Xiao QH and Cao MJ,Petrological and mineralogical characteristics of Hongshishan complex in Beishan area,Xinjiang:Implications for assimilation and fractional crystallization,Acta Petrologica Sinica,2009(4).
[42] 孙赫.秦克章.李金祥.徐兴旺.三金柱.丁奎首.惠卫东.许英霞 东天山图拉尔根铜镍钴硫化物矿床岩相、岩石地球化学特征及其形成的构造背景 [J].-中国地质2006(3)
[43] 孙赫.秦克章.徐兴旺.李金祥.丁奎首.许英霞.三金柱 东天山镁铁质-超镁铁质岩带岩石特征及铜镍成矿作用 [J].-矿床地质2007(1)
[44] Sun SS,McDonough WF,Chemical and isotopic systematics of oceanic basalts:Implications for mantle composition and processes,Geological Society of London,Special Publication,1989.
[45] Sun WD,Hu YH,Kamenetsky VS,Eggins SM Chen M and Arculus RJ,Constancy of Nb/U in the mantle revisited,Geochimica et Cosmochimica Acta,2008.
[46] Taylor SR,Mclennan SM,The Continental Crust:Its Composition and Evolution,Oxford:Blackwell Publishers Inc,1985.
[47] Wang H,Qu WJ,Li HQ,Chen SP,Dating and discussion on the rock-forming and ore-forming age of newly-discovered Cu-Ni sulfide deposits in Hami,Xinjiang,Acts Geologica Sinica,2007(1).
[48] Wu FY,Sun DY,Li HM,A-type granites in northeastern China:Age and geochemical constraints on their petrogenesis,Chemical Geology,2002(1-2).
[49] Wu FY,YangYH,Xie LW,Yang JH and Xu P,Hf isotopic compositions of the standard zircons and baddeleyites used in U-Pb geochronology,Chemical Geology,2006.
[50] 吴华.李华芹.莫新华.陈富文.路远发.梅玉萍.邓岗 新疆哈密白石泉铜镍矿区基性-超基性岩的形成时代及其地质意义 [J].-地质学报2005(4)
[51] Xiao WJ,Zhang LC,Qin KZ,Sun S and Li JL,Paleozoic accretionary and collisional tectonics of the eastern Tianshan(China):Implications for the continental growth of central Asia,American Journal of Science,2004.
[52] Xu MX,Li ZO,Discussion of petrographic characteristics and origin of Huangshannan ore-bearing mafic-ultramafic complexe,in Hami,Xinjiang,Journal of Chengdu College of Geology,1992(1).
[53] Xu XW,Ma TL,Sun LQ,Cai XP,Characteristics and dynamic origin of the large-scale jiaoluotage ductile compressional zone in the eastern Tianshan Mountains,Structural Geology,2003.
[54] Yang XK,Ji JS,Luo GC,Tao HX,Plate tectonic and forming law of the metallic ore deposits in eastern Tianshan,Journal of Xi\'an Geology College,1997(3).
[55] Zhang LC,Wu NY,Geological structures and evolution history of Tianshan Mts,Xinjiang Geology,1985(3).
[56] Zheng YF,Zhao ZF,Wu YB,Zircon U-Pb age.Hf and O isotope constraints on protolith origin of ultrahigh-pressure eclogite and gneiss in the Dabie orogen,Chemical Geology,2006.
[57] 郑永飞.陈仁旭.张少兵.唐俊.赵子福.吴元保 大别山超高压榴辉岩和花岗片麻岩中锆石Lu-Hf同位素研究 [J].-岩石学报2007(2)
[58] Zhou JY,Mao YS,Huang ZX,Volcanic Geology of Palaeocontinel Margin in East Tianshan Mts,成都:成都科技大学出版社,1994.
[59] Zhou MF,Lesher CM,Yang ZX,Li JW and Sun M,Geochemistry and Petrogenesis of 270 Ma Ni-Cu-(PGE)sulfide-bearing mafic intrusions In the Huangshan district,eastern Xinjiang,Northwest China:Implications for the tectonic evolution of the Central Asian orogenic belt,Chemical Geology,2004.
[60] 柴凤梅.张招崇.毛景文.董连慧.张作衡.叶会寿.吴华.莫新华 中天山白石泉镁铁-超镁铁质岩体岩石学与矿物学研究 [J].-岩石矿物学杂志2006(1)
-
计量
- 文章访问数:
- PDF下载数:
- 施引文献: 0
下载: