碳酸岩的地质地球化学特征及其大地构造意义

doi:10.11867/j.issn.1001-8166.1998.05.0457

地球科学进展 ›› 1998, Vol. 13 ›› Issue (5): 457 -466. doi: 10.11867/j.issn.1001-8166.1998.05.0457

杨学明 ^1,2，杨晓勇 ^1,2，Ｍ.Ｊ.Le Bas ³

1.中国科技大学地球和空间科学系合肥 230026；2.第三世界科学院中国科学技术大学地球科学和天文学高级研究中心合肥 230026；3.Department of Geology, University of Leicester, Leicester LEI 7RH, U. K.

收稿日期:1997-12-19 修回日期:1998-05-29 出版日期:1998-10-01
通讯作者: 杨学明
基金资助:
中国科学院留学经费择优支持回国工作基金、国家教委科研基金和中国科技大学青年科学基金资助。

GEOLOGICAL AND GEOCHEMICAL CHARACTERISTICS OF CARBONATITES AND THEIR IMPLICATION FOR TECTONIC SETTINGS

Yang Xueming ^1,2,Yang Xiaoyong ^1,2,M. J. Le Bas ³

1.Department of Earth and Space Sciences, University of Science and T chnology of China, Hefei 230026; 2.The Advanced Research Center for Earth Science and Astronomy, The Third World Academy of Science, USTC, Heifei 230026; 3.Department of Geology, University of Leicester, Leicester LE1 7RH, U. K.

Received:1997-12-19 Revised:1998-05-29 Online:1998-10-01 Published:1998-10-01

下载PDF ( 1315 )

从已知碳酸岩的地质产状、岩石学特征、Nd-Sr-Pb-O-C同位素及痕量元素地球化学特征数据，结合高温高压实验岩石学资料，论述了其地幔源区的物质成分、交代过程软流圈地幔部分熔融机制和碳酸岩岩浆的演化模型。碳酸岩既可以产生于拉张岩石圈构造背景，也能够产生于挤压而派生的引张岩石圈构造背景。前者以产于裂谷环境、与硅酸不饱和过碱性岩构成环状碳酸岩—碱性杂岩为特征，主要由起源于软流圈地幔的霞石质超基性—基性岩浆经液态不混溶作用而形成；后者产于碰撞造山过程中派生的引张岩石圈断裂带，以单一的透镜状、条带状和似层状碳酸岩体为标志，直接由导源岩石圈富集地幔的低程度部分熔融作用而产生的碳酸岩浆侵入或喷发所形成。

关键词: 碳酸岩, 霓长岩, 同位素和痕量元素地球化学, 岩石圈引张构造环境, 地幔交代作用, 热地幔柱

This contribution reviews on the chemical compositions of the mantle sources of carbonatites, mantle metasomatism, mechanisms of partical melting in asthemospheric mantle and the evolution models for carbonatite magmas based on the occurrences, petrologic characteristics and Nd-Sr-Pb isotope and trace element data of the known carbonatites in the world and experiment petrologic data. Carbonatite could not only be produced in extentional tectonic setting in lithosphere, such as continental rift, but also be formed in locally derivative spreading setting on a compressive tectonic background. The former is characterized by association with peralkaline rocks forming ring complexes and mainly is derived from the asthenospheric mantle as a nephelinitic ultrabasicbasic magmas and then through liquid immicibility, but the later is characterized by its occurrence as a single lens and banded carbonatitic intrusion and/or extrusion along extentional lithospheric fractures resulted from continental collsion and in such case carbonatite could directly be produced by very small partial melting of the lithospheric mantle.
There are three cabonatite origin processes that probably happen above a mantle plume or different parts of a mantle plume, which are not mutually exclusive.①Partial melting of CO₂saturated asthenoshere mantle atca. 100 km depth to produce Na-Mg-rich carbonatite magma,no associated silicate rocks.②Fractional crystallization of carbonate-bearing undersaturated silicate magmas(nephelinitic/melilititic) produced by partial melting of sthenospheric mantle at intersection of the geotherm with a volatile-poor solidus. ③Liquid immiscibility of a carbonaterich silicate magma(nephelinitc/ melilititic) produced by partial melting of asthenosheric mantle at intersection of the geothern with a volatile-richer solidus.

Key words: Carbonatite, Fenite, Isotope and trace element geochemistry, Extentional tectonic setting in lithosphere, Mantle metasomatism, Plume.

中图分类号:

[1] Le Bas Mj. Carbonatite-Nepheiinite Volcanism. London: Sons & Wiley, 1977.
[2] Bell K, Keller J, ed. Carbonatite Volcanism: Oldoinyo Lengai and Petrogenesis of Natrocarbonatites genesis.Berlin: Springer-Verlag, 1995.
[3] Bailey D K. Carbonatite magmas. J Geol Soc London, 1993, 150: 637-651.
[4] Dobson D P, Jones A P. In-situ measurement of viscosity and density of carbonate melts at high pressure. Earth Planet Sci Lett, 1996, 143: 207-215.
[5] Triman A H, Schedl A. Properties of carbonatite magma and processes in carbonatite magma chambers. J Petrol, 1983, 91:437-447.
[6] Sweeney R. Carbonatite melt compositions in the earth ps mantle. Earth Planet Sci Lett, 1994, 128: 259-290.
[7] Wooly A R, Kempe D R C. Carbonatites: nomenclature, average chemical compositions, and element distribution. In: Bell Ked. Carbonatites: Genesis and Evolution. London: Unwin Hyman, 1989. 1-14.
[8] Wooly A R. The spatial and tem poral distribution of carbonatites.In: BellK, ed. Carbonatites: Genesis and Evolution. London: Unwin Hyman, 1989.15-37
[9] Le Bas M J . Carbonat it e m agmas. M ineral M abg, 1981, 44: 133- 140.
[10] Le Bas M J. Diversification of carbonatites. In: Bell K, ed. Carbonatites. London: Unwin Hyman, 1989. 427-447.
[11] Mian I, Le Bas M J. The biotite-phlogopite series in sodic fenites from the Loe Shilman Carbonatite complex, NW Parkistan.Mineral Mag, 1987,51:397-408.
[12] Mian I, Le Bas M J. Sodic amphiboles in fenites from the Loe Shilman carbonatite complex, NW Pakistan. Mineral Mag, 1986, 50:187-197.
[13] Le Bas M J. Oceanic carbonatite. In: Kornprobst J, ed. Kimberlite 1: Kimberlite and Related Rocks. Amsterdam: Elsevier, 1984. 169-178.
[14] Church A A, Jones A P. Silicate-carbonatite immiscibility at Oldoinyo Lengai. J Petrol, 1995, 36: 869-889.
[15] Bell K, Simonetti A. Carbonatite magmatism and plume activity: implications from Nd, Pb and Sr isotope systematics of Oldoinyo Lengai. J Petrol, 1996, 37: 1 321-1 339.
[16] Dawson J B, Pinkerton H June 1993 eruption of Oldoinyo Lengai, Tanizania: exceptionally viscous and large carbonatite lava flows and evidence for coexisting sillicate and carbonatite magmas. Geology, 1994, 22: 709-802.
[17] Green D H, Wallace M E. Mantle metasonmatism by ephemeral carbonatite melts. Natrue, 1988, 336: 459-462.
[18] Wallace M E, Green D H.An experimental determination of primary carbonatite composition.Nature, 1988, 335: 343-346.
[19] Wyllie P J, Huang W-L. Carbonation and melting reactions in the system CaO-MgO-SiO₂-CO₂ at mantle pressures with geophysical and petrological applications. Contrib Mineral Petrol, 1976, 54: 79-107.
[20] Yaxley G M, Green D H. Experimental reconstruction of sodic dolomitic carbonatite melts from metasomatised lithosphere. Contrib Mineral Petrol, 1996, 124: 359-369.
[21] Pearce N J G, Leng M J. The orgian of carbonatites and related rocks from the Igaliko Dyaliko Dyke Swarm, Gardar Province, South Greenland: field, geochemical and C-O-Sr-Nd iostope evidence. Lithos, 1996, 39: 21-40.
[22] Nelson D R, Chivas A R, Chapell B W, et al. Geochemical and isotopic systematics and implications for the evoltuion of oceaisland sources. Geochim Cosmochim Acta, 1988, 52: 1-17.
[23] Phipotts J, Tatsumotoo M, Li X, et al. Some Nd and Sr isotopic systematics for the REE-enriched deposit at Bayan Obo,China. Chem Geol, 1991, 90: 177-188.
[24] Roden M F, Murthy R V, Gaspar J C. Sr and Nd isotopic composition of the Jacupiranga carbonatite. J Geol, 1985, 93: 212-220.
[25] Allegre C J. Isotope geodynamics. Earth Planet Sci Lett, 1987, 86:175-203.
[26] Hart S R. A large-Scale isotope anomaly in the Southern hemisphere mantle. Nature, 1984, 309: 753-757.
[27] Saunders A D, Norry M J, Tarney J. Origin of MORB and chemically depleted mantle reservoirs: trace element constraints. J Petrol, 1988, Special Lithosphere issue: 425-445.
[28] Chaffery D J, Cliff R A, Wilson B M. Characterization of the St Helena magma source. In: Saunders A D, Norry M J, eds. Magmatism in Ocean Basins. Spec Publ Geol Soc, 1989, (42): 257-276.
[29] Gerlach D C, Cliff R A, Davies G R, et al. Magma Sources of the Cape Verdesarchipelago: isotopic and trace element contraints. Geochim Cosmochim Acta, 1988, 52: 2 979-2 992.
[30] Piccirillo E M, Civetta L. Regional variations within the Parana flood basalts(southern Brazil): evidence for subcontinental mantle heterogeneity and cruustal contamination. Chem Geol, 1989, 75: 103-122.
[31] Cliff R A. Isotopic dating in metamorphic belts. J Geol Soc Lond, 1985, 142: 97-110.
[32] Storey M, Saunders A D, Tarney J, et al. Geochemical evidence for plume-mantle interactions beneath Kergulen and Herd Islands, Indian Ocean. Nature, 1988, 336: 371-374.
[33] Stille P, Unruh D M, Tatsumoto M. Pb, Sr, Nd and Hf isotopic evidence of multiple sources for Oahu, Hawwii basalts. Nature, 1983, 304: 25-29.
[34] Fittion J G, James D, Kempton P D, et al. The role of the lithospheric mantle in the generation of late Cenozoic basic magmas in the western United States. J Petrol, 1988, Special Lithosphere issue: 331- 349.
[35] Menzies M A, Halliday A. Lithospheric domains beneath the Archaean and Proterozoic crust of Scotland. J Petrol, 1988,Special Lithosphere issue: 275-302.
[36] Song Y, Frey F A. Geochemistry of peridotite xenoliths in basalts from Hannuoba, eastern China: implications for sub-continental mantle heterogeneity. Geochim Cosmochim Acta, 1989, 53: 97-114.
[37] Downes H, Dupuy C. Textural, isotopic and REE variations in spinel peridotite xenoliths, Massif central, France. Earth Planet Sci Lett, 1987, 82: 121-135.
[38] Vance D, Stone J O H, O'Nions R K. He, Sr and Nd isotopes in xenoliths from Hawaii and other oceanic islands. Earth Plantet Sci Lett, 1989, 86:147-160.
[39] Weaver B L. The origin of ocean island basalt end-member compositions: trace element and isotopic constraints. Earth Planet Sci Lett, 1991, 104:3810.
[40] McCulloch M T, Japues A, Nelson D R, et al. Nd and Sr isotopes in kimberlites and lamproites from western Australia: an enriched mantle origin. Nature, 1983, 302: 400- 403
[41] Kramers J D, Smith C B, Lock N P, et al. Can Kimberlites be generated from ordinary mantle? Nature, 1981, 291: 53-56.
[42] Zinler A, Hart S R. Chemical geodynamics. Ann Rev Earth Planet Sci, 1986, 14: 493-571.
[43] Deines P. Stable isotope variations in carbonatites. In: Bell K, ed. Carbonatites: Genesis and Evolution London: Unw in Hyman, 1989, 301-359.
[44] Le Bas M J, Spiro B, Yang Xueming. Oxygen, carbon and strontium isotope study of the carbonatitic dolomite host of the Bayan Obo Fe-Nb-REE deposit, Inner Mongolia, N China. Mineral M ag, 1997, 61: 531-541.
[45] Kalt A, Hegner E, Satir M. Nd, Sr, and Pb isotopic evidence for diverse lithospheric mantle sources of East African Rift carbonatites. Tectonophysics, 1997, 278: 31-45.
[46] Le Bas M J, Yang Xueming, Zhang Peishan, et al. Geochemical characteristics of the Bayan Obo REE-Nb-Fe carbonatitic complex, Inner Mongolia, N. China. Abstract of 30th IGC, 1996, 2: 390. Beijing, 4-14 August, 1996.
[47] Veizer J. Trace elements and isotopes in sedimentary carbonates. Mineral Rev, 1983, 11: 265-199.

[1]	秦朝建，裘愉卓. 岩浆（型）碳酸岩研究进展[J]. 地球科学进展, 2001, 16(4): 501-507.
[2]	王岳军,韩吟文,郑海飞. 地幔地球化学研究综述[J]. 地球科学进展, 1995, 10(6): 572-576.
[3]	曹荣龙,朱寿华. 地幔流体与成矿作用[J]. 地球科学进展, 1995, 10(4): 323-329.
[4]	喻学惠. 地幔交代作用：研究进展、问题及对策[J]. 地球科学进展, 1995, 10(4): 330-335.

阅读次数

全文

摘要