用户名: 密码: 验证码:
辽东古元古宙褶皱带变质角闪质岩石的流动与变形机制
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
中下地壳组成、结构与演化研究一直是地球科学研究中为人们关注的重要课题。作为中下地壳的重要组成,角闪石质岩石的流变性与力学表现直接制约着中下地壳的的属性与状态,影响着大陆岩石圈板块的表现。深入开展角闪石和角闪质岩石变形特点与变形机制的研究工作,将促进加深对于中下地壳岩石的蠕变规律与流变性的了解,进而建立完整和全面的地壳岩石圈力学和流变学结构模型。
    本文在野外地质调查与区域地质背景分析的基础上,重点应用光学显微分析、透射电镜分析、电子探针分析和变形形态组构计算机分析,以辽东古元古宙褶皱带高级变质角闪质岩石-斜长角闪岩中三种具有不同构造特点(片麻状、条带状和糜棱状)构造岩的显微构造分析为主,深入讨论了不同类型构造岩的岩石流动机制与变化规律,并结合前人开展的力学实验研究工作对于岩石圈力学与流变学结构进行了讨论。
    显微构造分析结果显示,具有不同构造特点的斜长角闪岩在很多方面有显著的差异。片麻状斜长角闪岩中角闪石的粒度粗大,呈短柱状,角闪石的轴比(短轴比长轴)在0.2~0.4之间,以0.3~0.4占优势;长石的延长性较低,但角闪石却具有明显的定向性,这说明岩石可能经历了一次不是很强的构造变形作用的改造。
    根据条带状斜长角闪岩中角闪石和斜长石的分异及定向性可以识别出主要由角闪石组成的劈理域和主要由长石组成的微劈石域组构。角闪石存在波状消光现象、晶体挠曲现象和长条形亚颗粒,亚颗粒的长轴平行于叶理方向。角闪石定向性比片麻状斜长角闪岩中角闪石定向性更为强烈,角闪石长轴在0~20°范围内密集分布;轴比集中在0.1~0.4之间。长石—角闪石边界为舌状且凸向角闪石,说明长石—角闪石边界的颗粒边界重结晶的边界移动方向为从长石向角闪石方向移动。长石具有弱的定向性,与叶理方向呈小角度相交,轴比在0.4~0.7之间。 糜棱状斜长角闪岩剪切变形强烈,变形特征明显,构成劈理域的角闪石定向性很强,组成糜棱叶理的主要矿物是斜长石和角闪石。角闪石的粒度在0.3~0.6 mm之间,轴比主要在0.1~0.2之间的高度集中,反映出角闪石单向延伸强烈。斜长石以个体形式存在,具有明显的定向性、大量的波状消光和亚颗粒,颗粒边界不规则,存在边缘细粒化,粒度集中在0.1~0.4 mm之间,轴比集中在0.2~0.5之间。长石具有强烈的定向性,斜长石的长轴集中于10°~35°之间,表明长石对叶理的形成起到了积极的促进作用。
    超微构造分析揭示出了角闪石矿物晶体内的位错结构及其组合形式。片麻状斜
    
    
    长角闪岩的晶格缺陷并不明显,仅局部可见少量的自由位错、环型位错、位错列、位错链和位错缠结。条带状斜长角闪岩的位错构造并不发育,只可见少数的位错构造,如环型位错和位错列;角闪石的毛发状超微构造比较普遍。和上述两种斜长角闪岩中的角闪石相比,糜棱状斜长角闪岩中的角闪石的超微构造现象比较丰富,出现的位错以自由位错和位错列为主。
    由电子探针对于角闪石和斜长石进行的成分分析及应用角闪石-斜长石地质温度计和角闪石地质压力计计算出三种不同构造类型的斜长角闪岩及其原岩的形成与变形温度-压力有着规律性的变化。原岩斜长角闪岩:P=2.94kbar;T=649.91℃;片麻状斜长角闪岩大约为P=5.34kbar;T=620.38℃;条带状斜长角闪岩大约为P=4.62kbar;T=644.95℃;糜棱状斜长角闪岩大约为P=5.12kbar;T=585.99℃。从温度和压力变化的趋势和规律,结合对原岩及三种构造岩显微构造特征分析认为,三种岩石类型是同一期变形不同阶段的产物。原岩斜长角闪岩形成于相对较低的压力和较高的温度环境中(早期伸展作用?)。在后期的变形和变质演化的递进过程中,相继出现了等温升压与其后的等压降温过程。这种过程最合理的解释,说明变形和变质作用发生于区域性收缩过程中。
    在递进变形作用过程中,塑性变形是斜长角闪岩流动和蠕变的主要形式,其中角闪石沿其平行于c轴各个方向的滑移作用普遍存在,尤其是条带状斜长角闪岩中的角闪石的变形机制出现了位错滑移的所有类型(平移滑移、双晶滑移和扭折);片麻状斜长角闪岩中的角闪石主要是晶体在定向重结晶作用下形成的;糜棱状斜长角闪岩中的角闪石是在动态重结晶和双晶滑移作用共同作用的结果。斜长石的变形机制以晶质塑性变形和超塑性流动两种机制为主。片麻状斜长角闪岩中的斜长石是动态重结晶作用和其后的恢复作用的结果;条带状斜长角闪岩中的斜长石是通过亚颗粒旋转动态重结晶形成的;糜棱状斜长角闪岩中的斜长石的变形机制是晶质塑性变形和超塑性流动作用。
    结合前人对于斜长角闪岩的实验变形研究结果,修正的大陆岩石圈结构模型中岩石圈强度从地壳的表层开始,随着深度的加大,具有多峰表现,而在地壳不同层次上,不同强度带之间并非简单的突变,更多情况下属于由岩石成分渐变导致的强度的递进变化。另一方面,从完全脆性的上部地壳向完全塑性的下部地壳之间的转变也并不是一个简单的过程,随着温度的升高、岩石中制约性矿物成分(石英、长石、角闪石、辉石)流变性的改变以及由此而致岩石流变学状态发生显著的转变,岩石的变形机制也在逐渐变化。
The composition, structure and evolution of the middle-lower crust has been an subject of extensive study in Earth sciences. Since amphibolites rocks constitute the major parts of the middle-lower crust, their rheological and mechanical behavior constrains the nature and state of latter, and therefore influences the evolution of continental plate. Detailed study on the deformation characteristics and deformation mechanisms of hornblende and hornblende rocks would promote understanding the creep laws and rheology of middle-lower continental crustal rocks, and establishing a comprehensive mechanical and rheological model of crustal lithosphere.
    This paper discusses about, from microstructural studies of three types of tectonites with different deformation characteristics (gneissic, banded and mylonitic structures) from high grade metamorphic amphibolites from the Paleoproterozoic Fold Belt in Liaodong Peninsula, the flow mechanisms of hornblende tectonites, on the basis of field geological investigation and analysis of geological settings, and by means of optical microstructural analysis, transmission electron microscope (TEM) analysis, electron microprobe analysis and digital shape fabric analysis. In combination with experiments preformed by Hacker, this thesis discusses the dynamic and rheological structure of the lithosphere.
    It is shown from microstructural analysis that amphibolites with different structural characteristics differ from each other distinctly in many aspects. Hornblende grains in gneissic amphibolites have a large grain size, short prism shape and their aspect ratios (short axis to long axis) between 0.2~0.4, with a maximum at about 0.3-0.4. Plagioclase grains are not strongly elongated, but hornblende grains have obvious crystallographic preferred orientation. It may suggest that the rocks have been transformed rather weakly during structural deformation.
    Cleavage domains mainly of hornblende grains and microlithons of plagioclase grains constitute the banded amphibolites. They result in differentiation and orientation of the hornblende and plagioclase grains in the amphibolites. Hornblende grains show undulose extinction, crenulation and strip subgrains with their long axes paralleling to foliation. The orientation of hornblende grains in banded amphibolites is much stronger than that in gneissic amphibolites. The orientations of long axes of the hornblende grains are centered between 0 and 20°. The grains have aspect ratios between 0.1 and 0.4. The hornblende-plagioclase contacts are amoeboid shaped, bulging into hornblende grains that indicate that direction of grain boundary migration toward hornblende grains during
    
    
    recrystallization. Plagioclase grains have weak orientation that intersect with foliation in rocks in a small angle. Their aspect ratios vary between 0.4~0.7. The mylonitic amphibolites experienced intensive shearing deformation and show obvious deformation characteristics. Hornblendes grains that make up the cleavage domains are strongly oriented. Both hornblende and plagioclase grains constitute mylonitic foliation. Hornblende grains have sizes varying from 0.3mm to 0.6mm and have aspect ratios highly concentrated between 0.1 and 0.2, indicating a strong unaxial extension. Plagioclase grains occur as single grains and are obviously oriented. There are lots evidences of deformation, as is undulose extinction, irregular grain boundaries, subgrains and boundary granulation. The grain sizes the plagioclase grains vary between 0.1mm and 0.4mm and have aspect ratios from 0.2 to 0.5. They are strongly oriented at 10°~35°in reference to the orientation of the direction of the thin sections, which imply that they may have contributed to the development of foliation in the rocks.
    Submicrostructural analysis revealed the dislocation substructures and dislocation associations. Minor amount of free dislocations, dislocation loops, dislocation arrays, dislocation chains and tangled dislocations are observed in hornblende grains from gneissic amphibolites. Dislocations are rare
引文
陈曼云,黄志安,辽宁大石桥-海城地区辽河群变泥质岩石的变质变形序列的研究.辽宁地质, 1994. (1-2):44-53
    陈荣度,辽东裂谷的地质构造演化.中国区域地质, 1990. (4):306-315
    董申保, 变质作用中的地质温压计. 山东地质,1990,6(1):16-25。
    甘盛飞,邱玉民,杨红英等.论糜棱岩的分类.现代地质,1994.8(1): 73-78.
    关会梅,刘俊来,张崧,张艳彬,深部地壳镁铁质岩石(斜长角闪岩)叶理的组成及形成机制分析——以辽东海城地区变质镁铁质岩石为例,世界地质,2003,22(4):344-351
    郭洪方, 吴春林, 吴桂云, 辽河群变质作用. 中国区域地质, 1989. (1):46-51
    何永年,林传勇,史兰斌,构造岩石学基础.北京:地质出版社,1988
    贺高品, 叶慧文,辽东-吉南地区早元古代两种类型变质作用及其构造意义.岩石学报, 1998.14(2):152-162
    胡玲,显微构造地质学概论.北京:地质出版社,1998.38-71
    穆克敏,常丽华,康维国,文明珠,孟庆丽,梁万通,透明矿物薄片鉴定(内部资料),1988,245-256
    靳是琴,成因矿物学概论.吉林:吉林大学出版社,1984. 117-119
    辽宁省地质矿产局,辽宁省区域地质志,中国地质出版社,1989.614-649
    刘劲鸿,角闪石成因矿物族及其应用.长春地质学院学报, 1986,(1):41-48
    刘俊来,岩石变形机制与流变学研究的近期发展. 地质科技情报。Vol.18 No.3 Sep.1999
    刘俊来, K. Weber, 上部地壳的流体作用与大理岩的低温塑性. 岩石学报,2000,16(4): 499-505
    刘瑞珣,显微构造地质学. 北京:北京大学出版社,1988.50-56
    刘喜山,李树勋,刘俊来,变形变质作用及成矿.北京:中国科学技术出版社, 1992.52-54
    刘永江,李三忠,白立新等,辽宁海城地区辽河群底部大型韧性滑脱带的构造演化.长春地质学院学报,1996.26(2):166-167
    刘永江,李三忠, 辽宁海城——大石桥——吉洞地区早元古花岗岩.辽宁地质,1996.(1):10-18
    刘正宏、徐仲元,糜棱岩显微构造研究.长春地质学院学报,1996.26(1): 20-28.
    李三忠,杨振升,刘永江,华北地台东部古元古构造格架.长春地质学院学报,1995.25(1): 14-21
    李三忠,杨振升,流褶层与韧变带研究.辽宁地质,1994.42:54-58
    李三忠,刘建忠, 变斑晶晶内显微构造特征及其成因综述.地质科技情报, 1997. 16(1): 46-52
    辽宁省地质矿产局.辽宁省区域地质志.北京:地质出版社, 1989.633-639
    
    刘永江,李三忠,杨振升,华北地台东缘早元古代隆-滑构造模式.地质论评, 1997,43(6):569-576
    卢良兆,徐学纯,刘福来, 中国北方早前寒武纪孔兹岩系.长春:长春出版社, 1996.195-218
    孙岩、朱文斌、郭继春,论糜棱岩研究. 高校地质学报,2001.7(4): 369-378.
    徐开礼,朱志澄,构造地质学(第二版).北京:地质出版社,1989,181-189
    徐仲元、刘正宏, 糜棱岩化作用和糜棱后重结晶作用.长春地质学院学报,1996.26(1): 96-103.
    许志琴,李海兵, 辽南地壳的收缩作用和伸展作用.地质论评,1991.37(3):122-135
    杨晓勇,杨学明,刘德良等,郯庐断裂带南段韧性剪切带糜棱岩化过程中长石成分和结构状态变化特征的研究.地震地质, 1998.20(4):332-342
    游振东,钟增球,汤中道等, 混合岩中斜长石的交代净边结构和倒转双晶研究。中国地质大学学报.Vol.21,No.5,Sep
    朴宽镐,吴家弘,唐淑兰, 辽东元古界宽旬群时代探讨.辽宁地质学报, 1982.(1):10-17
    王永锋,金振民, 岩石扩散蠕变及其地质意义.地质科技情报.Vol.20,No.4,Dec.2001
    肖成信,辽河群的退化变质. 辽宁地质, 1993. (2):189-193
    岳石,马瑞, 实验岩石变形与构造成岩成矿. 长春:吉林大学出版社,1990.pp 63-103
    张秋生.辽东半岛早期地壳与矿床.北京: 地质出版社, 1988.81-86
    赵光慧,郭泽君.辽宁东部地区早前寒武纪变质作用.见:董申保,沈其韩主编,中国变质地质图编制与研究论文集(第2辑).北京:地质出版社, 1988.79-90
    地矿部辽宁地质矿产勘察开发局,区域地质调查报告.北京:中国地质出版社, 1996. 56-63
    单文琅,宋鸿林,傅照人等,构造变形分析的理论方法和实践,武昌:中国地质大学出版社,1991.77-82
    王惠初,张一均,辽南早元古代花岗岩的变形温度及其构造意义.辽宁地质, 1993,(2):144-150
    王宗秀,唐哲民,杨中柱等,大连地区的中生代韧性构造变形,地震地质, 2000.22(4): 379-386.
    薛纪越,马军,丁阳,赵小宁,糜棱岩化作用中角闪石变形结构的透射电子显微镜研究,矿物岩石,1994,14(2):110-114
    许志琴,地壳变形与显微构造.北京:地质出版社,1984.
    张儒瑗,从柏林,矿物温度计和矿物压力计,北京:地质出版社,1983.150-198
    游振东,王正方,变质岩岩石学教程,武汉:中国地质大学出版社, 1988.125-162
    曾令森,李海兵,许志琴,辽南地壳韧性剪切变形中的分形及自组织. 地球学报,1996,17 (3),269-275
    钟增球,郭宝罗,构造岩与显微构造.北京:中国地质大学出版社,1991.
    朱志澄,构造地质学.北京:中国地质大学出版社,1999
    Allison, I. And La Tour, T. E., Brittle deformation of hornblende in a mylonite: a direct geometrical analogue of ductile deformation by translation gliding. Can. J. Earth Sci., 1977. 14: 1953-1958
    
    Anderson, J. L., Smith, D. R., The effects of temperature and for on the Al-in-hornblende barometer. Am. Mineral. 1995. 80:549-559
    Aranovich, L., Podlesskii, K., Geothermobarometry of high-grade metapelites: imultaneously operating reactions. In: Daly, J.S., Cliff, R.A., Yardley, B. W. D Eds., Evolution of Metamorphic. Belts Geol. Soc. Spec. Publ. 1989. 43, pp. 45–61.
    Adshead, N. S., Bell, T. H., The progressive development of a macroscopic upright fold pair during five near-orthogonal foliation-producing events: complex microstructures versus a simple macrostructure. Tectonophysics, 1999. 306:121-147
    Babai, H. A. and La Tour, T. E., Semibrittle and cataclastic deformation of hornblende-quartz rocks in a ductile shear zone. Tectonophysics, 1994, 229: 19-30
    Ball A, White S, An etching technique for revealing dislocation structure in deformed quartz grains. Tectonophysics, 1977. 37(4):T9 – T4
    Barruol, G., Kern, H., Seismic anisotropy and shear-wave splitting in lower-crustal and upper-mental rocks from the Ivrea Zone-experimental and calculated data. Physics of the earth and planetary interiors, 1996. 95: 175-194
    Bell, T. H., Foliation development-the contribution, geometry and significance of progressive, bulk, inhomogeneous shortening. Tectonophysics, 1981.75:273-296.
    Bell, T. H., Deformation partitioning and porphyroblast rotation in metamorphic rocks: a radical reinterpretation. J. Me&morph. Geol. 1985. 3:109-118.
    Berger, A, Stunitz, H., Deformation mechanisms and reaction of hornblende: examples from the Bergell tonalite (Central Alps). Tectonophysics, 1996. 257:149-174
    Berman, R. G., Mixing propertites of Ca Mg Fe Mn garnets. American Mineralogist, 1990, 75: 328-344.
    Biermann, C., (100) deformation twins in naturally deformed amphiboles. Nature, 1981. 292: 821-823
    Biermann, C., and Van Roermund H. L. M. , Defect structures in naturally deformed clinoamphiboles-a TEM study. Tectonophysics, 1993, 95: 267-278
    Blundy, J. D., Holland, T. J. B., Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer. Contrib. Mineral. Petrol. , 1990. 104:208-224
    Brodie, K H, Rutter, E H, On the relationship between deformation and metamorphism with special reference to the behaviour of basic rocks. In: Thompson A B, Rubie D C (Eds), Metamorphic Reactions: Kinetics, Textures, and Deformation. Advances in Phys Geochem 4, Berlin:Springer, 1985. pp: 138-179.
    Buck, P., Verformung von Hornblende-Einkristallen bei Drucken bis 21 kbar, Contrib. Mineral. Petrol., 1970. 28: 62-71
    Cumbest, R. J. and Drury, M. R., Roermund H. L. M., et al, Dynamic recrystallization and chemical
    
    
    evolution of clinoamphibole from Senja, Norway. Cintrib. Mineral. Petrol., 1989. 101:339-349.
    Deer, W. A., Howie, R. A. and Zussman, J., An Introduction to the Rock Forming Minerals. Longman, Harlow, 1992, 696pp
    DellAngelo, L. N., Tullis, J, Yund, R A. Transition from dislocation creep tomelt-enhanced diffusiom creep in fine-grainedgranitic aggregates. Tectonophtsics, 1987, 139(3/4): 325-332
    Dolinger, G. and Blacic, J. D.,Deformation mechanisms in experimentally and naturally deformed amphiboles, Earth Planet. Sci. Lett. , 1975, 26: 409-416
    Fernandez, A., Feybesse, J. L. & Mezure, J. F. Theoretical and experimental study of fabric developed by different shaped markers in two-dimensional simple shear. Bull. Sot. geol. Fr. 1983.25:319-326.
    Gapais, D.,Brun, J. P., A comparison of mineral grain fabrics and finite strain in amphibolites from eastern Finland. Can. J. Earth. Sci., 1981.18:995-1003
    Hdefonse, B, Lardeaux, J M, Caron, J M, The behavior of shape preferred orientations in metamorphic rocks: amphiboles and jadeites from the Monte Mucrone area (Sesia-Lanzo zone. Italian Western Alps), J. Struc. Geol.,1990.12:1005-1011
    Holland, T., Blundy, J., Non-ideal interactions in calcic amphiboles and their bearing on amphibole–plagioclase thermometry. Contrib. Mineral. Petrol. 1994.116:433-447.
    Jackson, J., Strength of the continental lithosphere : Time to abandon the jelly sandwich? GSA Today. 2002. September:4-9
    Jiang Z., Skrotzki W., Microstructure and texture of hornblende from an amphibolite of the KTB main borehole (NE-Bavaria).Z. Geol. Wiss., 1996.24:657 - 669
    Kern, H., Wenk, H. R., Experimental deformation of limestone-texture transitions and comparison of pure and simple shear. Terra Cognita. 1988.8; 1:67-68.
    Klepeis, K. A., Daczko, N. R., Clarke, G. L. Kinematic vorticity and tectonic significance of superposed mylonites in a major lower crustal shear zone, northern Fiordland, New Zealand. Journal of Structural Geology, 1999. 21: 1385-1405
    Kronenberg, A. K., Tullis, J., Flow strengths of quartz aggregates; grain size and pressure effects due to hydrolytic weakening. Journal of Geophysical Research. 1984. B. 89; 6:4281-4297.
    Kretz, R., Symbols for rock-forming minerals. Am. Mineral. 1983.68: 277-279
    Kruse, R, Stunite, H, Deformation mechanisms and phase distribution in mafic high-temperature mylonites from the Jotun Nappe, Southern Norway. Tectonophysics, 1999.303:223-249
    Liu Junlai, M. Shimada, Genesis of continental seismogenic zone and a new fault zone model.Chinese Science Bulletin . 2000. 45(20): 1886-1892
    Liu Xishan, Metamorphic Geology, Changchun: Jilin University Publishing House, 2001
    Naney, M. T., Phase equilibria of rock-forming ferromagnesian silicates in granitic systems. Am. J. Sci. 1983. 283: 993-1033.
    
    Passchier, C. W., Trouw R. A. J., Microtectonics. New York: Springer, 1996.69-81
    Platt, J. P., Progressive folding in ductile shear zones. J. Struct. Geol. 1983. 5: 619-622.
    Poirier, J. P. and Guillope. M., Deformation induced recrystallization of minerals. Bull. Mineral. , 1979.102: 67-71
    Rambere, H., & Ghosh, S. K., Rotation and strain of linear and planar structures in three-dimensional progressive deformation. Tectonophysics. 1977. 40, 309-337
    Ramsay, J. G., The geometry and mechanics of formation of ‘similar’ type folds. J. Geol. 1962.70, 309-327.
    Reinhardt, J., Kleeman, U., Extensional unroofing of granulitic lower crust and related low-presure, high temperature metamorphism in the Saxonian Granulite Massif, Germany. Tectonophysics. 1994.238, 71–94.
    Rooney, T. P. ,Riecker R.E., Experimental deformation of hornblende and amphibolite. EOS, 1969, 50: 332
    Rooney, T. P., Riecker R.E., Constant strain-rate deformation of amphibole minerals. Environ. Res. Pap., 1973. 430, AFCRL-TR-0045
    Rooney, T. P., Riecker R. E., and Gavasci A.T., Hornblende deformation features, Geology, 1975.3:364-366
    Sandiford, M., and Powell, R., Deep crustal metamorphism during continental extension: Modern and ancient example, 1986, Earth and planetary Science Letter, V.79: 151-158
    Schmidt, M., Amphibole composition in tonalite as a function of pressure: An experimental calibration of the Al-in hornblende barometer. Cintrib. Mineral. Petrol., 1992.110:304-310
    Schwerdtner, W. M., Pjreferred orientation of hornblende in a banded hornblende-gnerss. Am. J. Sci., 1964, 262: 1212-1229
    Shelley, D, Spider texture and amphibole preferred orientations. J. Struct. Geol.,1994.16: 709-717.
    Sills, J. D., Tarney, J., Petrogenesis and tectonic significance of amphibolites interlayered with metasedimentary gneisses in the Ivrea zone, Sourhern Alps, northwest Italy. Tectonophysics, 1984: 107-187
    Skjemaa, L., Rotation and deformation of randomly oriented planar and linear structures in progressive simple shear. J. Struct. Geol. 1980. 2: 101-109.
    Srivastava, P., Mitra, G. Deformation mechanisms and inverted thermal profile in the North Almora Thrust mylonite zone, Kumaon Lesser Himalaya, India. Journal of Structural Geology, 1996.18: 27-39
    Vauchez, A., Tommasi, A., Barruol, G., Rheological heterogeneity, mechanical anisotropy and deformation of the continental lithosphere. Tectonophysics. 1998. 296: 1-2: 61-86.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700