内蒙古索伦山地区蛇绿岩岩石单元地质特征、就位机制及时限
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摘要
内蒙古索伦山地区出露蛇绿岩,其研究对探讨古亚洲洋演化具有重要意义。对内蒙古索伦山地区蛇绿岩进行了系统的调查和研究,探讨了其就位机制与时限。结合索伦山蛇绿岩地质特征和区域地质背景综合分析,认为研究区蛇绿岩组合包括地幔与洋壳组分。索伦山地区蛇绿岩存在较为完整的蛇绿岩组合模式,出露地幔岩石组合为蛇纹石化纯橄榄岩、蛇纹石化二辉-方辉橄榄岩、橄榄辉石岩和硅化碳酸盐化蚀变超基性岩(风化壳)等。蛇绿岩组合中洋壳组分为辉长岩、辉绿岩、玄武岩和硅质岩。蛇绿岩就位机制划分为4种,即碰撞仰冲型、增生底垫型、俯冲剥离型和角流型。其中,俯冲剥离型就位机制表现为岩石组合齐全完整的特征,产出形态为岩块、岩片,其中岩块、岩片与基质为构造断层接触;在俯冲带近大陆一侧常形成岛弧岩浆岩等特征。索伦山蛇绿岩地质特征与俯冲剥离型就位机制特征完全相符,故索伦山蛇绿岩就位机制大致为洋中脊俯冲剥离型。根据大洋岩石圈形成之后在10 Ma之内就位这一原则,结合索伦山地区辉长岩SHRIMP锆石U-Pb年龄为(280.7±5.3)Ma,认为索伦山蛇绿岩就位时限在270 Ma左右。
The ophiolites in Solonker zone,Inner Mongolia is of significance on evolution of the Paleo-Asian Ocean. The ophiolites from the study area have been investigated and studied systematically on petrology. On that basis,emplacement mechanisms and timing of the Solonker zone ophiolites were discussed. Combined with analyses of the geological and tectonic characteristics of the ophiolites from Solonker,we concluded that the ophiolites consist of compositions of both mantle and oceanic crust. There are a relatively complete sequence of the ophiolite in Solonker zone. In Solonker zone,mantle rocks are composed of serpentinized dunite,serpentinized lherzolite,serpentinized harzburgite,olivine pyroxenite and silicified,carbonated metamorphic ultrabasic rock( weathering crust) and so on. Oceanic crust rocks are composed of gabbro,diabase,basalt and chert. The ophiolites occur in the form of tectonic slices and blocks. The contact relationship between the ophiolites and adjacent geological body rocks is fault contact. Based on different proeesses and characteristics,four mechanisms of ophiolite emplacement are mainly discussed: collision-obduction type,accretion-underplating type,subduction-flake type,and corner flow type. Among the four mechanisms,the characteristics of subduction-flake typeophiolite emplacement mechanisms are as the following: sequence in rock associations of ophiolite is complete;the ophiolites emerge in the form of tectonic slices and blocks; the contact relationship between tectonic slices,blocks and matrix is fault contact; arc magmatic rocks occur in the subducting belts next to continent and so on.Geological characteristics of the ophiolites from Solonker conform basically with the characteristics of subductionflake type ophiolite emplacement mechanisms. Emplacement mechanism of ophiolites in the Solonker zone is mainly subduction-flake of mid-ocean ridge type. Since ophiolites emplacement occur in 10 Ma after forming oceanic lithosphere and the SHRIMP U-Pb age dating of zircons from the gabbro of ophiolite is( 280. 7 ± 5. 3)Ma,emplacement timing of the ophiolites in Solonker zone is 270 Ma or so.
The ophiolites in Solonker zone,Inner Mongolia is of significance on evolution of the Paleo-Asian Ocean. The ophiolites from the study area have been investigated and studied systematically on petrology. On that basis,emplacement mechanisms and timing of the Solonker zone ophiolites were discussed. Combined with analyses of the geological and tectonic characteristics of the ophiolites from Solonker,we concluded that the ophiolites consist of compositions of both mantle and oceanic crust. There are a relatively complete sequence of the ophiolite in Solonker zone. In Solonker zone,mantle rocks are composed of serpentinized dunite,serpentinized lherzolite,serpentinized harzburgite,olivine pyroxenite and silicified,carbonated metamorphic ultrabasic rock( weathering crust) and so on. Oceanic crust rocks are composed of gabbro,diabase,basalt and chert. The ophiolites occur in the form of tectonic slices and blocks. The contact relationship between the ophiolites and adjacent geological body rocks is fault contact. Based on different proeesses and characteristics,four mechanisms of ophiolite emplacement are mainly discussed: collision-obduction type,accretion-underplating type,subduction-flake type,and corner flow type. Among the four mechanisms,the characteristics of subduction-flake typeophiolite emplacement mechanisms are as the following: sequence in rock associations of ophiolite is complete;the ophiolites emerge in the form of tectonic slices and blocks; the contact relationship between tectonic slices,blocks and matrix is fault contact; arc magmatic rocks occur in the subducting belts next to continent and so on.Geological characteristics of the ophiolites from Solonker conform basically with the characteristics of subductionflake type ophiolite emplacement mechanisms. Emplacement mechanism of ophiolites in the Solonker zone is mainly subduction-flake of mid-ocean ridge type. Since ophiolites emplacement occur in 10 Ma after forming oceanic lithosphere and the SHRIMP U-Pb age dating of zircons from the gabbro of ophiolite is( 280. 7 ± 5. 3)Ma,emplacement timing of the ophiolites in Solonker zone is 270 Ma or so.
引文
[1]DILEK Y.Ophiolite concept and its evolution[M]//DILEK Y,NEWEOMB S.Ophiolite Concept and the Evolution of Geological Thought.Boulder:Geological Society of America,2003:1-16.
[2]DILEK Y,FURNES H.Ophiolite genesis and global tectonics:Geochemical and tectonic fingerprinting of ancient oceanic lithosphere[J].Geological Society of America Bulletin,2011,123(3/4):387-411.
[3]DILEK Y,FURNES H.Ophiolites and their origins[J].Elements,2014,10(2):93-100.
[4]HAWKINS J W.Geology of supra-subduction zone:Implications for the origin of ophiolites[M]//DILEK Y,NEWEOMB S.Ophiolite Concept and the Evolution of Geological Thought.Boulder:Geological Society of America,2003:227-268.
[5]张旗,周国庆.中国蛇绿岩[M].北京:地质出版社,2001:1-15.
[6]DILEK Y.Ophiolite pulses,mantle plumes and orogeny[M]//DILEK Y,NEWCOMB S.Ophiolites in Earth History.London:Geological Society,2003:9-19.
[7]SENGOR A M C,NATAL'IN B A,BURTMAN V S.Evolution of the Altaid tectonic collage and Paleozoic crustal growth in Eurasia[J].Nature,1993,364:299-307.
[8]SENGOR A M C,NATAL'IN B A.Paleotectonics of Asia:fragments of a synthesis[M]//YIN A,HARRISON M.The Tectonic Evolution of Asia.Cambridge:Cambridge University Press,1996:486-460.
[9]LI J Y.Permian geodynamic setting of Northeast China and adjacent regions:Closure of the Paleo-Asian Ocean and subduction of the Paleo-Pacific Plate[J].Asian Earth Science,2006:26(3/4):207-224.
[10]肖文交,舒良树,高俊,等.中亚造山带大陆动力学过程与成矿作用[J].新疆地质,2008,26(1):4-8.
[11]XIAO W J,WINDLEY B F,HAO J,et al.Accretion leading to collision and the Permian Solonker suture,inner Mongolia,China:termination of the Central Asian orogenic belt[J].Tectonics,2003,22(6):1069.
[12]XIAO W J,WINDLEY B F,HUANG B C,et al.End-Permian to mid-Triassic termination of the accretionary processes of the southern Altaids:implications for the geodynamic evolution,Phanerozoic continental growth,and metallogeny of Central Asia[J].International Journal of Earth Sciences,2009,98:1189-1217.
[13]XIAO W J,WINDLEY B F,SUN S,et al.A tale of amalgamation of three Permo-Triassic collage systems in Central Asia:oroclines,sutures,and terminal accretion[J].Annual Review of Earth and Planetary Sciences,2015,43:1-31.
[14]MIAO L,ZHANG F,FAN W,et al.Phanerozoic evolution of the Inner Mongolia-Daxinganling orogenic belt in North China:constraints from geochronology of ophiolites and associated formations[J].Geology Society of London Special Publication,2007,280:223-237.
[15]EIZENHOFER P R,ZHAO G C,ZHANG J,et al.Final closure of the Paleo-Asian Ocean along Solonker suture zone:constraints from geochronological and geochemical data of Permian volcanic and sedimentary rocks[J].Tectonics,2014,33:441-463.
[16]陈志勇.内蒙古固阳-满都拉地区中元古代-古生代地质构造演化[D].北京:中国地质大学(北京),2005:1
[17]NOZAKA T,LIU Y.Petrology of the Hegenshan ophiolite and its implication for the tectonic evolution of north China[J].Earth and Planetary Science Letters,2002,202:89-104.
[18]陶继雄,苏茂荣,宝音乌力吉,等.内蒙古达尔罕茂明安联合旗满都拉地区索伦山蛇绿混杂岩的特征及构造意义[J].地质通报,2004,23(12):1238-1242.
[19]LI Y L,ZHOU H W,BROUWER F M,et al.Tectonic significance of the Xilin Gol complex,Inner Mongolia,China:petrological,geochemical,and U-Pb zircon age constraints[J].Asian Earth Sciences,2011,42:1018-1029.
[20]JIAN P,KRONER A,WINDLEY B F,et al.Carboniferous and Cretaceous mafic-ultramafic massifs in Inner Mongolia(China):A SHRIMP zircon and geochemical study of the previously presumed integral“Hegenshan ophiolite”[J].Lithos,2012,142/143:48-66.
[21]徐备,赵盼,鲍庆中,等.兴蒙造山带前中生代构造单元划分初探[J].岩石学报,2014,30(7):1841-1857.
[22]ANONYMOUS.Penrose field conference on ophiolites[J].Geotimes,1972,17:24-25.
[23]MOORES E M.A personal history of the ophiolite concept[M]//DILEK Y,NEWEOMB S.Ophiolite Concept and the Evolution of Geological Thought.Boulder:Geological Society of America,2003:17-29.
[24]王国强.北山古生代蛇绿岩、火山岩研究与构造演化[D].西安:长安大学,2011:1-90.
[25]WAKABAYASHI J,DILEK Y.What constitutes“emplacement”of an ophiolite?Mechanisms and relationship to subduction initiation and formation of metamorphic soles[J].Geological Society of London Special Publications,2003,218:427-447.
[26]COLEMAN R G.Ophiolites[M].Berlin,Heidelberg,New York:Springer-Verlag,1977:147-158.
[27]马冲,赵桂萍,肖文交,等.蛇绿岩就位机制及时限[J].地质科学,2011,46(3):865-874.
[28]LAGAHRIELLE Y,GUIVEL C,MAURY R C,et al.Magmatictectonic effects of high thermal regime at the site of active ridge subduction:The Chile Triple Junction model[J].Tectonophysics,2000,326(3/4):255-268.
[29]COLEMAN R G.Plate tectonic emplacement of upper mantle peridotites along continental edges[J].Journal of Geophysical Research,1971,76(5):1212-1222.
[30]OXBURGH E R.Flake tectonics and continental collision[J].Nature,1972,239:202-204.
[31]MUELLER S,PHILLIPS R J.On the initiation of subduction[J].Journal of Geophysical Research,1991,96(B1):651-665.
[32]WINDLEY B F,ALEXEIEV D,XIAO W J,et al.Tectonic models for accretion of the central Asian orogenic belt[J].Journal of the Geological Society,2007,164(1):31-47.
[33]ZHANG J E,XIAO W J,HAN C M,et al.Kinematics and age constraints of deformation in a Late Carboniferous accretionary complex in western Junggar,NW China[J].Gondwana Research,2012,19(4):958-974.
[34]ERNST W G.Alpine and Pacific styles of Phanerozoic Mountain building:Subduction-zone petrogenesis of continental crust[J].Terra Nova,2005,17(2):165-188.
[35]BOUSQUET R,EL MAMOUN R,SADDIQI O,et al.Melanges and ophiolites during the Pan-African orogeny:The case of the Bou-Azzer ophiolite suite(Morocco)[J].Geological Society of London Special Publications,2008,297:233-247.
[36]GUILLOT S,HATTORI K,AGARD P,et al.Exhumation processes in oceanic and continental subduction contexts:A review[M]//LALLEMAND S,FUNICIELLO F.Subduction Zone Geodynamics.Berlin,Heidelberg:Springer-Verlag,2009:175-205.
[37]MOORES E M.Origin and emplacement of ophiolites[J].Reviews of Geophysics,1982,20(4):735-760.
[38]DEWEY J.Ophiolites and lost oceans:Rifts,ridges,arcs and/or scrapings?[M]//DILEK Y,NEWEOMB S.Ophiolite Concept and the Evolution of Geological Thought.Boulder:Geological Society of America,2003:153-158.
[39]SMITH A G,RASSIOS A.The evolution of ideas for the origin and emplacement of the western Hellenic ophiolites[M]//DILEK Y,NEWEOMB S.Ophiolite Concept and the Evolution of Geological Thought.Boulder:Geological Society of America,2003:337-350.
[2]DILEK Y,FURNES H.Ophiolite genesis and global tectonics:Geochemical and tectonic fingerprinting of ancient oceanic lithosphere[J].Geological Society of America Bulletin,2011,123(3/4):387-411.
[3]DILEK Y,FURNES H.Ophiolites and their origins[J].Elements,2014,10(2):93-100.
[4]HAWKINS J W.Geology of supra-subduction zone:Implications for the origin of ophiolites[M]//DILEK Y,NEWEOMB S.Ophiolite Concept and the Evolution of Geological Thought.Boulder:Geological Society of America,2003:227-268.
[5]张旗,周国庆.中国蛇绿岩[M].北京:地质出版社,2001:1-15.
[6]DILEK Y.Ophiolite pulses,mantle plumes and orogeny[M]//DILEK Y,NEWCOMB S.Ophiolites in Earth History.London:Geological Society,2003:9-19.
[7]SENGOR A M C,NATAL'IN B A,BURTMAN V S.Evolution of the Altaid tectonic collage and Paleozoic crustal growth in Eurasia[J].Nature,1993,364:299-307.
[8]SENGOR A M C,NATAL'IN B A.Paleotectonics of Asia:fragments of a synthesis[M]//YIN A,HARRISON M.The Tectonic Evolution of Asia.Cambridge:Cambridge University Press,1996:486-460.
[9]LI J Y.Permian geodynamic setting of Northeast China and adjacent regions:Closure of the Paleo-Asian Ocean and subduction of the Paleo-Pacific Plate[J].Asian Earth Science,2006:26(3/4):207-224.
[10]肖文交,舒良树,高俊,等.中亚造山带大陆动力学过程与成矿作用[J].新疆地质,2008,26(1):4-8.
[11]XIAO W J,WINDLEY B F,HAO J,et al.Accretion leading to collision and the Permian Solonker suture,inner Mongolia,China:termination of the Central Asian orogenic belt[J].Tectonics,2003,22(6):1069.
[12]XIAO W J,WINDLEY B F,HUANG B C,et al.End-Permian to mid-Triassic termination of the accretionary processes of the southern Altaids:implications for the geodynamic evolution,Phanerozoic continental growth,and metallogeny of Central Asia[J].International Journal of Earth Sciences,2009,98:1189-1217.
[13]XIAO W J,WINDLEY B F,SUN S,et al.A tale of amalgamation of three Permo-Triassic collage systems in Central Asia:oroclines,sutures,and terminal accretion[J].Annual Review of Earth and Planetary Sciences,2015,43:1-31.
[14]MIAO L,ZHANG F,FAN W,et al.Phanerozoic evolution of the Inner Mongolia-Daxinganling orogenic belt in North China:constraints from geochronology of ophiolites and associated formations[J].Geology Society of London Special Publication,2007,280:223-237.
[15]EIZENHOFER P R,ZHAO G C,ZHANG J,et al.Final closure of the Paleo-Asian Ocean along Solonker suture zone:constraints from geochronological and geochemical data of Permian volcanic and sedimentary rocks[J].Tectonics,2014,33:441-463.
[16]陈志勇.内蒙古固阳-满都拉地区中元古代-古生代地质构造演化[D].北京:中国地质大学(北京),2005:1
[17]NOZAKA T,LIU Y.Petrology of the Hegenshan ophiolite and its implication for the tectonic evolution of north China[J].Earth and Planetary Science Letters,2002,202:89-104.
[18]陶继雄,苏茂荣,宝音乌力吉,等.内蒙古达尔罕茂明安联合旗满都拉地区索伦山蛇绿混杂岩的特征及构造意义[J].地质通报,2004,23(12):1238-1242.
[19]LI Y L,ZHOU H W,BROUWER F M,et al.Tectonic significance of the Xilin Gol complex,Inner Mongolia,China:petrological,geochemical,and U-Pb zircon age constraints[J].Asian Earth Sciences,2011,42:1018-1029.
[20]JIAN P,KRONER A,WINDLEY B F,et al.Carboniferous and Cretaceous mafic-ultramafic massifs in Inner Mongolia(China):A SHRIMP zircon and geochemical study of the previously presumed integral“Hegenshan ophiolite”[J].Lithos,2012,142/143:48-66.
[21]徐备,赵盼,鲍庆中,等.兴蒙造山带前中生代构造单元划分初探[J].岩石学报,2014,30(7):1841-1857.
[22]ANONYMOUS.Penrose field conference on ophiolites[J].Geotimes,1972,17:24-25.
[23]MOORES E M.A personal history of the ophiolite concept[M]//DILEK Y,NEWEOMB S.Ophiolite Concept and the Evolution of Geological Thought.Boulder:Geological Society of America,2003:17-29.
[24]王国强.北山古生代蛇绿岩、火山岩研究与构造演化[D].西安:长安大学,2011:1-90.
[25]WAKABAYASHI J,DILEK Y.What constitutes“emplacement”of an ophiolite?Mechanisms and relationship to subduction initiation and formation of metamorphic soles[J].Geological Society of London Special Publications,2003,218:427-447.
[26]COLEMAN R G.Ophiolites[M].Berlin,Heidelberg,New York:Springer-Verlag,1977:147-158.
[27]马冲,赵桂萍,肖文交,等.蛇绿岩就位机制及时限[J].地质科学,2011,46(3):865-874.
[28]LAGAHRIELLE Y,GUIVEL C,MAURY R C,et al.Magmatictectonic effects of high thermal regime at the site of active ridge subduction:The Chile Triple Junction model[J].Tectonophysics,2000,326(3/4):255-268.
[29]COLEMAN R G.Plate tectonic emplacement of upper mantle peridotites along continental edges[J].Journal of Geophysical Research,1971,76(5):1212-1222.
[30]OXBURGH E R.Flake tectonics and continental collision[J].Nature,1972,239:202-204.
[31]MUELLER S,PHILLIPS R J.On the initiation of subduction[J].Journal of Geophysical Research,1991,96(B1):651-665.
[32]WINDLEY B F,ALEXEIEV D,XIAO W J,et al.Tectonic models for accretion of the central Asian orogenic belt[J].Journal of the Geological Society,2007,164(1):31-47.
[33]ZHANG J E,XIAO W J,HAN C M,et al.Kinematics and age constraints of deformation in a Late Carboniferous accretionary complex in western Junggar,NW China[J].Gondwana Research,2012,19(4):958-974.
[34]ERNST W G.Alpine and Pacific styles of Phanerozoic Mountain building:Subduction-zone petrogenesis of continental crust[J].Terra Nova,2005,17(2):165-188.
[35]BOUSQUET R,EL MAMOUN R,SADDIQI O,et al.Melanges and ophiolites during the Pan-African orogeny:The case of the Bou-Azzer ophiolite suite(Morocco)[J].Geological Society of London Special Publications,2008,297:233-247.
[36]GUILLOT S,HATTORI K,AGARD P,et al.Exhumation processes in oceanic and continental subduction contexts:A review[M]//LALLEMAND S,FUNICIELLO F.Subduction Zone Geodynamics.Berlin,Heidelberg:Springer-Verlag,2009:175-205.
[37]MOORES E M.Origin and emplacement of ophiolites[J].Reviews of Geophysics,1982,20(4):735-760.
[38]DEWEY J.Ophiolites and lost oceans:Rifts,ridges,arcs and/or scrapings?[M]//DILEK Y,NEWEOMB S.Ophiolite Concept and the Evolution of Geological Thought.Boulder:Geological Society of America,2003:153-158.
[39]SMITH A G,RASSIOS A.The evolution of ideas for the origin and emplacement of the western Hellenic ophiolites[M]//DILEK Y,NEWEOMB S.Ophiolite Concept and the Evolution of Geological Thought.Boulder:Geological Society of America,2003:337-350.