大别造山带岩石圈结构与超高压变质岩折返的另类模型
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摘要
氦同位素研究确定,大别山榴辉岩等超高压岩石矿物并非来自地幔,而是生成于岩石圈地幔顶部。结合深部地球物理,提出一个岩石圈地幔顶部形成超高压矿物的模型。即表壳岩石俯冲到岩石圈地幔顶部,形成超高压变质岩,然后由于地壳隆升、剥蚀,出露到地表。冲入大别山地区岩石圈地幔顶部的表壳岩石之所以会形成超高压变质岩是因为它同时受到板块会聚的强大压力和蘑菇云地幔产生的高温。沿六安—黄石综合地球物理、地球化学剖面实测的热流剖面显示,南大别构造带的莫霍面温度达到1307℃,超高压变质作用所需要的高温条件至今依然存在。已有文献表明黏塑性的大陆板块在碰撞俯冲时,岩石圈地幔的变形远比通常认定的那种刚性板块俯冲要复杂。俯冲呈对冲形式,方向大都向下,在岩石圈地幔中,俯冲板块和制动板块像麻花一样相互楔入,在深部甚至改变俯冲方向,制动板块反而向俯冲板块俯冲。当岩石圈地幔顶部局部熔融时,无疑俯冲物质将向局部熔融层扩散,在高温高压下发生超高压变质作用。大别山变形晚期,在核部形成"背形穹隆"。将形成于岩石圈地幔顶部的超高压变质岩带到地表,接受剥蚀而出露地表。已有资料表明,全球主要超高压变质岩的分布带与古特提斯洋分布有关,古特提斯洋碰撞带是全球最长的一条陆内碰撞俯冲带。它们是否均为黏塑性板块之间的软碰撞、在邻近碰撞带的岩石圈地幔顶部是否都有高温的区域则尚待验证。
Study of helium isotrope of UHP rocks in the Dabie area shows that minerals of UHP rocks such as eclogite in the Dabie area were not derived from the mantle but formed at top of the lithospheric mantle (LID). According to the deep geophysical data, the authors propose a new model for the formation of UHP minerals at the lithospheric mantle lid, i.e. when supracrustal rocks were subducted to the LID, UHP metamorphic rocks were formed at strong pressures caused by convergence of plates and high temperatures produced by the mushroom cloud mantle, and then were exposed at the surface due to doming and erosion of the crust. The available literature indicates that when visco-plastic continental plates collided and were subducted the deformation of the LID was much more complex than the deformation due to subduction of a rigid plate. The direction of subduction was mostly vertically downward, and the subducted plate and retro-side wedged each other like fried dough twist and the subducting direction might change at depth. When the LID partially melted, subducted materials would spread in the locally molten layer and formed UHP metamorphic rocks at high pressures and temperatures. The global distribution of main UHP metamorphic rocks is associated with the distribution of the Paleo-Tethys Ocean. However, it is not certain whether both of them were soft collision between visco-plastic continental plates and whether there were high-temperature regions at the LID near the collision zone.
Study of helium isotrope of UHP rocks in the Dabie area shows that minerals of UHP rocks such as eclogite in the Dabie area were not derived from the mantle but formed at top of the lithospheric mantle (LID). According to the deep geophysical data, the authors propose a new model for the formation of UHP minerals at the lithospheric mantle lid, i.e. when supracrustal rocks were subducted to the LID, UHP metamorphic rocks were formed at strong pressures caused by convergence of plates and high temperatures produced by the mushroom cloud mantle, and then were exposed at the surface due to doming and erosion of the crust. The available literature indicates that when visco-plastic continental plates collided and were subducted the deformation of the LID was much more complex than the deformation due to subduction of a rigid plate. The direction of subduction was mostly vertically downward, and the subducted plate and retro-side wedged each other like fried dough twist and the subducting direction might change at depth. When the LID partially melted, subducted materials would spread in the locally molten layer and formed UHP metamorphic rocks at high pressures and temperatures. The global distribution of main UHP metamorphic rocks is associated with the distribution of the Paleo-Tethys Ocean. However, it is not certain whether both of them were soft collision between visco-plastic continental plates and whether there were high-temperature regions at the LID near the collision zone.
引文
[1]许志琴.扬子板块北缘的大型深层滑脱构造及动力学分析[J],中国区域地质,1987,6(4):289-300.Xu Zhiqin.Large deep-level décollement structure on the northern margin of the Yangtze Plate and its dynamic analysis[J].Regional Geology of China,1987,6(4):289-300(in Chinese with English abstruct).
[2]Wang Xiaomin,Liou J G,Mao H K.Coesite-bearing eclogite from Dabie Mountain in central China,Geology,1989,17:1085-1088.
[3]Xu S,Okay A I,Ji S Y,et al.Diamond from the Dabie Shan metamorphic rocks and its implication for tectonic setting[J].Science,1992,256:80-82.
[4]Yuan Xuecheng,Simon L,K,Teng Wenbang,et al.Crustal structure and exhumation of the Dabie Shan ultrahigh-pressure orogen,eastern China,from seismic reflection profiling[J],Geology,2003,May,31(5):435-438.
[5]《超高压变质作用与碰撞造山动力学》编写组.超高压变质作用与碰撞造山动力学.2000.Compliation Team of%Ultrahigh-Pressure Metamorphism and Collisional Orogeny Dynamics.Ultrahigh-Pressure Metamorphism and Collisional Orogeny Dynamics.2000(in Chinese).
[6]Anderson D L,Foulger G R,Meibom A.Helium:Fundamental models[J].www.MantlePlumes.org,2006.
[7]李善芳,李延河,丁悌平,等.大别山超高压变质榴辉岩的氦同位素组成及对其形成环境的制约[J].地质论评,2005,51(3):243-249.Li Shanfang,Li Yanhe,Ding Tiping,et al.Helium isotope compositions and forming conditions of UHP metamorphc eclogites from the Dabie Mts.Terrane in East China[J].Geological Review,2005,51(3):243-249(in Chinese with English abstruct).
[8]Cloos M,Shreve R L.Subduction-channel model of prism accretion,mélange formation,sediment subduction,and subduction erosion at convevgent plate margins:1.Background and description[J].Pure and Applied Geophysics,1988,128(3/4):457-500.
[9]Maruyama M,Liou J G,Zhang R.Tectonic evolution of the ultrahigh-pressure and high-pressure metamorphic belts from central China[J]:The Island Arc,Jour.Mineral.,1994,3:112-121.
[10]Ernst W G,Liou J G.Ultra-high pressure metamorphism and geodynamics in collision-type orogenic belts[C]//Final report of the Task GroupⅢ-6of the International Lithospherre Project,International Book Series,Volume4,Bellwether Publishing,Ltd for the GSA2000,293.
[11]Chopin C.Very-high-pressure metamorphism in the western Alps:implications for subduction of continental crust[J],Phil.Trans.R.Soc.Land.1987,A321:183-197.
[12]Platt J P.Dynamics of orogenic wedges and the uplift of high-presuure metamorphic rocks[J].Geological Society of America Bulletin,1986,97:037-1053.
[13]Coney P J.The regional tectonic setting and possible causes of Cenozoic extension in the North American Cordillera[C]//in Coward M P,et al(eds.).Continental Extensional Tectonics,1987:177-186.
[14]Butler R W H.,Thrust-tectonics,deep structure and crust subduction in Alps and Himalayas[J].J.Geol.Soc.London,1986,143:857-873.
[15]金振民,金淑燕,高山,等.大别山超高压岩石形成深度局限于100-150km吗-[J].科学通报,1998,43(7):767-770.Jin Zhenmin,Jin Shuyan,Gao Shan,et al.Is the formation depth of the Dabie UHP rocks restricted to100-150km-[J].Chinese Science Bullrtin,1998,43(7),767-770(in Chinese).
[16]汤加富,周存亭,侯明金,等.大别山及邻区地质构造特征与形成演化[M].北京:地质出版社,2003:264.Tang Jiafu,Zhou Cunting,Hou Mingjin,et al.The Geological Characteristics,Formation and Evolution of Dabie Mountains and Its Adjacent Regions[M].Beijing:Giological Publishing House,2003.264(in Chinese).
[17]马昌前,杨坤光,许长海,等.大别山中生代钾质岩浆作用与超高压变质地体的剥露机理[J].岩石学报,1999,15(3)379-393.Ma Changqian,Yang Kunguang,Xu Changhai,et al.Mesozoic potassic magmatism in the Dabie Mountains:Implicaton for exhumation mechanism of ultrahigh-pressure metamorphic terranes[J].Acta Petrologica Sinica,1999,15(3):379-393(in Chinese with English abstruct).
[18]吕古贤,陈晶,李晓波,等.构造附加静水压力与含柯石英榴辉岩成岩深度测算[J].科学通报,1998,43(24):2590-2602.LüGuxian,Chen Jing,Li Xiaobo,et al.Measurements of additional structural hydrostatic pressures and depths of formation of coesite-bearing eclogite[J].Chinese Science Bulletin,1998,43(24):2590-2602(in Chinese).
[19]王方正.高压、超高压变质岩形成深度讨论[J].地球科学-中国地质大学学报,1996,21(1):41-44.Wang Fangzheng.Depth of high-pressure and ultra-high-pressure metamorphism[J].Earth Science-Journal of China University of Geosciences,1996,21(1):41-44(in Chinese with English abstruct).
[20]袁学诚.秦岭岩石圈速度结构与蘑菇云构造模型[J].中国科学,(D辑),1996,26(3):209-215.Yuan Xuecheng.Velocity structure of the Qinling lithosphere and mushroom cloud model[J].Science in China(SeriesD),1996,36(3):235-244.
[21]袁学诚,再论岩石圈地幔蘑菇云构造及其深部成因[J].中国地质,2007,34(5):737-758.Yuan Xuecheng.Mushroom structure of the lithospheric mantle and its genesis at depth:[J].Geology in China,2007,34(5):737-758(in Chinese with English abstruct).
[22]路凤香,郑建平,李伍平,等,中国东部显生宙地幔演化的主要样式:“蘑菇云”模型[J].地学前缘,2000,7(1):97-106.Lu Fengxiang,Zheng Jianping,Li Wuping,et al.The main evolution pattern of Phanerozoic mantle in the eastern China:the“mushroom cloud”model[J].Earth Science Frontiers,2000,7(1):97-106(in Chin ese with English abstruct).
[23]金昕,任光辉,曾建华,等.东秦岭造山带岩石圈热结构及断面模型[J].中国科学,1996,26(增刊):13-22.Jin Xin,Ren Guanghui,Zeng Jianhua,et al.Lithospheric thermal structure and section model in the East Qinling orogenic belt[J].Science in China(Supp.),1996,26,13-22(in Chinese).
[24]王清晨,从柏林.大别山超高压变质带的大地构造框架[J].岩石学报[J].1998,14:481-492.Wang Qingchen,Cong Bolin.Tectonic Framework of the Ultrahigh-Pressure metamorphic zone from the Dabie Mountains[J].Acta Petrologa Sinca,1998,14(3)481-492(in Chinese with English abstruct).
[25]Wang Q,Cong B.Exhumation of UHP Terranes:A case study from the Dabie Mountains,Eastern China[C]//Ernst WG and Liou JG(ed.).Ultra-high Pressure Metamorphism and Geodynamics in collision-type orogenic belts,2000,GSA,293.
[26]Pysklywec R N.Beaumont C,Fullsack P.Modeling the behavior of the continental mantle lithosphere during plate convergence[J].Geology,2000,28:655-658.
[27]Pysklywec R N.Evolution of subducting mantle lithosphere at a continental plate boundary[J].Geophysical Research Letters,200128(23):4399-4402.
[28]汤加富,钱存照,高天山.大别山榴辉岩浅变质火山-碎屑岩层组合的发现及其地质意义[J].安徽地质,1995,5(2):29-36.Tang Jiafu,Qian Cunzhao,Gao Tianshan.The discovery of meso-and epi-metamorphic volcanic clastic rock bed association in the eclogite belt and its geologic implications,the Dabie Mt,Area[J].Geology of Anhui,1995,5(2):29-36(in Chinese with English abstruct).
[29]杨经绥,许志琴,裴先治,等.秦岭发现金刚石:横贯中国中部巨型超高压变质带新证据及古生代和中生代两期深俯冲作用的识别[J].地质学报,2002,76(4):484-495.Yang Jingsui,Xu Zhiqin,Pei Xianzhi,et al,Discovery of diamond in North Qinling:Evidence for a giant UHPM belt acrosscentral China and recognition of Paleozoic and Mesozoic Dual deep subduction between North China and Yangtze Plates[J].Acta Geologica Sinica,2002,76(4):484-495(in Chinese with English abstruct).
[2]Wang Xiaomin,Liou J G,Mao H K.Coesite-bearing eclogite from Dabie Mountain in central China,Geology,1989,17:1085-1088.
[3]Xu S,Okay A I,Ji S Y,et al.Diamond from the Dabie Shan metamorphic rocks and its implication for tectonic setting[J].Science,1992,256:80-82.
[4]Yuan Xuecheng,Simon L,K,Teng Wenbang,et al.Crustal structure and exhumation of the Dabie Shan ultrahigh-pressure orogen,eastern China,from seismic reflection profiling[J],Geology,2003,May,31(5):435-438.
[5]《超高压变质作用与碰撞造山动力学》编写组.超高压变质作用与碰撞造山动力学.2000.Compliation Team of%Ultrahigh-Pressure Metamorphism and Collisional Orogeny Dynamics.Ultrahigh-Pressure Metamorphism and Collisional Orogeny Dynamics.2000(in Chinese).
[6]Anderson D L,Foulger G R,Meibom A.Helium:Fundamental models[J].www.MantlePlumes.org,2006.
[7]李善芳,李延河,丁悌平,等.大别山超高压变质榴辉岩的氦同位素组成及对其形成环境的制约[J].地质论评,2005,51(3):243-249.Li Shanfang,Li Yanhe,Ding Tiping,et al.Helium isotope compositions and forming conditions of UHP metamorphc eclogites from the Dabie Mts.Terrane in East China[J].Geological Review,2005,51(3):243-249(in Chinese with English abstruct).
[8]Cloos M,Shreve R L.Subduction-channel model of prism accretion,mélange formation,sediment subduction,and subduction erosion at convevgent plate margins:1.Background and description[J].Pure and Applied Geophysics,1988,128(3/4):457-500.
[9]Maruyama M,Liou J G,Zhang R.Tectonic evolution of the ultrahigh-pressure and high-pressure metamorphic belts from central China[J]:The Island Arc,Jour.Mineral.,1994,3:112-121.
[10]Ernst W G,Liou J G.Ultra-high pressure metamorphism and geodynamics in collision-type orogenic belts[C]//Final report of the Task GroupⅢ-6of the International Lithospherre Project,International Book Series,Volume4,Bellwether Publishing,Ltd for the GSA2000,293.
[11]Chopin C.Very-high-pressure metamorphism in the western Alps:implications for subduction of continental crust[J],Phil.Trans.R.Soc.Land.1987,A321:183-197.
[12]Platt J P.Dynamics of orogenic wedges and the uplift of high-presuure metamorphic rocks[J].Geological Society of America Bulletin,1986,97:037-1053.
[13]Coney P J.The regional tectonic setting and possible causes of Cenozoic extension in the North American Cordillera[C]//in Coward M P,et al(eds.).Continental Extensional Tectonics,1987:177-186.
[14]Butler R W H.,Thrust-tectonics,deep structure and crust subduction in Alps and Himalayas[J].J.Geol.Soc.London,1986,143:857-873.
[15]金振民,金淑燕,高山,等.大别山超高压岩石形成深度局限于100-150km吗-[J].科学通报,1998,43(7):767-770.Jin Zhenmin,Jin Shuyan,Gao Shan,et al.Is the formation depth of the Dabie UHP rocks restricted to100-150km-[J].Chinese Science Bullrtin,1998,43(7),767-770(in Chinese).
[16]汤加富,周存亭,侯明金,等.大别山及邻区地质构造特征与形成演化[M].北京:地质出版社,2003:264.Tang Jiafu,Zhou Cunting,Hou Mingjin,et al.The Geological Characteristics,Formation and Evolution of Dabie Mountains and Its Adjacent Regions[M].Beijing:Giological Publishing House,2003.264(in Chinese).
[17]马昌前,杨坤光,许长海,等.大别山中生代钾质岩浆作用与超高压变质地体的剥露机理[J].岩石学报,1999,15(3)379-393.Ma Changqian,Yang Kunguang,Xu Changhai,et al.Mesozoic potassic magmatism in the Dabie Mountains:Implicaton for exhumation mechanism of ultrahigh-pressure metamorphic terranes[J].Acta Petrologica Sinica,1999,15(3):379-393(in Chinese with English abstruct).
[18]吕古贤,陈晶,李晓波,等.构造附加静水压力与含柯石英榴辉岩成岩深度测算[J].科学通报,1998,43(24):2590-2602.LüGuxian,Chen Jing,Li Xiaobo,et al.Measurements of additional structural hydrostatic pressures and depths of formation of coesite-bearing eclogite[J].Chinese Science Bulletin,1998,43(24):2590-2602(in Chinese).
[19]王方正.高压、超高压变质岩形成深度讨论[J].地球科学-中国地质大学学报,1996,21(1):41-44.Wang Fangzheng.Depth of high-pressure and ultra-high-pressure metamorphism[J].Earth Science-Journal of China University of Geosciences,1996,21(1):41-44(in Chinese with English abstruct).
[20]袁学诚.秦岭岩石圈速度结构与蘑菇云构造模型[J].中国科学,(D辑),1996,26(3):209-215.Yuan Xuecheng.Velocity structure of the Qinling lithosphere and mushroom cloud model[J].Science in China(SeriesD),1996,36(3):235-244.
[21]袁学诚,再论岩石圈地幔蘑菇云构造及其深部成因[J].中国地质,2007,34(5):737-758.Yuan Xuecheng.Mushroom structure of the lithospheric mantle and its genesis at depth:[J].Geology in China,2007,34(5):737-758(in Chinese with English abstruct).
[22]路凤香,郑建平,李伍平,等,中国东部显生宙地幔演化的主要样式:“蘑菇云”模型[J].地学前缘,2000,7(1):97-106.Lu Fengxiang,Zheng Jianping,Li Wuping,et al.The main evolution pattern of Phanerozoic mantle in the eastern China:the“mushroom cloud”model[J].Earth Science Frontiers,2000,7(1):97-106(in Chin ese with English abstruct).
[23]金昕,任光辉,曾建华,等.东秦岭造山带岩石圈热结构及断面模型[J].中国科学,1996,26(增刊):13-22.Jin Xin,Ren Guanghui,Zeng Jianhua,et al.Lithospheric thermal structure and section model in the East Qinling orogenic belt[J].Science in China(Supp.),1996,26,13-22(in Chinese).
[24]王清晨,从柏林.大别山超高压变质带的大地构造框架[J].岩石学报[J].1998,14:481-492.Wang Qingchen,Cong Bolin.Tectonic Framework of the Ultrahigh-Pressure metamorphic zone from the Dabie Mountains[J].Acta Petrologa Sinca,1998,14(3)481-492(in Chinese with English abstruct).
[25]Wang Q,Cong B.Exhumation of UHP Terranes:A case study from the Dabie Mountains,Eastern China[C]//Ernst WG and Liou JG(ed.).Ultra-high Pressure Metamorphism and Geodynamics in collision-type orogenic belts,2000,GSA,293.
[26]Pysklywec R N.Beaumont C,Fullsack P.Modeling the behavior of the continental mantle lithosphere during plate convergence[J].Geology,2000,28:655-658.
[27]Pysklywec R N.Evolution of subducting mantle lithosphere at a continental plate boundary[J].Geophysical Research Letters,200128(23):4399-4402.
[28]汤加富,钱存照,高天山.大别山榴辉岩浅变质火山-碎屑岩层组合的发现及其地质意义[J].安徽地质,1995,5(2):29-36.Tang Jiafu,Qian Cunzhao,Gao Tianshan.The discovery of meso-and epi-metamorphic volcanic clastic rock bed association in the eclogite belt and its geologic implications,the Dabie Mt,Area[J].Geology of Anhui,1995,5(2):29-36(in Chinese with English abstruct).
[29]杨经绥,许志琴,裴先治,等.秦岭发现金刚石:横贯中国中部巨型超高压变质带新证据及古生代和中生代两期深俯冲作用的识别[J].地质学报,2002,76(4):484-495.Yang Jingsui,Xu Zhiqin,Pei Xianzhi,et al,Discovery of diamond in North Qinling:Evidence for a giant UHPM belt acrosscentral China and recognition of Paleozoic and Mesozoic Dual deep subduction between North China and Yangtze Plates[J].Acta Geologica Sinica,2002,76(4):484-495(in Chinese with English abstruct).
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