北祁连牛心山岩体岩石学、锆石SHRIMP定年及其成因
摘要
花岗岩作为壳幔相互作用的产物,承载着丰富的地质过程信息。然而,目前北祁连古生代花岗岩类研究程度不高,极大地影响了地学工作者对该区古生代花岗岩质岩浆作用与造山响应的认识。基于上述存在的问题,本项研究的目的是:判断研究区岩浆活动期次,判别其成因类型和构造环境,分析其造山响应。为达到上述目的,本项研究采用野外地质调查、实验室分析测试和综合分析相结合的研究方法。
通过对北祁连中段牛心山岩体的地质学、年代学、岩相学、地球化学及岩石成因学等方面的研究,取得了以下五方面的成果:
(1)研究表明,该杂岩体主要由花岗岩类和闪长岩类组成。早期的花岗岩和闪长岩几乎同时侵位;但晚期的石英闪长岩类以脉状产出于花岗岩当中,说明其侵位要晚于花岗岩。花岗岩岩体中发现大量的暗色包体,说明岩体形成过程中存在一定规模的岩浆混合作用。
(2)锆石SHRIMP U-Pb定年表明,牛心山岩体的花岗岩类年龄463±11─480.9±4Ma,闪长岩为481.8±3.2Ma,石英闪长岩为434.7±3.5Ma,由此,将牛心山地区的岩浆活动分为两期:早期为花岗岩与闪长岩的组合;晚期为石英闪长岩,这与野外观察到的现象是一致的。
(3)岩石地球化学研究表明,早期的花岗岩类为S型,闪长岩为I型,晚期的石英闪长岩为I型,并具有高Sr、低Y的特征,类似于埃达克岩,说明花岗岩的源岩来自地壳,而闪长岩和石英闪长岩的源岩来自壳幔混合。
(4)锆石温度计和金红石温度计计算结果表明,早期花岗岩的形成温度分别为779℃和879℃,早期闪长岩形成的温度分别是656℃和844℃,晚期的石英闪长岩形成的温度为708℃和883℃。结合前人的研究成果,作者认为金红石温度计得到的温度结果更加接近于岩石的真实温度,而在接近50Ma的时间间隔中,岩浆房仍然能保持较高的温度,说明岩浆房在接近50Ma的过程中都有源源不断的热源供应。
(5)在上述研究的基础上,结合区域地质特征,作者认为,早期的岩浆作用与北祁连板块向南俯冲有关。俯冲的板块在俯冲过程中发生矿物脱水形成流体,流体诱导地幔楔部分熔融形成基性岩浆,基性岩浆上升到壳幔边界形成岩浆房,岩浆房自身的热和结晶潜热引起地壳部分熔融形成花岗质岩浆,晚期的石英闪长质岩浆作用与造山后造山带伸展作用有关。
As a product of the crust-mantle interaction, Granites carry a wealth of information on geological processes. However, the studies of the North Qilian Paleozoic granitoids are not enough, which greatly affect understand of the geoscience workers in the area. Based on the above-mentioned problems, the purpose of this study is to determine stages of magmatic activity, to identify the causes of the type and structure of its environment, to analyze its response to orogeny. To achieve the above objectives, this study adopts field geological survey, laboratory analysis and testing and comprehensive analysis of combining research.
With the study of the middle of the North Qilian Mountai, we get the following five achievements:
(1) Research indicated that, this mixed rock mass is composed by the diorite class and the granite class. The early granite and the diorite nearly simultaneously invade the position; But the later period quartz-diorite class delivers by the arteries shape in the middle of the granite, explained it invades the position to have late in the granite.In the granite rock mass discovered the massive dark color inclusion, showed in the rock mass forming process has certain scale the rock magma mixer action.
(2) Zircon SHRIMP U-Pb dating indicate that, the Niuxinshan precipice body granite class age 463±11-481.8±3.2Ma, the diorite for 480.9±4Ma, the quartz-diorite for 434.7±3.5Ma, from this, divides into the Niuxinshan mountainous region area magmatic activity two issues: The early one is for the granite and the diorite combination, both nearly simultaneously invades the position; The later is the quartz-diorite, this is consistent with the field observation phenomenon.
(3) Rock geochemistry research indicated that, the early granite is S, the diorite is I, the later period quartz-diorite is I, and has high Sr, the low Y characteristic, which is similar in the Adakites, explained the granite the source rock comes from the earth's crust, but the diorite and the quartz-diorite source rock comes from mixing between crust and mantle.
(4) Both the zircon and the rutile thermometer show that, the early granites have temperature to be 779℃and 879℃, the early diorite for 656℃and 844℃, the later quartz-diorite 708℃and 883℃.
(5) In the above research foundation, unifies the regional geology characteristic, the author believed that, the early magmatism form when the northern Qilian tectonic plate dives to the south concerns.The dive tectonic plate has the mineral dehydration in the dive process to form the fluid, fluid induction mantle wedge part fusing forms the basic rock magma, the basic rock magma rises to the shell curtain boundary forms the magma chamber, magma chamber own heat and the crystallization latent heat causes the earth's crust part fusing to form the flowered hillock nature rock magma.And the later quartz magmatism is related with orogenic extension function of the mountain building.
通过对北祁连中段牛心山岩体的地质学、年代学、岩相学、地球化学及岩石成因学等方面的研究,取得了以下五方面的成果:
(1)研究表明,该杂岩体主要由花岗岩类和闪长岩类组成。早期的花岗岩和闪长岩几乎同时侵位;但晚期的石英闪长岩类以脉状产出于花岗岩当中,说明其侵位要晚于花岗岩。花岗岩岩体中发现大量的暗色包体,说明岩体形成过程中存在一定规模的岩浆混合作用。
(2)锆石SHRIMP U-Pb定年表明,牛心山岩体的花岗岩类年龄463±11─480.9±4Ma,闪长岩为481.8±3.2Ma,石英闪长岩为434.7±3.5Ma,由此,将牛心山地区的岩浆活动分为两期:早期为花岗岩与闪长岩的组合;晚期为石英闪长岩,这与野外观察到的现象是一致的。
(3)岩石地球化学研究表明,早期的花岗岩类为S型,闪长岩为I型,晚期的石英闪长岩为I型,并具有高Sr、低Y的特征,类似于埃达克岩,说明花岗岩的源岩来自地壳,而闪长岩和石英闪长岩的源岩来自壳幔混合。
(4)锆石温度计和金红石温度计计算结果表明,早期花岗岩的形成温度分别为779℃和879℃,早期闪长岩形成的温度分别是656℃和844℃,晚期的石英闪长岩形成的温度为708℃和883℃。结合前人的研究成果,作者认为金红石温度计得到的温度结果更加接近于岩石的真实温度,而在接近50Ma的时间间隔中,岩浆房仍然能保持较高的温度,说明岩浆房在接近50Ma的过程中都有源源不断的热源供应。
(5)在上述研究的基础上,结合区域地质特征,作者认为,早期的岩浆作用与北祁连板块向南俯冲有关。俯冲的板块在俯冲过程中发生矿物脱水形成流体,流体诱导地幔楔部分熔融形成基性岩浆,基性岩浆上升到壳幔边界形成岩浆房,岩浆房自身的热和结晶潜热引起地壳部分熔融形成花岗质岩浆,晚期的石英闪长质岩浆作用与造山后造山带伸展作用有关。
As a product of the crust-mantle interaction, Granites carry a wealth of information on geological processes. However, the studies of the North Qilian Paleozoic granitoids are not enough, which greatly affect understand of the geoscience workers in the area. Based on the above-mentioned problems, the purpose of this study is to determine stages of magmatic activity, to identify the causes of the type and structure of its environment, to analyze its response to orogeny. To achieve the above objectives, this study adopts field geological survey, laboratory analysis and testing and comprehensive analysis of combining research.
With the study of the middle of the North Qilian Mountai, we get the following five achievements:
(1) Research indicated that, this mixed rock mass is composed by the diorite class and the granite class. The early granite and the diorite nearly simultaneously invade the position; But the later period quartz-diorite class delivers by the arteries shape in the middle of the granite, explained it invades the position to have late in the granite.In the granite rock mass discovered the massive dark color inclusion, showed in the rock mass forming process has certain scale the rock magma mixer action.
(2) Zircon SHRIMP U-Pb dating indicate that, the Niuxinshan precipice body granite class age 463±11-481.8±3.2Ma, the diorite for 480.9±4Ma, the quartz-diorite for 434.7±3.5Ma, from this, divides into the Niuxinshan mountainous region area magmatic activity two issues: The early one is for the granite and the diorite combination, both nearly simultaneously invades the position; The later is the quartz-diorite, this is consistent with the field observation phenomenon.
(3) Rock geochemistry research indicated that, the early granite is S, the diorite is I, the later period quartz-diorite is I, and has high Sr, the low Y characteristic, which is similar in the Adakites, explained the granite the source rock comes from the earth's crust, but the diorite and the quartz-diorite source rock comes from mixing between crust and mantle.
(4) Both the zircon and the rutile thermometer show that, the early granites have temperature to be 779℃and 879℃, the early diorite for 656℃and 844℃, the later quartz-diorite 708℃and 883℃.
(5) In the above research foundation, unifies the regional geology characteristic, the author believed that, the early magmatism form when the northern Qilian tectonic plate dives to the south concerns.The dive tectonic plate has the mineral dehydration in the dive process to form the fluid, fluid induction mantle wedge part fusing forms the basic rock magma, the basic rock magma rises to the shell curtain boundary forms the magma chamber, magma chamber own heat and the crystallization latent heat causes the earth's crust part fusing to form the flowered hillock nature rock magma.And the later quartz magmatism is related with orogenic extension function of the mountain building.
引文
Anderson J L.1997. Status of thermoparametry in granitic batholiths . Trans . Roy. Soc. Edinb. Earth Sci., 87:125-138
Barbarin B. 1999. A review of the relationship between granitoid types, their origrins and their geodynamic environment. Lithos, 46: 605-626
Chappell B W.,Bryant C J.,Wyborn D.et al. 1998.High- and low-temperature granites. Resource Geo.,48:225-236
Chappell B. W White A. J. R. 1974. Two contrasting granite types[J], Pacific Geology, ,8:74-173
Collins W. J. 1998. Evaluation of petrogenetic models for Lachlan Fold Belt granites: implications for crustal architecture and tectonic models[J]. Australian jour of Sci., 45:483-500.
Eby, G N. 1990. The A-type granitoids: a review of their occurrence and chemical characteristics and speculations on their petrogenesis[J]. Lithos, 26, 115-134.
Harrison T M and Watson E B.1984. The behavior of apatite during crustal anatexis :Equilibrium and kinetic considerations. Geochim. Cosmochim. Acta,48:1467-1477.
Hayden L. A., Watson E. B.. 2007. Rutile saturation in hydrous siliceous melts and its bearing on Ti-thermometry of quartz and zircon[J]. Earth and Planetary Science Letters.
Loiselle M. C. and Wones D S. 1979. Characteristic and origin of anorogenic granites[J]. Geological Society of America,11:468.
Pearce. J. A., 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks, Jour petrol., 25: 956-983.
Phinney R. A., etal. (eds).1989.A National Program for research in continental dynamics, the IRIS Consortium, Arlington, USA.
Pitcher W S. 1983.The nature and origin of granite. London: Chapman and HallPitcher W S. Granite type and tectonic environment. Mountain Building Processes. London: Academic Press. 19- 40
Rittmann A. 1962.Volcanoes and their activity.
Rogers J J W, Greenberg J K. 1990. Late-orogenic, post-orogenic andanorogenic granites:distinction by major-element and trace-element chemistry and possible origins. Journal of Geology, 98(3): 291-309
Shand S J.1927. Eruptive rocks. The Woodbridge Press.
Watson E B and Harrison T M. 1983. Zircon saturations revisited : Temprature and compositioneffects in a variety of crustal magma types. Earth Planet. Sci. Lett., 64:295-304
Watson E B, Harrison T M, 2005. Zircon thermometer reveal minimum melting conditions on earliest Earth. Science,308:841-844
Wilde S A, Valley J W, Peck W H et al, 2001, Evidence from detrail zircons for the existence of continental crust and oceans on the earth 4.4 Gyr , ago. Nature, 409:175-178
董申保,田伟. 2003.花岗岩拓扑学的反思.地学前缘, 10(3): 1-13.
洪大卫, 1994。花岗岩研究的最新进展以及发展趋势.地学前缘(1)
李昌年. 1992.火成岩微量元素岩石学.中国地质大学出版社.
林广春,马昌前. 2003.过铝花岗岩的成因类型与构造环境研究综述.华南地质与矿产, 1: 65-70.
路风香,桑隆康.岩石学.北京:地质出版社.
刘传周,肖文交,袁朝,等.2005.祁连山扎麻什基性杂岩体岩石地球化学特征及其大地构造意义[J].岩石学报,21(1):57-64.
毛景文,简平. 2000.北祁连西段花岗质岩体的锆石U—Pb年龄报道[J].地质论评.
王德滋、周金城,1999,我国花岗岩研究的回顾和展望,岩石学报,15(2):61-69
王涛.2000.花岗岩混合成因研究及大陆动力学意义[J].岩石学报,16(2):161-168
吴才来,杨经绥,李海兵等. 2001.柴达木盆地北缘西端冷湖花岗岩[J],中国区域地质, 20(1):73-81
吴才来,姚尚志,杨经绥等,2006.北祁连洋早古生代双向俯冲的花岗岩证据.中国地质,33(6): 1197-1208.
吴才来. 1994.长江中下游铜陵地区中生代中酸性侵入岩岩石学及岩浆动力学研究.
吴福元,李献华,杨进辉等. 2007.花岗岩成因研究的若干问题[J].岩石学报,23(6):1217-1238
吴锁平,王梅英,戚开静. 2007. A型花岗岩研究现状及其述评[J],岩石矿物学杂志, 26(1): 57~66.
吴汉泉,杨宏仪. 2002.北祁连新元古代俯冲事件及早古生代消减方向的转换[J].第三届海峡两岸祁连山及邻区地学研讨会——中央造山带的演化论文集.
夏林圻,夏祖春,徐学义.1998.北祁连洋壳一洋脊和弧后盆地火山作用[J].地质学报,72(4):301~312.
肖庆辉,邓晋福,马大栓等,2003.花岗岩研究思维与方法[M].北京:地质出版社:102-112
肖序常,李廷栋,李光岑,等. 1988.喜马拉雅岩石圈构造演化总论[M].北京:地质出版社.
徐克勤,孙鼐,王德滋,等. 1982.华南两类不同成因花岗岩岩石学特征.江苏地质学会年会, 1(2):1-13.
许志琴,徐惠芬,张建新,等.1994.北祁连走廊南山加里东俯冲杂岩增生地体及其动力学[J].地质学报,68(1):1~15.
许文良,王冬艳,高山等. 2003,鲁西中生代金岭闪长岩中纯橄岩和辉石岩包体的发现及其意义.科学通报, 48(8): 863-868.
袁洪林,吴福元,高山等,2003,东北地区新生代侵入岩的激光锆石探针U-Pb年龄测定与稀土元素成分析[J],科学通报,48(4):511-520
杨怀仁,杨宏仪,刘敦一,等. 2007.北祁连东草河蛇绿岩:一个早古生代的洋壳残片[J].科学通报,52(7):825-835.
张建新,许志琴,陈文等.1997.北祁连中段俯冲一增生杂岩/火山弧的时代探讨.岩石矿物杂志, 16:112~119.
张德全,孙桂英. 1995.祁连山金佛寺岩体的岩石学和同位素年代学研究.地球学报:中国地质科学院院报.
张德全,孙桂英. 1988.中国东部花岗岩.地质出版社.
左国朝,刘寄陈.1987.北祁连早古生代大地构造演化[J].地质科学,(1):14~24.
左国朝,吴汉泉.1997.北祁连山中段早古生代双向俯冲一碰撞造山模式剖析.地球科学进展, 12(4):315-323.
Barbarin B. 1999. A review of the relationship between granitoid types, their origrins and their geodynamic environment. Lithos, 46: 605-626
Chappell B W.,Bryant C J.,Wyborn D.et al. 1998.High- and low-temperature granites. Resource Geo.,48:225-236
Chappell B. W White A. J. R. 1974. Two contrasting granite types[J], Pacific Geology, ,8:74-173
Collins W. J. 1998. Evaluation of petrogenetic models for Lachlan Fold Belt granites: implications for crustal architecture and tectonic models[J]. Australian jour of Sci., 45:483-500.
Eby, G N. 1990. The A-type granitoids: a review of their occurrence and chemical characteristics and speculations on their petrogenesis[J]. Lithos, 26, 115-134.
Harrison T M and Watson E B.1984. The behavior of apatite during crustal anatexis :Equilibrium and kinetic considerations. Geochim. Cosmochim. Acta,48:1467-1477.
Hayden L. A., Watson E. B.. 2007. Rutile saturation in hydrous siliceous melts and its bearing on Ti-thermometry of quartz and zircon[J]. Earth and Planetary Science Letters.
Loiselle M. C. and Wones D S. 1979. Characteristic and origin of anorogenic granites[J]. Geological Society of America,11:468.
Pearce. J. A., 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks, Jour petrol., 25: 956-983.
Phinney R. A., etal. (eds).1989.A National Program for research in continental dynamics, the IRIS Consortium, Arlington, USA.
Pitcher W S. 1983.The nature and origin of granite. London: Chapman and HallPitcher W S. Granite type and tectonic environment. Mountain Building Processes. London: Academic Press. 19- 40
Rittmann A. 1962.Volcanoes and their activity.
Rogers J J W, Greenberg J K. 1990. Late-orogenic, post-orogenic andanorogenic granites:distinction by major-element and trace-element chemistry and possible origins. Journal of Geology, 98(3): 291-309
Shand S J.1927. Eruptive rocks. The Woodbridge Press.
Watson E B and Harrison T M. 1983. Zircon saturations revisited : Temprature and compositioneffects in a variety of crustal magma types. Earth Planet. Sci. Lett., 64:295-304
Watson E B, Harrison T M, 2005. Zircon thermometer reveal minimum melting conditions on earliest Earth. Science,308:841-844
Wilde S A, Valley J W, Peck W H et al, 2001, Evidence from detrail zircons for the existence of continental crust and oceans on the earth 4.4 Gyr , ago. Nature, 409:175-178
董申保,田伟. 2003.花岗岩拓扑学的反思.地学前缘, 10(3): 1-13.
洪大卫, 1994。花岗岩研究的最新进展以及发展趋势.地学前缘(1)
李昌年. 1992.火成岩微量元素岩石学.中国地质大学出版社.
林广春,马昌前. 2003.过铝花岗岩的成因类型与构造环境研究综述.华南地质与矿产, 1: 65-70.
路风香,桑隆康.岩石学.北京:地质出版社.
刘传周,肖文交,袁朝,等.2005.祁连山扎麻什基性杂岩体岩石地球化学特征及其大地构造意义[J].岩石学报,21(1):57-64.
毛景文,简平. 2000.北祁连西段花岗质岩体的锆石U—Pb年龄报道[J].地质论评.
王德滋、周金城,1999,我国花岗岩研究的回顾和展望,岩石学报,15(2):61-69
王涛.2000.花岗岩混合成因研究及大陆动力学意义[J].岩石学报,16(2):161-168
吴才来,杨经绥,李海兵等. 2001.柴达木盆地北缘西端冷湖花岗岩[J],中国区域地质, 20(1):73-81
吴才来,姚尚志,杨经绥等,2006.北祁连洋早古生代双向俯冲的花岗岩证据.中国地质,33(6): 1197-1208.
吴才来. 1994.长江中下游铜陵地区中生代中酸性侵入岩岩石学及岩浆动力学研究.
吴福元,李献华,杨进辉等. 2007.花岗岩成因研究的若干问题[J].岩石学报,23(6):1217-1238
吴锁平,王梅英,戚开静. 2007. A型花岗岩研究现状及其述评[J],岩石矿物学杂志, 26(1): 57~66.
吴汉泉,杨宏仪. 2002.北祁连新元古代俯冲事件及早古生代消减方向的转换[J].第三届海峡两岸祁连山及邻区地学研讨会——中央造山带的演化论文集.
夏林圻,夏祖春,徐学义.1998.北祁连洋壳一洋脊和弧后盆地火山作用[J].地质学报,72(4):301~312.
肖庆辉,邓晋福,马大栓等,2003.花岗岩研究思维与方法[M].北京:地质出版社:102-112
肖序常,李廷栋,李光岑,等. 1988.喜马拉雅岩石圈构造演化总论[M].北京:地质出版社.
徐克勤,孙鼐,王德滋,等. 1982.华南两类不同成因花岗岩岩石学特征.江苏地质学会年会, 1(2):1-13.
许志琴,徐惠芬,张建新,等.1994.北祁连走廊南山加里东俯冲杂岩增生地体及其动力学[J].地质学报,68(1):1~15.
许文良,王冬艳,高山等. 2003,鲁西中生代金岭闪长岩中纯橄岩和辉石岩包体的发现及其意义.科学通报, 48(8): 863-868.
袁洪林,吴福元,高山等,2003,东北地区新生代侵入岩的激光锆石探针U-Pb年龄测定与稀土元素成分析[J],科学通报,48(4):511-520
杨怀仁,杨宏仪,刘敦一,等. 2007.北祁连东草河蛇绿岩:一个早古生代的洋壳残片[J].科学通报,52(7):825-835.
张建新,许志琴,陈文等.1997.北祁连中段俯冲一增生杂岩/火山弧的时代探讨.岩石矿物杂志, 16:112~119.
张德全,孙桂英. 1995.祁连山金佛寺岩体的岩石学和同位素年代学研究.地球学报:中国地质科学院院报.
张德全,孙桂英. 1988.中国东部花岗岩.地质出版社.
左国朝,刘寄陈.1987.北祁连早古生代大地构造演化[J].地质科学,(1):14~24.
左国朝,吴汉泉.1997.北祁连山中段早古生代双向俯冲一碰撞造山模式剖析.地球科学进展, 12(4):315-323.
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