辉绿岩裂缝对其磁组构的影响
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摘要
磁组构是由岩石中磁性矿物定向分布而产生的组构特征,因此磁组构分析是研究岩石组构常用的技术手段,它具有见效快、灵敏度高、无损样品等特点,近年来得到广泛应用。然而在磁组构研究工作中钻取定向样品或定向手标本时,常常会遇到天然样品含有裂缝且裂缝中充填大量近地表沉积物和自生矿物。本文针对辉绿岩裂缝充填物对其磁组构结果的影响程度做了详细研究,选用160个含裂缝的辉绿岩岩芯定向样品,通过对比去除裂缝充填物前后的磁组构变化,发现实验前后所有样品磁化率大小变化率平均值<1%,磁组构方向变化平均值<1°,因此认为辉绿岩裂缝物质对其磁组构影响甚微。矿物学和岩石磁学分析表明裂隙充填物主要为石英、长石,以及少量赤铁矿、黄铁矿和绿泥石等表生矿物。而辉绿岩的携磁矿物主要是亚铁磁性的磁铁矿,其磁化率强度约为同等质量裂缝填充物的30倍,致使辉绿岩中的裂隙充填物对磁组构的影响很小。
As a rapid and sensitive petrofabric tool, the anisotropy of magnetic susceptibility(AMS) has been extensively used instudying rock fabrics. Sometimes it is difficult to drill an intact oriented core sample without any crevice, in which various fillingminerals can be found. To analyze the crevices' effect on diabase magnetic fabrics, 160 diabase samples with crevices are selected tostudy the AMS data then remove the filling minerals in the crevices in order to compare magnetic fabric characteristics of the diabasebefore and after the treatment. The data analysis shows that the average difference in the AMS intensity of all the specimens is less than1% and the difference in the average direction also falls in <1°. From the results, we conclude that crevices of diabase dykes hardlyhave much influence on the AMS features. Mineralogy and rock magnetic studies indicate that the main mineral constituents in thediabase crevices are quartz, feldspar, hematite, pyrite, and chlorite. The AMS intensity of these filling minerals is about one thirtieth ofdiabase that is dominanted by ferromagnetic mineral of magnetite, which makes crevices to have no much effect on the AMS results.
As a rapid and sensitive petrofabric tool, the anisotropy of magnetic susceptibility(AMS) has been extensively used instudying rock fabrics. Sometimes it is difficult to drill an intact oriented core sample without any crevice, in which various fillingminerals can be found. To analyze the crevices' effect on diabase magnetic fabrics, 160 diabase samples with crevices are selected tostudy the AMS data then remove the filling minerals in the crevices in order to compare magnetic fabric characteristics of the diabasebefore and after the treatment. The data analysis shows that the average difference in the AMS intensity of all the specimens is less than1% and the difference in the average direction also falls in <1°. From the results, we conclude that crevices of diabase dykes hardlyhave much influence on the AMS features. Mineralogy and rock magnetic studies indicate that the main mineral constituents in thediabase crevices are quartz, feldspar, hematite, pyrite, and chlorite. The AMS intensity of these filling minerals is about one thirtieth ofdiabase that is dominanted by ferromagnetic mineral of magnetite, which makes crevices to have no much effect on the AMS results.
引文
敖红,邓成龙.2007.磁性矿物的磁学鉴别方法回顾[J].地球物理学进展,22(2):432-442.
段宗奇,高星,刘青松.2012.非磁滞剩磁(ARM)及其在地学中的应用[J].地球物理学进展,27(5):1929-1938.
黄菲,寇大明,姚玉增,等.2009.拉曼光谱研究天然Fe S2晶须结构及其相变规律[J].光谱学与光谱分析,29(8):2112-2116.
李海燕,张世红.2005.黄铁矿加热过程中的矿相变化研究-基于磁化率随温度变化特征分析[J].地球物理学报,48(6):1384-1391.
潘小青,沈忠悦,石林权,等.2014.磁化率各向异性在火成岩中的应用[J].地球物理学进展,29(3):59-68.
潘小青,沈忠悦,董传万,等.2012.海南万宁辉长岩体及辉绿岩脉侵位机制的磁组构证据[J].科学通报,57(22):2086-2093.
潘小青,沈忠悦,陈宁华,等.2011.嵊泗岛辉绿岩墙群的侵位方式:来自磁组构的证据[J].地球物理学报,54(12):3269-3279.
石林权,潘小青,沈忠悦,等.2012.嵊泗辉绿岩墙群侵位分析和倒转组构成因探讨[J].地球科学期刊,2(1):1-7.
田莉丽,邓成龙.2001.岩石的磁学性质[J].地球物理学进展,16(2)109-117.
王金海,孟军海,霍成胜,等.2012.环境磁学参数简介[J].工程地球物理学报,9(4):423-427.
杨丹,徐文艺.2014.激光拉曼光谱测定流体包裹体成分研究进展[J].光谱学与光谱分析,34(4):874-878.
Alva-Valdivia L M,De La Luz Rivas-Sanchez M,Arenas-Alatorre J,et al2013.Microscopy and rock magnetism of fine grain-size titanomagnetitfrom the Jacupiranga Alkaline Complex,Brazil:unearthinTi-magnesioferrite nanoparticles[J].Geofisica Internacional,52(2)93-110.
Badia-Romano L,Rubin J,Magen C,et al.2014.Thermomagnetic behaviouand compositional irreversibility on(Fe/Si)(3)multilayer films[J]Journal of Magnetism and Magnetic Materials,364:24-33.
Borradaile G J.1988.Magnetic susceptibility,petrofabrics and strain[J]Tectonophysics,156(2):1-20.
Curtis M L,Riley T R,Owens W H,et al.2008.The form,distribution andanisotropy of magnetic susceptibility of Jurassic dykes in HUSverdrupfjella,Dronning Maud Land,Antarctica.Implications for dykswarm emplacement[J].Journal of Structural Geology,30(11)1429-1447.
Dunlop D J.1990.Developments in rock magnetism[J].Reports on Progresin Physics,53(6):707-792.
Evans M E and Heller F.2003.Environmental Magnetism,Principles andApplications of Environmagnetics[M].California:Academic Press,SaDiego:19-25.
Foster N F,Wozniakiewicz P J,Price M C,et al.2013.Identification bRaman spectroscopy of Mg-Fe content of olivine samples after impacat 6 km/s onto aluminium foil and aerogel:In the laboratory and iWild-2 cometary samples[J].Geochimica Et Cosmochimica Acta,1211-14.
Goienaga N,Arrieta N,Carrero J A,et al.2011.Micro-Raman spectroscopiidentification of natural mineral phases and their weathering productinside an abandoned zinc/lead mine[J].Spectrochimica Acta ParA-molecular and Biomolecular Spectroscopy,80(1SI):66-74.
Heller F.1988.Rock magnetic studies of upper Jurassic limestones fromsouthern Germany[J].Geophys.,44:525-543.
Hrouda F and Kahan S.1991.The magnetic fabric relationship betweensedimentary and basement nappes in the high tatra mountains,NSlovakia[J].Journal of Structural Geology,13(4):431-442.
Khan M A.1962.Anisotropy of magnetic susceptibility of some igneous anmetamorphic rocks[J].Journal of Geophysical Research,67(7):2873.
Lagroix F,Muxworthy A and Hoffmann V.2006.Developments in techniqueand methods related to rock magnetism[J].Physics of The Earth anPlanetary Interiors,154(3-4SI):209.
Liu Q,Roberts A P,Larrasoana J C,et al.2012.Environmental magnetismprinciples and applications[J].Reviews of Geophysics,50(RG4002).
Nriagu J O and Bowser C J.1969.Magnetic spherules in sediments of lakMendota,Wisconsin[J].Water Research,3(11):833.
O′Reilly W.1984.Rock and Minerals Magnetism[M].Blackie,Glasgow79-87.
Petrovsky E and Kapicka A.2006.On determination of the Curie point fromthermomagnetic curves[J].Journal of Geophysical Research SoliEarth,111(B12S27B12).
Rochette P,Aubourg C and Perrin M.1999.Is this magnetic fabric normalA review and case studies in volcanic formations[J].Tectonophysics307(1-2):219-234.
Rochette P,Jackson M and Aubourg C.1992.Rock magnetism and thinterpretation of anisotropy of magnetic susceptibility[J].Reviews oGeophysics,30(3):209-226.
Silva P F,Marques F O,Machek M,et al.2014.Evidence for non-coaxialitof ferrimagnetic and paramagnetic fabrics,developed during magmflow and cooling in a thick mafic dyke[J].Tectonophysics,629(2014)155-164.
Szumiata T,Gzik-Szumiata M and Brzozka K.2007.Modelling othermomagnetic curves obtained with Mossbauer spectrometry fotwo-phase nanocrystalline alloys[J].Materials Science-Poland,25(2)559-564.
Wang S,Lin S and Lu S.2013.Rock magnetism,iron oxide mineralogy andgeochemistry of Quaternary red earth in central China and theipaleopedogenic implication[J].Palaeogeography PalaeoclimatologPalaeoecology,379:95-103.
Zhang Z W and Gan F X.2011.Analysis of the chromite inclusions found innephrite minerals obtained from different deposits using SEM-EDS andLRS[J].Journal of Raman Spectroscopy,42(9):1808-1811.
段宗奇,高星,刘青松.2012.非磁滞剩磁(ARM)及其在地学中的应用[J].地球物理学进展,27(5):1929-1938.
黄菲,寇大明,姚玉增,等.2009.拉曼光谱研究天然Fe S2晶须结构及其相变规律[J].光谱学与光谱分析,29(8):2112-2116.
李海燕,张世红.2005.黄铁矿加热过程中的矿相变化研究-基于磁化率随温度变化特征分析[J].地球物理学报,48(6):1384-1391.
潘小青,沈忠悦,石林权,等.2014.磁化率各向异性在火成岩中的应用[J].地球物理学进展,29(3):59-68.
潘小青,沈忠悦,董传万,等.2012.海南万宁辉长岩体及辉绿岩脉侵位机制的磁组构证据[J].科学通报,57(22):2086-2093.
潘小青,沈忠悦,陈宁华,等.2011.嵊泗岛辉绿岩墙群的侵位方式:来自磁组构的证据[J].地球物理学报,54(12):3269-3279.
石林权,潘小青,沈忠悦,等.2012.嵊泗辉绿岩墙群侵位分析和倒转组构成因探讨[J].地球科学期刊,2(1):1-7.
田莉丽,邓成龙.2001.岩石的磁学性质[J].地球物理学进展,16(2)109-117.
王金海,孟军海,霍成胜,等.2012.环境磁学参数简介[J].工程地球物理学报,9(4):423-427.
杨丹,徐文艺.2014.激光拉曼光谱测定流体包裹体成分研究进展[J].光谱学与光谱分析,34(4):874-878.
Alva-Valdivia L M,De La Luz Rivas-Sanchez M,Arenas-Alatorre J,et al2013.Microscopy and rock magnetism of fine grain-size titanomagnetitfrom the Jacupiranga Alkaline Complex,Brazil:unearthinTi-magnesioferrite nanoparticles[J].Geofisica Internacional,52(2)93-110.
Badia-Romano L,Rubin J,Magen C,et al.2014.Thermomagnetic behaviouand compositional irreversibility on(Fe/Si)(3)multilayer films[J]Journal of Magnetism and Magnetic Materials,364:24-33.
Borradaile G J.1988.Magnetic susceptibility,petrofabrics and strain[J]Tectonophysics,156(2):1-20.
Curtis M L,Riley T R,Owens W H,et al.2008.The form,distribution andanisotropy of magnetic susceptibility of Jurassic dykes in HUSverdrupfjella,Dronning Maud Land,Antarctica.Implications for dykswarm emplacement[J].Journal of Structural Geology,30(11)1429-1447.
Dunlop D J.1990.Developments in rock magnetism[J].Reports on Progresin Physics,53(6):707-792.
Evans M E and Heller F.2003.Environmental Magnetism,Principles andApplications of Environmagnetics[M].California:Academic Press,SaDiego:19-25.
Foster N F,Wozniakiewicz P J,Price M C,et al.2013.Identification bRaman spectroscopy of Mg-Fe content of olivine samples after impacat 6 km/s onto aluminium foil and aerogel:In the laboratory and iWild-2 cometary samples[J].Geochimica Et Cosmochimica Acta,1211-14.
Goienaga N,Arrieta N,Carrero J A,et al.2011.Micro-Raman spectroscopiidentification of natural mineral phases and their weathering productinside an abandoned zinc/lead mine[J].Spectrochimica Acta ParA-molecular and Biomolecular Spectroscopy,80(1SI):66-74.
Heller F.1988.Rock magnetic studies of upper Jurassic limestones fromsouthern Germany[J].Geophys.,44:525-543.
Hrouda F and Kahan S.1991.The magnetic fabric relationship betweensedimentary and basement nappes in the high tatra mountains,NSlovakia[J].Journal of Structural Geology,13(4):431-442.
Khan M A.1962.Anisotropy of magnetic susceptibility of some igneous anmetamorphic rocks[J].Journal of Geophysical Research,67(7):2873.
Lagroix F,Muxworthy A and Hoffmann V.2006.Developments in techniqueand methods related to rock magnetism[J].Physics of The Earth anPlanetary Interiors,154(3-4SI):209.
Liu Q,Roberts A P,Larrasoana J C,et al.2012.Environmental magnetismprinciples and applications[J].Reviews of Geophysics,50(RG4002).
Nriagu J O and Bowser C J.1969.Magnetic spherules in sediments of lakMendota,Wisconsin[J].Water Research,3(11):833.
O′Reilly W.1984.Rock and Minerals Magnetism[M].Blackie,Glasgow79-87.
Petrovsky E and Kapicka A.2006.On determination of the Curie point fromthermomagnetic curves[J].Journal of Geophysical Research SoliEarth,111(B12S27B12).
Rochette P,Aubourg C and Perrin M.1999.Is this magnetic fabric normalA review and case studies in volcanic formations[J].Tectonophysics307(1-2):219-234.
Rochette P,Jackson M and Aubourg C.1992.Rock magnetism and thinterpretation of anisotropy of magnetic susceptibility[J].Reviews oGeophysics,30(3):209-226.
Silva P F,Marques F O,Machek M,et al.2014.Evidence for non-coaxialitof ferrimagnetic and paramagnetic fabrics,developed during magmflow and cooling in a thick mafic dyke[J].Tectonophysics,629(2014)155-164.
Szumiata T,Gzik-Szumiata M and Brzozka K.2007.Modelling othermomagnetic curves obtained with Mossbauer spectrometry fotwo-phase nanocrystalline alloys[J].Materials Science-Poland,25(2)559-564.
Wang S,Lin S and Lu S.2013.Rock magnetism,iron oxide mineralogy andgeochemistry of Quaternary red earth in central China and theipaleopedogenic implication[J].Palaeogeography PalaeoclimatologPalaeoecology,379:95-103.
Zhang Z W and Gan F X.2011.Analysis of the chromite inclusions found innephrite minerals obtained from different deposits using SEM-EDS andLRS[J].Journal of Raman Spectroscopy,42(9):1808-1811.
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