| 秦岭-大别山壳幔岩石高温高压下的电性特征 |
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| 引用本文： | 高平,杨僻元.秦岭-大别山壳幔岩石高温高压下的电性特征[J].地质科学,1998,33(2):195-203. |
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| 作者姓名： | 高平 杨僻元 |
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| 作者单位： | 1. 国家地震局地质研究所 北京 100029;2. 地质矿产部物化探研究所 河北廊坊 102849 |
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| 摘 要： | 首次报导了秦岭-大别山壳幔岩石高温高压下电导率的测定结果。该区中上地壳主要代表岩石(角闪岩、绢云母石英片岩、千枚岩等)在10-25km的温压条件下,含水矿物出现脱水会引起电导率值升高,认为这是该区出现高导层体的主要原因;中下地壳代表性岩石(片麻岩、麻粒岩、榴辉岩等)由于石英从α相向β相转变,会导致电导率值(σ)下降。在下地壳的温压条件下电导率值一般为10-2到10-3S·m-1;上地幔的代表性岩石由于组成矿物较为基性,电导率值比下地壳高,从0.1到1S·m-1。
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| 关 键 词： | 实验研究 高温高压 电导率 秦岭-大别山 |
| 收稿时间： | 1997-01-10 |
| 修稿时间： | 1997-01-10; |
EXPERIMENTAL STUDY ON THE ELECTRIC CONDUCTIVITY UNDER HIGH PRESURE AND HIGH TEMPERATURE FOR THE CRUST MANTLE ROCKS IN QINLING DABIE MOUNTAIN |
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| Gao Ping\ Yang Piyuan\ Li Yanjun.EXPERIMENTAL STUDY ON THE ELECTRIC CONDUCTIVITY UNDER HIGH PRESURE AND HIGH TEMPERATURE FOR THE CRUST MANTLE ROCKS IN QINLING DABIE MOUNTAIN[J].Chinese Journal of Geology,1998,33(2):195-203. |
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| Authors: | Gao Ping\ Yang Piyuan\ Li Yanjun |
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| Institution: | 1. Institute of Geology, State Seismological Bureau, Beijing 100029 |
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| Abstract: | The dependency of rock electric conductivity on frequency was studied with AC method.Under a given pressure and temperature,the influence of frequency on the electric conductivity is very small within the range of 0.1—10Hz,the electric conductivity increases slightly with increase of frequency at higher frequency range,and this phenomenon is more remarkably under lower temperature than under higher temperature.The result of determination on electric conductivity of crust-mantle rocks in Qinling Dabie mountains was firstly reported.It is shown that:(1)The major representative rocks for middle-upper crust hornblendite,chlorite-schist,sericite-quartz-schist,phyllite,biotite granodiorite and etc.show that minerals of hornblende,chlorite and sericite kind will under go dehydration with some partial melting under the temperature and pressure conditions at the depth of 10-25km leading to the increase of electric conductivity and abrupt change at phase transition point with values of 0.1 S·m-1 to 10S.m-1.That may be the main reason for the formation of high conductivity layers or bodies.(2)The representative rocks of middle lower crustsuch as gneiss,granulite and eclogite etc.,may gorm the lower crust layers of low conductivity.Meanwhile,the layers which are rich in quartz also can lead to the decrease of electric conductivity with the values of 10-1 S·m-1 to 10-3 S·m-1 due to the α to β phase transition of quartz taken place under the pressure and temperature conditions of lower crust.(3)The representative rocks for the upper mantle such as dunite and augite peridotite,are composed of relatively alkalic minerals,being mostly olivine,pyroxene,spinel and garnet,containing ofundant Fe,Mg,Ca,and also possibly fluids.At higher pressure and temperature conditions of upper mantle,the electric conductivity will be higher than that of lower crust,with the values of 0.1 S·m-1 to 1 S·m-1 。 |
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| Keywords: | Exeperimental study High pressure and high temperature Electric conductivity Qinling Dabie Mountain |
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