高温高压下榴辉岩和斜长角闪岩的弹性波速度和衰减的研究

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	高温高压下榴辉岩和斜长角闪岩的弹性波速度和衰减的研究
	岳兰秀
	2001
学位授予单位	中国科学院地球化学研究所
学位授予地点	中国科学院地球化学研究所
学位名称	博士
学位专业	深部地球化学
关键词	高温高压纵波速度衰减各向导性榴辉岩斜长角闪岩
摘要	本论文选取了斜长角闪岩和榴辉岩作为实验样品，在压力为1.0-3.0 GPa和温度为室温-1300 ℃的条件下，进行了弹性纵波速度和弹性波衰减的实验研究。实验是在YJ-3000吨压力机上进行的，利用超声脉冲透射的方法，首次获得了在压力大于1.0GPa和温度高于800 ℃的条件下的岩石的声波衰减及其各向异性的实验数据。取得如下主要结论：1．榴辉岩的Vp值随压力的升高而增大，在P < 2.0GPa时，上升的速率较快，表明微裂隙逐渐闭合；当P > 2.0GPa时，上升的速率变慢，且表现出很好的线性趋势，这时测得的纵波速度表明了榴辉岩本征的纵波速度，这与前人的实验结果相同。斜长角闪岩的Vp值随压力的变化与榴辉岩的变化相似，不同的是斜长角闪岩的微裂隙闭合压力为1.5GPa。榴辉岩的Vp的Av_p(％)随压力的升高基本保持不变，而斜长角闪岩的Av_p(％)随压力的升高逐渐增大。2.榴辉岩和斜长角闪岩在1.0-3.0 GPa压力下的Vp值随温度的升高而降低，但Vp值在不同的温度阶段，不同的方向上降低的速率和形式不同。如在1.0GPa压力下，当温度小于500 ℃时，Vp值下降较快，说明温度对纵波速度的影响较小；当T > 500 ℃时，Vp值下降的缓慢，说明榴辉岩内部可能发生了结构和应力状态的变化。斜长角闪岩在升温的初始阶段，Vp缓慢下降，并表现出很好的线性趋势。当T > 647 ℃时，Vp下降的速率增大，线性趋势也较好，当T > 1051 ℃时，Vp下降的速率又变小，且比初始时下降的速率要小。榴辉岩Vp的Av_p(％)值随温度的升高而下降，在不同的压力上其下降的速率不同。如在1.0GPa条件下，Av_p(％)随温度的升高而快速下降；在3.0GPa条件下，Av_p(％)值随温度下降缓慢。而斜长角闪岩的Vp的Av_p(％)随温度的变化较复杂，如在1.0GPa条件下，当T < 647 ℃时，Av_p(％)值随温度的升高缓慢增加，当T > 647 ℃时，Av_p(％)值快速增大，当温度达到922 ℃时，Av_p(％)上升到最大值，此后又随温度而减小。3．榴辉岩和斜长角闪岩的弹性波的Q值随压力的升高而增大，其增大的速率和幅度与Vp值的增大形式相同。榴辉岩的Q值的A_Q(％)随压力而升高，而斜长角闪岩的Q值的A_Q(％)随压力基本保持不变。4．榴辉岩和斜长角闪岩的弹性波的Q值随温度的升高而降低，在不同的压力下其降低的速率不同。如在1.0GPa压力下，Q值降低的速率较大；3.0GPa压力下，当T < 300 ℃时，榴辉岩的Q值快速下降，随后下降的幅度减慢，当T > 700 ℃时，榴辉岩的Q值很低，且减小的幅度很小。斜长角闪岩的Q值随温度的变化在1.0-3.0GPa条件下，Q值很小的幅度和趋势相似：当T < 647 ℃时，Q值下降的缓慢，当647 ℃ < T < 1051 ℃时，Q值快速下降，随后下降速率又变小。榴辉岩Q值的A_Q(％)随温度的升高而降低，在1.0和2.0GPa压力下降低较快；3.0GPa压力下A_Q(％)降低较缓慢。斜长角闪岩Q值的A_Q(％)随温度的升高开始缓慢降低，当647 ℃ < T < 105l ℃时，A_Q(％)快速增大，当T > 105l ℃时，A_Q(％)又降低。
其他摘要	The study of experiment in elastic wave velocity and attenuuation were operated at high pressure of 1.0-3.0GPa and high temperatute of room temperattire-1300 ℃ with the pulse transmission by means of YJ-3000 in Institution of Geochemistr, Chinese Academic of Science，Guiyang．The date of elastic wave attenuation and anisotropy at high pressure of more than 1.0GPa and high temperature of more than 800 ℃ in rocks was gained．There are some major conclusions: 1．The compressional wave velocitie(Vp)of Eclogite increases with the raising of pressure．It increases quickly at below pressure of closing microfissure．When the pressure is higher than the pressure of closing microfissure，the increasing of velocity becomes slow．The velocity is intrinsic velocity in Eclogite．The result is same as that of others．The change of velocity Amphibolite is same as that of Eclogite．Howeverthe pressure of the microfissure closing is different between Eclogite and Amphibol ite．It is 2.0GPa in Eclogite and 1.5G Pa in Amphibolite．The Vp in Eclogite and Amphibolite is anisotropic．The anisotropy of Vp in Eclogite has little change with pressure．But the anisotropy in Amphibolite increases with pressure．2．The Vp in Eclogite and Amphibolite decrease with temperature at pressure from 1.0 to 3.0GPa．But it has difietent current in different pressure．For example at 1.0GPa the Vp decreases quickly when the temperattire is below 500 ℃，and decreases slowly at higher temperature than 500 ℃．The Vpin Amphiboiite decreases linearly slowly at the first stage of increasing temperature．Whan the temperature is 647 ℃，the velocity of decrease remarkable．When the temperature is higher than 1051 ℃，the velocity of decrease slowly again．The anisotropy of Vp in Eclogite decreases quickly with temperature．However the variation of anisotropy is difierent at difierent pressure．At 1.0GPa，it decreases quickly．At 3.0GPa，it decreases slowly．The anisotropy of Vp in Amphibolite is different．For example at 1.0 GPa，when the temperature is less than 647 ℃，it increases slowly．And when the temperature is more than 647 ℃，it increases quiekly．When the temperature is 922 ℃，it teached the maximum，at highertemperature it decreases again．3．The quality factor(Q)in Eclogite and Amphibolite increases with pressure．The Q of Eclogite increases quickly when the pressure is less than 2．0GPa．When the pressure is more than 2.0GPa，the Q increases slowly．The variation of Q in Amphibolite with pressure is similar with that in Eclogite．However the pressure of the microfissure closing is difietent between Eclogite and Amphibolite．It is 2.0GPa in Eclogite and 1.5GPa in Amphibolite．The anisotropy of Q(A_Q)in Eclogite increases with pressure．But the A_Q in A mphibol ite strains steadiness．4．The Q of Eclogite increases with temperature．The variation of Q depends on pressure．For example at 1.0GPa，the Q of Eclogite deereases quickly．At 3.0GPa, when temperature is less than 300 ℃，the Q decreases quickly, at higher temperature it decreases slowly．When the temperature is more than 700 ℃，it decreases very slowly．The variation of Q in Amphibolite is difierent with that in Eclogite．It decreases slowly when temperature is less than 647 ℃．It decreases quickly between 647 ℃ and l051 ℃．When temperature is higher than 1051 ℃，it decreases slowly again．The A_Q of Eclogite decreases with temperatute．It decreases very fast at 1.0 and 2.0GPa．At 3.0GPa it decreases slowly．The A_Q of Amphibolite decreases slowly at the beginning of raising temperature．When the temperature is 647 ℃，it begins to increase quickly．When the temperature is 1051 ℃，it begins to decrease．
页数	42
语种	中文
文献类型	学位论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/3584
专题	研究生_研究生_学位论文
推荐引用方式 GB/T 7714	岳兰秀. 高温高压下榴辉岩和斜长角闪岩的弹性波速度和衰减的研究[D]. 中国科学院地球化学研究所. 中国科学院地球化学研究所,2001.

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