Temperature derivatives of elastic wave velocities in plagioclase (An51±1) above and below the order-disorder transition temperature
Temperature derivatives of elastic wave velocities in plagioclase (An51±1) above and below the order-disorder transition temperature
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DOI：
10.2138/am.2008.2591
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发表时间：
2008-04-01
影响因子：
3.1
通讯作者：
Arima, Makoto
中科院分区：
文献类型：
--
作者：
Kono, Yoshio;Miyake, Akira;Arima, Makoto
斜长石（An（51 +/- 1））的压缩（v（p））和剪切（v（s））波速度测量到900 ℃，1 GPa。nu（p）（偏导数v（p）/偏导数T）和nu（s）（偏导数v（p）/偏导数T）的温度导数在类似于400 ℃时显示出不连续的变化。偏导数nu（p）/偏导数T在400 ℃以下为-0.9 x 10 - 4 km/s/degree C，在400 ℃以上为-4.4 x 10- 4 km/s/degree C。偏导数nu（p）/偏导数T也从-0.7 x 10（-4）增加到-4.1 x 10（-4）km/s/℃。这些nu（p）和nu（s）在25至700摄氏度之间显示可逆变化。相比之下，nu（p）和nu（s）在700-800 ℃时增加（分别为0.08和0.08 km/s），并在加热到800和900 ℃后显示出不可逆的变化。X射线粉末衍射分析表明，加热到900 ℃的粗产物显示出比加热到700 ℃获得的粗产物更高的晶格角γ，其分别与高和低斜长石的晶格角γ相当。我们将高温下斜长石的nu（p）、nu（s）、偏导数nu（p）/偏导数T和偏导数nu（s）/偏导数T的不连续变化归因于斜长石的有序-无序转变。
Compressional (v(p)) and shear (v(s)) wave velocities of plagioclase (An(51 +/- 1)) were measured up to 900 degrees C at 1 GPa. The temperature derivatives of nu(p) (partial derivative v(p)/partial derivative T) and nu(s) (partial derivative v(p)/partial derivative T) show a discontinuous change at similar to 400 degrees C. The partial derivative nu(p)/partial derivative T is -0.9 x 10(-4) km/s/degrees C below 400 degrees C and -4.4 x 10-(4) km/s/degrees C above 400 degrees C. The partial derivative nu(p)/partial derivative T also increases from -0.7 x 10(-4) to -4.1 x 10(-4) km/s/degrees C. These nu(p) and nu(s) show reversible changes between 25 and 700 degrees C. In contrast, both nu(p) and nu(s) increase (0.08 and 0.08 km/s, respectively) at 700-800 degrees C, and show irreversible changes after heating to 800 and 900 degrees C. The X-ray powder diffraction analysis shows that the run product heated to 900 degrees C shows a higher lattice angle gamma than the run products obtained on heating up to 700 'C, which is comparable to the lattice angle y of high and low plagioclase, respectively. We ascribe the discontinuous change in nu(p), nu(s), partial derivative nu(p)/partial derivative T, and partial derivative nu(s)/partial derivative T to the order-disorder transition of plagioclase at high temperatures.