α-β石英相变的应变参数计算及其地质意义

 利用已有的α和β石英压缩性、热膨胀性、弹性及相变温度压力资料，计算了α-β石英相转变时，α和β石英的晶胞参数。依据虎克定律以及高压下β石英的弹性参数，估算了α-β石英相转变时的应变、应力和应变能。结果表明，在0~1.1 GPa条件下，随压力升高，α-β石英相变的线应变介于-0.006~0.005之间，体应变介于-0.016~0.012之间，应力介于-0.46~0.14 GPa之间；应变能介于965~2 760 kJ/m³之间。压力为0.5 GPa左右时，α-β石英相变的应变、应力和应变能均达到最小值。在此基础上，讨论了壳内大规模酸性岩浆活动引起的α-β石英相变对壳内岩石的作用。

CALCULATION OF THE STRAIN,STRESS AND ELASTIC ENERGY FOR α-β QUARTZ TRANSITION AND ITS GEOLOGICAL SIGNIFICANCE

The variations of the lattice parameters of α- and β-quartz at high pressure and high temperature are calculated with the compressional and thermoelastic properties of α- and β-quartz. Combined the data of α-β quartz transition experiments with the results of calculation, the lattice parameters of α- and β-quartz at their transition pressure and temperature are determined firstly. Then, the strains, stresses and elastic energies for α-β quartz transformation were evaluated according to Hooke's law. The results indicate that at the pressure of 0~1.1 GPa, the linear strains vary in the range of -0.006~0.005, the volume strains in the range of -0.016~0.012, the stresses in the range of -0.46~0.14 GPa, and the elastic energies in the range of 965~2 760 kJ/m³. At about 0.5 GPa, the strains, stresses and elastic energies achieved their minimum values. Based on the calculation, the effect of the α-β quartz transformation on the wall rock in the crust during the acid magma intrusion is discussed.