【摘要】 系统测定了汶川地震断裂带深溪沟剖面断层泥中石英和方解石颗粒的拉曼谱峰。测试结果表明,受到断层滑动、断裂带构造挤压应力作用,所有样品的特征拉曼谱峰向高波数偏移。所测样品中微裂隙发育、与绿泥石等粘土矿物共生的石英颗粒的464cm-1谱峰向高波数偏移量为2.50cm-1,而比较完整的纯净石英颗粒的464cm-1谱峰偏移量为3.78cm-1。这可能是由于石英颗粒早期发育大量微裂隙,并填充了松散的粘土矿物,增加了石英颗粒的表面积,从而加速了石英内应力的释放。断层泥中方解石颗粒的1 085cm-1谱峰向高波数偏移2.70cm-1,为汶川8.0级地震断层面所受构造压应力所致。根据方解石颗粒拉曼谱峰的变化及已有的实验数据,估计汶川地震发生时断层面所受压应力的下限为496MPa。研究表明,对断裂带内矿物颗粒进行拉曼谱峰测试,可以为推测断层活动时断层面所受到的力学机制提供依据。更多还原

【Abstract】 Quartz and calcite grains in fault gouge at the Shenxigou section of Wenchuan earthquake fault zone were investigated by micro-Raman spectroscopic measurement.All the peaks shift towards high-frequency due to the tectonic stress during fault slipping.The 464 cm-1 peak arising from the micro-fractured quartz grains coexisting with clay minerals such as chlorite shifts by 2.50 cm-1,while the 464 cm-1 peak arising from the weakly fractured and pure quartz grains shifts by 3.78 cm-1.This likely resulted from that the microfissure filling in loose clay minerals increases the surface area of the quartz grains,in which the stress existing in the crystal lattice was accelerated to be released.The 1 085 cm-1 peak arising from calcite grains shifts by 2.70 cm-1 towards high-frequency,as a result of the Wenchuan Ms 8.0 earthquake.The compressive stress in the fault plane was estimated to be at least 496 MPa during the fault slipping when the big earthquake happened according to the Raman peak frequency shift of calcite grains and the available experimental data.The results showed that the Raman spectra of minerals within fault zone should provide information of mechanisms on the fault plane when fault slipping takes place.更多还原