石英岩脆塑性转化的实验研究

 在温度500~1 000 ℃、围压1 251~1 440 MPa条件下进行了石英岩脆塑性转化的实验研究。通过力学行为和变形微观结构研究表明，在实验温度和压力范围内，石英岩经历了半脆性破裂、半脆性流动和塑性变形3种变形阶段。随着温度升高,石英岩在变形机制上发生了两次转化，从半脆性破裂向半脆性流动转化发生在700~800 ℃，从半脆性流动向塑性变形转化发生在900~950 ℃，这两个变形阶段的转化温度比Hirth（1994）给出的各阶段转化温度高100 ℃。在塑性变形域的大应变实验样品中发现了柯石英。

The Brittle-Plastic Transition in Experimentally Deformated Quartzite

Deformation experiments have been conducted to investigate the brittle-plastic transition of quartzite under temperature of 500~1 000 ℃ and confining pressure of 1 251~1 440 MPa. Mechanical behavior and microstructural characteristics indicated that the brittle-plastic transition of quartzite in experimental condition underwent three deformation mechanisms, namely the semibrittle faulting, semibrittle flow and plastic flow. At least two transitions of deformation mechanism were involved with increasing temperature. The first is the transition from semibrittle faulting to semibrittle flow at 700~800 ℃, and the second is the transition from semibrittle flow to plastic flow at 900~950 ℃. In comparison with the similar results reported by Hirth and Tullis (1994), the temperatures of two transitions we determined is higher by 100 ℃ than Hirth and Tullis' results. In addition, coesite was found in the thin section of severely deformed plastic flow samples.