Precise and reliable argon geochronology of high- and ultra high-pressure metamorphic rocks

为揭示高压、超高压变质岩的变质作用及随后的折返过程进行了基础研究。在部分研究成果中，我们建立了配备紫外激光器的微探针Ar-Ar装置。本文通过新仪器和常规仪器的对比分析，探讨了太平洋型造山带高压变质带的地质构造、热构造与多硅白云母年龄的关系。这种方法揭示了两个不同的折返过程的带。我们解释了这种差异是由于俯冲到俯冲带深部的大洋板块边界的性质。

Basic research was carried out to reveal the metamorphism and the subsequent exhumation process of high and ultra-high pressure metamorphic rocks. In a part of the achievement, we set up the micro-probe Ar-Ar facilities equipped with UV laser. With analyses using the new facilities and the conventional ones, we examined the relationships among geological structure, thermal structure and phengite ages of the high-pressure metamorphic belts in Pacific type orogenic belt. This approach revealed two different exhumation processes of the belts. We interpreted the differences are due to the natures of oceanic plate boundaries that subduct into the deeper part of subduction zone.